Growing the Desert Garden

Welcome to the Desert Garden, with garden coach Tyler Storey, where we talk about everything having to do with gardening and landscaping in the Desert Southwest. From composting to Cercidium and agaves to arugula — we'll cover everything you want to know to grow your own beautiful Desert Garden.

Saturday, December 27, 2008

More Frost Pics: Cauliflower

Frozen Cauliflower ©Tyler StoreySometimes the garden photos are just too interesting to pass by, even if there isn't a lot to be said about them. The top picture is a cauliflower leaf, photographed this morning just before dawn. Yes, those are ice crystals. The picture below is the same leaf, photographed about three Thawed Cauliflower ©Tyler Storeyhours later.
One wouldn't think the leaf tissue would survive, but clearly it did.

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Stop-Action Broad Bean: Episode 6 – Frost

Frozen Fava © Tyler Storey

Last night and this morning brought the first serious frost of the Winter to this part of the Desert Garden. Air temperature dipped down to around 30° here at The Ranch, but it didn't last for too many hours, and there was little damage to the Winter crops; the peppers, chiles, and eggplant, however, are on their way out after many months of good service.

Our little broad bean and his band of brothers looked pretty bad. The top picture to the left was taken just before dawn, and the plant is clearly frozen; the dark, wet-looking green to the top is a typical sign of frost, and the silvery coloration on the lower portion of the plant is ice crystal reflecting in the camera flash.

Fortunately, one of the things that makes the Fava Bean a good choice for the Winter Desert Garden is that it is fairly frost-tolerant; I would call it moderately hardy. In a light frost, as we had last night, it should recover just fine. If we were expecting a harder, longer freeze, I would give it some frost-cloth protection.

Previously Frozen Fava ©Tyler StoreyAs you can see in the lower left picture, the "frozen" Broad Bean had recovered fully by 10 this morning. Almost hard to believe it's the same plant.

Most of the cool-season vegetables that we grow in the Desert Garden have some degree of hardiness, and will take at least a moderate frost, but the stage of plant growth can make a difference. Peas, for instance, are very hardy as seedlings and plants, but the flowers and pods are fairly frost tender. If you go out some frosty morning and find that your pea pods have a wet, dark green look to them, as in the foliage of the broad bean, above, your best bet is to harvest them right then and have them for breakfast. An even better idea is to protect them the night before.

Lettuces and endive can vary greatly in their hardiness, depending on variety. If you forget to put frost protection on your leafy greens and they freeze, here's an interesting trick you can try: cover the frozen plants first thing in the morning, before the sun hits them; anything that shades the leaves from the sun will work. Then, once the air temperature has come up well above freezing, remove the cover. It seems that frozen lettuce leaves that thaw suddenly, as when the sun hits them, will wilt and die. But frozen lettuce leaves that warm up slowly, as the air warms, will often recover and be fine.


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Tuesday, December 23, 2008

Back at the Ranch: Mid-Winter Vegetable Harvest

Winter Pepper Harvest © Tyler Storey

If you continue to water your Summer and Spring crops, and absent early freezes, you'll find that certain of your vegetables will continue producing into the Winter. Here at The Ranch, the eggplant, peppers, and chiles are still producing.

Don't be surprised if the vegetables you harvest at this time of year are smaller than what you saw in the warmer months; the early heat, later cold, and shortening days result in significantly smaller fruits. The photo shows red and golden bell peppers, and Poblano and Serrano chiles that came out of the garden the other afternoon; all are on the small side, but they all had excellent flavor.

If you saw these in the grocery, you'd probably pass them by, but these are home-grown bounty and there's nothing at all wrong with them.

Growing vegetables at home calls for two adjustments to how most of us have come to view food. First, we need to realize that "perfection" isn't a matter of how something looks, but rather a matter of what it is. And, second, we start deciding what's for dinner on the basis of what's ready in the garden instead of what we can drive off and pick up at the grocery. The second of these is without a doubt the bigger adjustment for the modern American eater.

So what do you do with a mid-Winter bunch of dwarf peppers and chiles?

This particular bunch went into a soup pot with some store-bought onion, garlic, chicken and kernel corn, and were seasoned with cilantro, oregano, lime, and epazote from the garden. In theory, the onion, garlic, and corn could also have come from the garden, but I didn't freeze any corn from earlier, and the onion and garlic went in late this year. Had I grown zucchini this year, some of that would have gone in also.

And if I had chickens . . . . I might have to think about that one.

As I've said before, year-round vegetables are one of the great advantages of living in the Desert Garden. And the more you garden, the more eating what you grow becomes an every-day habit, and not just for special occasions.


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Monday, December 22, 2008


In the spirit of experimentation, I've decided to try out a very limited number of small advertisements on The Desert Garden blog. My primary concern was that the blog would suddenly contain ads for stuff and companies that weren't in keeping with the kind of information I try to convey with this blog. Sure enough: within two seconds of adding the advertising code, I had an ad from the one nursery in the Phoenix area that I tell my clients to avoid. I think I've fixed the problem with a filter, but we'll see.

I welcome your feedback about having advertising on the blog, what ads appear, or any other thoughts you might have on the subject.

Thanks much,


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Sunday, December 21, 2008

From the Inbox: Fruit Flies in the Compost Bin

From a Correspondent:

I recently attended a composting class you taught at the library, and started composting about 6 weeks ago. It’s going well, but there are a ton of fruit flies. I stopped putting in banana peels and I started adding more brown yard waste, but they are still a pain. I would appreciate any advice. Thank you so much.
Gilbert, Arizona

Good morning Dianne,
Aren't those little fruit flies annoying? First, do know that fruit flies are completely harmless; that doesn't make it any more pleasurable to have them zip around and fly up your nose, but at least that's the worst of it. The other good news is that fruit flies thrive in exactly the same conditions as a healthy compost pile so, um, congratulations!

Now, on to business.

With any pest, our best course of control starts with understanding their interaction with the environment in which we find them. That give us the information we need to then alter the environment in such a way as to diminish or eliminate the pest. It might sound touchy-feely to say you have to understand things from the fruit fly's point of view, but it's really rather hard-nosed and practical.

You are correct in fingering the banana peels as being complicit in the fruit-fly issue. Fruit flies love banana peels, and are most commonly introduced into our homes and into our compost piles as larvae that arrive on bananas. From there, they hatch and begin hovering around the ripening bananas and other fruit that may be sitting in the fruit bowl on the kitchen counter, or around the fruit peels that we put in the compost pile. Ripening and fermenting fruit is their source of food, and even though they most frequently arrive on bananas, any fruit will give them an ongoing source of nourishment. Even wine (fermented grape juice, of course) is a great fruit fly attractor, and although the flies are harmless and carry no diseases, there is nonetheless something faintly disturbing about finding fruit flies riding the bubbles up and down in your glass of champagne.

Eliminate the attractors and food sources, and we eliminate the fruit flies.

Increasing the "brown yard waste" or carbon-rich materials in your compost pile is a great first step. This should speed up the decomposition of the fruit wastes in your pile, and also dilute the percentage of fruit-fly attractors in the pile. You have two choices for the next step; you might need to try one and then the other to see what works for you.

First, try withholding all fruit waste, not just banana peels, from your compost pile, and turning the pile daily, or every other day, for the next little while. That should eliminate existing food sources and dry up the fruit-fly population. Plus, it's good practice: any time we have a pest in the compost pile, our first step is to turn the pile more frequently.

The other approach is to continue to add fruit waste, including banana peels, but bury it deeply in the pile out of reach of the fruit flies. Turn your pile before you add new fruit waste, then open a hole at least a foot deep in the center. Place the fruit wastes in the bottom of the hole, and cover it deeply with other material from the bin; this will both exclude it from fruit-fly access and speed up its decomposition, as it will be in the warm and active center of the pile. I tend to favor this approach, as it allows you to keep using your kitchen wastes.

Just so you know, you can also try to trap the little critters. Poke some small holes in a plastic container, place a banana peel in the container, then set the container near the fruit fly swarm. In a day or so, most of the fruit flies will be in the container, and you can dispose of them. This seems like a lot of trouble to me, but if neither of the first options work, give it a try.

For the record, the one thing we can never do for pest control in a compost pile is use any kind of insecticide. There are a number of good reasons why we don't, but, above all, using pesticides indicates a certain lack of creativity.

Do let me know which method you try and how it works for you.

I hope this helps,

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Wednesday, December 17, 2008

Stop-Action Broad Bean: Episode 5

Broad Bean © Tyler Storey

Our little Broad Bean is still alive and kicking, and here it is, to the left. Not really much of a change between last week and today, but I have high hopes. This particular plant appears to be the runt of the bean litter and is lagging behind its fellow bean plants. I had considered switching to another, more vigorous and photogenic bean, but that would violate the spirit of the endeavour, so we'll stick with what we have.

You may notice our bean looks a bit wet from the first of the Winter rains, and that may pop its growth a bit. Winter rains are one of the great advantages to gardening in the Sonoran Desert. Of the four main deserts in North America – the Great Basin, Mojave, Sonoran, and Chihuahuan – only the Sonoran has reliable and significant two-season rains.

The northernmost desert, the Great Basin, covers most of the state of Nevada and small portions of Utah, Idaho, Oregon, and California. Much of its precipitation falls as snow, mostly in late Winter and early Spring.

The Mojave desert, directly to the South of the Great Basin, is the driest of our American deserts and also home to Death Valley, location of the highest temperature ever recorded in North America. It gets some of the Great Basin Winter rains, and some of the Summer rains from the Sonoran Desert, but more or less the leavings of each.

The Chihuahuan Desert, to the South and East of the Sonoran Desert, covers small portions of Arizona, New Mexico, and Texas, but lies predominantly in Mexico. It tends towards higher elevations, and get most of its rainfall in the Summer months.

The Sonoran Desert covers a good portion of Southern Arizona, over into Southern California, then South along either side of the Gulf of California, and is a more subtropical desert, with significant rainfall both from the Summer Monsoon season and the Winter rains; we get the best of both worlds and can easily grow plants native to almost any of the world's desert regions.

As you plan, plant, and care for your own slice of the Desert Garden, it's worth paying attention both to the rain characteristics of where you garden, and to the rain characteristics of where your individual plants come from. Knowing what the weather is like where your plant comes from is one of the best clues to caring for it in its new location.


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Monday, December 15, 2008

Plant to Ponder: Italian Stone Pine

Comus and the Christmas Tree © Tyler Storey

Many of the plants we look for in our local nurseries are only seasonally available, but one of the best trees for the Desert Garden is available only one time of year, and that's right now, just before Christmas. More than that, it's almost only ever available in one size: very small.

The Italian Stone Pine (Pinus pinea) is widely sold in nurseries and all kinds of other stores as a table-top live Christmas tree. What many of us don't realize is that once its Yuletide duties are complete, it can be successfully planted out in the landscape and will become a stunning, large, and eventually edible addition to the Desert Garden.

Pinus pinea is the typical pine tree seen in Italian and Portuguese travel brochures and postcards, and is perhaps the finest of the pine trees for the Desert Garden, though not as frequently planted as the Aleppo and Eldarica Pines. In shape, the Italian Stone Pine is rounded to slightly excurrent in youth, maturing to a broadly flat-topped or umbrella shape, and growing at a moderate to fast rate to 40 to 60 feet tall and 30 to 50 feet wide. It's hardy to about 10°F, takes low to moderate water once established, and will thrive in full to reflected sun.

If you're going to plant out your table-top tree, be certain to keep the soil damp, but not soaking while it's indoors (use a saucer to water the tree, but then empty the saucer after 10 minutes or so), and keep it away from direct heat sources. Plant it out in the landscape when Christmas is over, in a hole no deeper than the rootball in the container, and two to three times as wide.

Remember that this will eventually become a large tree, so plant it away from the house or overhead power lines, and not too close to pavement. Water it in well, and don't let the soil dry completely for several weeks. As the tree grows, be certain that you are watering in a circle as wide as the expanding tree canopy, and to a depth of three feet each time. This will encourage strong and wide rooting.

Gradual removal of lower branches will encourage high growth but clear no more than 6 to 8" of trunk per year or the tree will be spindly and awkward looking forever - when in doubt, leave it alone. The tree pictured above was planted out here at The Ranch shortly after the photograph was taken, about 6 years ago; it is now several feet above the roof line, and about 12 to 15 feet wide.

Eventually, your Pinus pinea will produce pine cones, and these are the source of the pignoli nuts you use in cooking; each cone takes about three years to reach maturity. Plant some basil and some garlic, and you give a whole new meaning to home-made pesto.


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Saturday, December 13, 2008

Subscription Thingy

As a number of you have requested, I have finally added a subscription thingy to the Desert Garden blog. At least I think it's a thingy. It might be a doohickey, but I'm not sure how to tell the difference. In any event, you'll find it part way down the column on the right. While I'm always happy to hold forth on landscaping and plants, I have no idea how the subscription thingy (or doohickey) is supposed to work, so I'm afraid you're on your own. As always, I welcome your questions, thoughts, feedback, and suggestions, so don't hesitate to let me know how it works.


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From the Inbox: Properly Pruning Pepper Trees

From a Correspondent:

As a newcomer to a townhouse complex in Palm Springs, I am struck by the gardening crew's penchant for squaring and rounding bushes and, where our pepper trees are concerned, nearly whacking them to death – all with the blessing of the boss, who claims to be an arborist. Dunno about that. Have yet to see his diploma. Particularly with regard to the pepper trees, I've been assured that they will come back "when the temp hits 90 again" but I'd like your considered opinion on how they should be trimmed. My sense is, as with guns, guys with whackers and saws never see a limb they would not pull the trigger on.
G. Holt

Dear G.,
Where to begin? Hmmmmm.

  1. Fortunately for the world, gun owners are on the whole far more responsible with their tools than are tree trimmers. I favor finger-printing, licensing and extended waiting periods for pruning implements, but I'm not holding my breath.
  2. Welcome to the world of landscaping-by-homeowners-association. Having had the opportunity to consult with many wonderful HOAs, allow me to offer you the voice of experience: as you prepare to take on the landscaping be aware that one of two things will happen: you will find yourself making a positive and enduring contribution to your new community of neighbors, or you will drive yourself and your new neighbors completely bananas and form deep and bitter grudges that will last as long as you own your townhouse. The choice is yours. Good luck.
  3. "They will come back when the temp hits 90 again" is like saying "if I shave my eyebrows off, they'll grow back again." True in both cases, but just because something will recover from the damage we inflict on it, it in no way justifies inflicting the damage in the first place. Time may heal all wounds, but that doesn't lessen the stupidity of the initial action.

Pepper Trees (Schinus molle) should be trimmed exactly like any other tree: remove dead, broken, diseased, and crossing limbs; remove any limbs that touch buildings, or impede vehicular or pedestrian traffic; call the power company if the tree is interfering with power lines.

Now stop, put down your tools, step away from the tree.

In very rare instances, we may thin the interior of a tree's canopy to reduce the chance of wind-throw, bearing in mind that wind-throw is far more a function of improper watering than it is of thick canopies. In no instance do we top, stub, or lion-tail a tree, nor do we ever remove more than 25-percent of a tree's canopy in a given year.

We always select trees because we are looking for the specific qualities they add to the landscape. That is particularly true in the case of Schinus molle. The Pepper Tree adds a very graceful and distinctive weeping green form to the Desert Garden; if we prune it into an odd shape, we lose any reason for having it in the landscape. If the Pepper Trees in your landscape are the wrong shape, or the wrong size, or planted in the wrong place, then they should be removed and some suitable trees planted in their stead. If they are the right tree for the space, then they should be left alone.

One other thing to keep in mind about incorrect pruning: if the Pepper Tree has a draw-back, it is a tendency towards producing brittle and weak growth. Improperly pruning your trees will encourage more vigorous growth, resulting in more fragile and poorly attached limbs. In the future, these may break and fall, potentially resulting in property or personal damage, and a potential liability for your association. For good or ill, California is on the leading edge in the development of case law around liability for incorrectly managed trees.

And last, but by no means least: whether an individual homeowner or an HOA, it is our responsibility to set clear standards and expectations for landscape maintenance people, in detail and in writing. When we don't do that, then we can't much complain about what we get.

I hope this helps,


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Friday, December 12, 2008

When Bad Things Happen to Good Trees: Christmas Lights

Christmas Light Damaged Tree © Tyler Storey

In this Advent season, with Christmas nearly upon us, we might be forgiven for thinking the object pictured to the left is a large candy cane.

It isn't.

But 'tis the season for taking a look at what it is.

The object pictured is the trunk of a Palo Verde tree after its Christmas lights were removed. What's worse is that this photo is of only one trunk of a multi-trunked tree: altogether, three multi-trunked trees in this landscape suffered the same damage. The lights were expertly installed, wrapped snugly against the trunk, and when they were lighted they looked spectacular.

The lights were on the tree for only two months, but the ugly brown stripes spiralling up the trunk will be there for the life of the tree.

It is strangely easy for us to forget the two most basic qualities of trees: they are alive, and they grow. Most of the errors we make in the placement, planting, staking, pruning and care of trees are a result of forgetting those two facts. We have a certain tendency to treat trees not as trees but as wood: infinitely malleable and able to be shaped, altered, decorated and re-formed at will. Despite our best efforts, the trees do not agree (Suggesting that trees have the capacity to "agree" or "disagree" is an example of anthropomorphism, or treating trees not as trees but as humans, which is also incorrect but completely off-subject, and doesn't actually damage the trees.).

I've included the picture of the Palo Verde because the damage is visually obvious, but the mesquite in this landscape may have suffered the most. Evey time the lights were turned on, the mesquite tree oozed thick, curved, gobs of sap from directly below each light; it was very odd. Since the lights were removed, the tree has large brown patches spreading over the trunk. I'm keeping an eye on it for the client, but it's not looking good.

The best and only permanent way to light your trees is with landscape lighting, which is always a beautiful addition to the desert landscape. Send me an e-mail and I'll set you up with an expert, and very reasonable, landscape lighting installer. If you must use Christmas lights in your landscape trees, limit yourself to one of two methods: drape strings of lights very loosely around the branches, or buy the light "nets" that can be draped over the entire tree canopy. Both methods have drawbacks, but neither will cause anywhere near the damage of wrapped lights.

Remember: Christmas lights really belong only on Christmas trees, and should be lighted while standing around singing "Angels We Have Heard on High." I never remember the words to the second and third verses, so I just hum along and then make up for it by really belting out the chorus.


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Tuesday, December 9, 2008

Stop-Action Broad Bean: Episode 4

Broad Bean Seedling © Tyler Storey

When last we visited our Broad Bean, it was barely poking its head out of the mulch and looked pretty much like a wad of chewing gum. As you can see, it's come a long way in the past week.

If you look closely at the photo, you'll notice a blurry cross-hatching in the foreground. That's the bird netting with which the planting bed is covered.

Whenever we plant seeds directly in the planting bed, it's worth assuming that the birds will be after them as soon as they sprout. A number of different birds will go after and eat the seedlings; from a bird perspective, this makes sense: as human aficionados of sprouts will tell you, seed sprouts are packed full of nutrition; the birds will gobble them right down.

There are some seedlings that don't seem to appeal to avian tastes, but that doesn't stop the birds from trying them out. Kind of like a person who goes through a box of chocolates, tasting and rejecting each one, the birds will go right down the row, pulling out each seedling and casting the unpalatable ones to the side. Some birds, such as the Curved-Bill Thrasher seem less interested in the seedlings themselves,and more interested in digging around each of them in search of insects; the result, however, is the same.

In this particular bed, the Broad Bean plants are probably now large enough that the netting could be removed without fear of avian predation, but since this same bed also has sprouting carrots, beets and cilantro, I'll leave the netting on for awhile yet.

Interestingly, the bird behavior isn't the same every year. Depending on the weather, availability of other food sources, migration patterns, and other factors, there may be years when you can leave a seed bed uncovered and have not the slightest damage. But since that's unpredictable, make it a habit to net your seed beds as a matter of course.


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Wednesday, December 3, 2008

Plant to Ponder: Saffron Crocus

Saffron Crocus © Tyler Storey Some plants we put in the landscape just because they're beautiful, others because they're edible, or functional, or have an interesting story. Some, like Crocus sativus, the Saffron Crocus, are all of the above.

Crocus sativus, as you can tell by the botanical name, is part of the familiar Crocus family. The species epithet, sativus, comes from the Latin word meaning "cultivated," a good descriptor, as we have evidence of saffron being cultivated as far back as the Minoans and beyond. Saffron has been a painting pigment, a fabric dye, a sacrifice to pagan gods, and, most famously, a spice for food.

Saffron is the key ingredient in paella, and here at The Ranch it regularly appears in Morrocan lamb and lentil harira and in a Risotto Milanese with morels (you wouldn't think that a combination of saprophytic fungi, animal bones, fermented sheep's milk, and crocus parts would taste so good, but such is the miracle of cooking).

The edible portion of the plant, the part called Saffron in the spice trade, is the stigma, three per flower. In the picture above, the stigmas are the brilliant orange thread-like structures. Harvest these with tweezers a couple of days after the bloom is fully open, and dry carefully before storing them away in a spice jar. Yes, they're tiny, but if you purchase them at the market they go for around $1000 a pound, so don't sneeze.

Overall, the Saffron Crocus is tiny, reaching only a few inches in height and is easily overlooked in the garden. It is widely grown in Mediterranean climates, and thus does well in those areas of the Desert Garden where we re-create more Mediterranean conditions, as in your existing herb garden. Hot and dry, with occasional irrigation, well-drained soil and full to perhaps very slightly filtered sunlight suit it well. Dig up and divide the bulbs every couple of years to keep the plants vigorous; wait until the foliage dies down in late Winter or very early Spring.

The Autumn Crocus, Colchicum autumnale is superficially similar in form and habit to the Saffron Crocus, differing most notably in being deadly poison – always an important consideration when cooking. The Autumn Crocus also lacks the deep orange stigmas, so as long as that's the only part you're harvesting from crocus in your garden, then no problem.


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Thursday, November 27, 2008

Stop-Action Broad Bean: Episode 3

Broad Bean Sprout© Tyler Storey

In this Winter's Stop-Action series, we'll follow the life and times of a Broad Bean, commonly known as the Fava Bean. You'll notice we're jumping right in with Episode 3; the first two weekly episodes consisted of fairly uninteresting photos of a blank bit of soil and mulch. All sorts of interesting stuff was going on out of view underground, but to the casual observer it still looked pretty much like a blank bit of soil and mulch, so we're jumping forward to the action shots.

In the Desert Garden, our Fall and Winter vegetable gardens consist for the most part of the "true" vegetables, those plants such as lettuces, carrots, spinach, etc., of which we eat a part of the plant itself (leaves, roots, stems). The two notable exceptions are English Peas and Broad or Fava Beans; in the case of these two "vegetables" we eat not the plant, but the fruit (peas and beans, respectively).

In Italy, the traditional date for planting Fava Beans is All Souls Day, November 2, and that date works well in the Desert Garden, though I wouldn't hesitate to try them earlier or later. The seeds take between 10 and 25 days to emerge from the soil, so the little sprout pictured above is right on schedule. At the moment it looks like nothing so much as a well-chewed wad of neon-green gum, but in the next few days, all those ridges and bumps will resolve into tidy stems and leaves. Just wait: that wad of gum is going to turn into a very pretty plant.


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Monday, November 24, 2008

Back at the Ranch: Wildflowers v. Weeds

If you've sown your desert wildflower seeds over the past month or so, and given them a bit of water, they should be germinating and sprouting about now. Take a look around the garden and you'll find all sorts of little green bits poking their heads up.

But, as the poet says, not all that glisters is gold. In the Desert Garden right now, not all that is green is good. Many of those sprouting plants are, in fact, weeds.

The conditions that favor wildflowers also favor annual weeds, and it can be difficult to distinguish between the two when they're in the seedling stage. Our goal with weeds is always to pull them while they're small, and the amount of time and effort needed to cull weeds when they're new is but a fraction of the work it takes to get them when they are established.

The only way to get rid of the weeds while keeping the wildflowers is to learn what each looks like when it's in the seedling stage. That's not as hard as it sounds; as with much of gardening, it's really just a matter of attention to detail followed by a little practice.

To get you started, I've appended some photos of several common desert wildflowers and several common weeds, each in the seedling stage. Click on any picture to view a larger version. Some of the photos are a bit blurry, but it was early in the morning and I'd consumed prodigious amounts of coffee.

Wildflower: California or Mexican Poppy. These might at first be mistaken for blades of grass, but their slight bluish gray color and distinct "2-pair" structure set them apart.

Wildflower: Toadflax. This is a whole clump of Toadflax seedlings. They tend to put up a relatively long and thin stem before forming their first true leaves.

Weed: Spurge. Not a seedling in this photo, but there's plenty of it around this time of year, so pull it when you see it.

Wildflower: Scarlet Flax.

Edible Radishes. I spilled some seeds here and they grew.

Weed: Prickly Lettuce. Don't let the name fool you: it's not edible, but it is a particularly difficult weed to get rid of once it grows.

Wildflower: Penstemon. For scale, note that the round black object below and to the left of the seedling is a Washingtonia palm seed of somewhat less than a quarter-inch diameter.

Wildflower: Desert Marigold. It's a fuzzy photo, but then it's a fuzzy plant. The first (seed) leaves are easily mistaken for a weed but the first true leaves are silvery and pubescent. Again, note the palm seed for scale.

Wildflower: Desert Marigold. These are a little further along than the one above, and quite distinctive once you learn to recognize them.

Wildflower: Desert Bluebell. Another distinctive wildflower seedling, the Desert Bluebell tends to have very small dark, almost purplish, spots on even the seed leaves. Once you spot a few of these, you won't confuse them with any other plant.

Wildflower: Desert Bluebell. Showing the first pair of true leaves.

Weed: Bur Clover. This is an unpleasant weed, forming little spiral burs, actually seed cases, covered with very sharp spines. These burs are painful to step on and the number-one most likely things to get stuck in your dog's pads. Note that the seed leaves are elongated ovals, the first true leaf is a one-leaf clover, and the second leaf is a three-leaf clover. These seed leaves are easily confused with a wildflower, so it's best to wait until you see at least one true leaf before pulling.

Wildflower and Weed: Scarlet Flax on the right, and Bur Clover on the left. Note that the seed leaves (lowest pair) on each of these plants are very similar. As noted above, wait for some true leaves before deciding to pull or keep.

Weed: Cheeseweed. Perhaps the most distinctive seed leaves of all, these are heartshaped on thin petioles. Pull these when you see them; they are a bear when they get bigger and they re-seed fast.


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Friday, November 7, 2008

From the Inbox: Managing a Compost Bin

From a Correspondent:

I have become an avid composter with a compost bin I purchased from Costco around 9 months ago. Over the summer it seemed to dry out and I added water to it every couple of days. I usually “aerate” my compost daily or every other day with a tool I have that is a metal bar with 2 wings on the end.

I have been pulling compost out of the bottom openings for my garden and winter lawn. Everything is broken down with the exception of dried grass. Some of the compost seems almost like mud – thick and dark brown – is that OK? Do you think it is because I put in water this summer? Also is it OK to use the compost if some of the grass isn't completely broken down or do I need to be more patient?
Cori Pearson

Good morning Cori,
From your description, it sounds like there are a couple of issues at play with your compost, but they are all easily fixed.

First, let's consider your composting bin. From what I know of the composters sold at Costco some while back, I am guessing that your bin is more or less a cube, slightly narrowed at the top like a truncated pyramid, about three feet tall, bottomless, and has "doors" on the lower edges of all four sides.

Composting bins of this type are often marketed with the idea that you put the stuff in the top, it works its way down as you aerate and water it, and then you take "black gold" out of any of the conveniently placed doors at the bottom. It's a nice idea, but actually results in what you're seeing: some good compost, some anaerobic goo, and some dried stuff. The good news is that your compost bin will work great, as long as you use it differently.

Before I tell you how to fix it, let's revisit the basic process of composting: in the presence of air and water, carbon- and nitrogen-bearing organic materials are broken down by aerobic (air-loving) organisms into humus. Humus is the stuff we call compost. The key in looking at that recipe is to realize that each of those four ingredients – nitrogen, carbon, air and water – must be present at every place in the pile. A corner with lots of water and no air will rot anaerobically; another corner with plenty of air and carbon but no water or nitrogen will just sit there. That's the reason that turning or mixing the pile, rather than just aerating it, is so important.

The thick and muddy brown stuff you're seeing is the result of anaerobic decomposition, a consequence of too much water and too little air. The dried grass is a result of too little water and not enough turning and mixing.

You might be thinking that your three-foot-tall compost bin with a narrow top opening is going to be very hard to reach into to turn the pile, and if that's what you're thinking, you are right.

So here's what we do instead:

Using your current compost bin, build a pile as you would normally, layering carbon-rich and nitrogen-rich materials in alternating layers and sprinkling a bit of water on each layer as you go along. Put on the lid.

Go to a hardware store and buy a spading fork; it's like a pitchfork with flat tines.

After a day or two, open the lid of the composter and one or two of the side doors; you should find the pile warm, and maybe even a bit steamy. Using your brand spanking new spading fork, start pulling material out of the side doors – from the bottom – and dumping it into the top opening (lift with your legs, not with your back). Fork out and dump no more than about a quarter of the pile, reaching into the bottom corners to be certain you get the stuff hiding in the angles.

As you turn the pile, pay attention to the moisture levels: you want the pile to be as moist as a wrung out sponge. If it's dry, water it some from the top.

Close up the doors and the lid, and repeat daily or in a couple of days; the more frequently you turn the pile, the faster the compost works. What you will be doing is turning the entire pile several times over as the compost works, mixing it thoroughly and taking the opportunity of regular turning to be certain that the pile is neither too dry nor too wet. What you will also be doing is getting a nice light leg workout on a regular basis; shapely calves are only one of the side benefits to properly managed compost.

As for the material you have right now – the dried grass and the brown gooey bits – go ahead and run them through your new composting method and they will have more value in the garden.

And last, but not least: take your aerator with the wings on the end, turn it upside down and push the metal bar firmly into a convenient patch of soil. Then use your oxyacetylene welding outfit to fashion and attach a beak, possibly an eye (or two), and, if you wish, some random feathers. That makes it art, and don't let anyone tell you otherwise.

I hope this helps,


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Monday, November 3, 2008

From the Inbox: Composting Bins

From a Correspondent:

Is there a particular type of composter that works better in our environment? I have an irrigated yard.
Thank you.
MJ, Phoenix, Arizona

Good morning MJ,
As you may have noticed there are a lot of different composting bins for sale, and any number of plans available for building one yourself. Rather than making recommendations from among them, it's probably more practical if I give you some standards and characteristics that you can use when deciding.

  • Your ideal compost pile is about 3' x 3' x 3', a cubic yard. Any smaller and you may not achieve the mass needed for the process; any larger and you run the risk of anaerobic activity in the middle, and you may not be able to turn it. Five feet to a side is about the largest you'll want to go.
  • Be certain your bin has holes or vents for air circulation through the pile. Simple holes rather than adjustable vents are all that's needed.
  • The bin should have a lid to hold in moisture, though you can use a tarp if a lid is lacking, and the bottom should be open to allow drainage and prevent anaerobic decay.
  • The sun is intense in the Desert Garden, so look for a sun-resistant material; if you build it yourself, wood and wire works great.
  • Your compost bin should have easy access for turning the pile frequently; if it's hard to get to or too tall to reach down into, you're less likely to turn it as much as is needed. Many cities drill holes in used municipal waste containers and offer them as free or inexpensive composting bins. They have lids and are great but can be hard to reach into with your turning fork. With these, try removing the lid, turning them narrow end up, and setting the lid back on the new top; then, when it's time to turn the pile simply lift the can up and off the pile, set it to one side, and then turn the pile contents back into the bin.
  • I recommend you avoid rotating composters, but if you just can't resist, get one that spins on the long axis rather than end over end, and has inside baffles to turn the compost. The pickle-barrel composters that flip end over end are almost impossible to turn once the material is inside, and tend to produce large clumps of gooey smelly stuff.
  • Don’t get a composting bin that is intended to make "compost tea." This is the desert and our soils need organic humus material, not weak brown fertilizer. Also, with our warm climate the potential for pathogen growth in the tea far outweighs any supposed benefits.
  • Avoid bells and whistles – compost is a very simple process that in nature occurs under a tree in the forest; there's no benefit to paying for the fancy stuff.

In short: a simple bin of about a cubic yard that admits air, holds moisture, and is easy to get into.

Because you have an irrigated yard, you’ll want to place the composter in an area where it won't be in standing water, for even the shortest time. If your compost sits in the flood plain, you will generally end up with an anaerobic mess at the bottom of the pile.

I hope this helps,


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Wednesday, October 22, 2008

From the Inbox: Of Rabbits and Worms

Hornworm on newly purchased tomato plant, with tell-tale poop © Tyler Storey From a Correspondent:

So, my friend is now zero for four on tomato plants. Two got eaten down to the nubs in the garden. She bought two more. One got eaten by a hornworm while sitting on her counter overnight and one that she planted has just two leaves. Do rabbits or birds eat the actual plants? I never had problems growing tomatoes - just the fruit was eaten. She doesn't see how rabbits could get in.
Monica, Phoenix, Ariz.

Dear Monica,
I am struck by the image of a caterpillar sitting on your friend's counter, spending the night-time hours casually munching away at tomato plants. It brings to mind John Tenniel's illustration in "Alice's Adventures in Wonderland." But, it sounds like your friend has a serious problem, so let us set aside juvenile interests such as children's illustrated literature and move on to serious garden writing.

Which brings us to Beatrix Potter's "The Tale of Peter Rabbit." "The Tale of Peter Rabbit" is often mistaken for children's literature, but it is nothing of the sort. It's a precautionary tale, a warning, a dark fable, a gardener's dystopia, if you will.

While a casual reading of the tale tends to invoke our sympathies on behalf of the poor trapped rabbit, unjustly persecuted by the horrible Mr. McGregor, from the gardener's perspective it's clear: Mr. McGregor is the wronged party. Peter, as cute and cuddly as he may have been in his blue coat with large brass buttons, was clearly the aggressor. Mr. McGregor was simply defending the fruits (and vegetables) of his labor, and it is with him that our sympathies may properly rest.

The lesson we must take from "The Tale of Peter Rabbit" is that nothing will stop a rabbit once it has determined to ravage a garden. Rabbits will eat nearly any kind of vegetable garden greenery and, in the world of rabbit depredations, two tomatoes are but small potatoes (so to speak). In an area with rabbits, the only solution is to adequately fence the garden, including running the fencing down into the ground, or out along the ground for a foot or so on one side or the other to avoid tunneling.

As to the hornworm, it is sound practice to always inspect newly purchased tomato plants for hitchhiking hornworms; they are commonly found on purchased plants and can make short work of them.

There is a silver lining to the destruction wrought on your friend's tomato plants: now, at the end of October, is far too late to be setting out tomato plants, and, had they lived, they would have been setting fruit just about the time they got whacked by the first hard frosts. The rabbits and worms have saved your friend that particular trauma. Tomato plants in the Desert Garden are best set out in late February and March and again in late July and August, to give them adequate time to form and ripen their fruit.

I hope this helps,


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Sunday, October 12, 2008

From the Inbox: Autumn Vegetable Gardening

From a Correspondent:

My friend wants to plant a small vegetable garden in Surprise, Arizona. She has kids she hopes will enjoy the experience. What can she plant right now that will produce produce (now that's funny!) before it gets too cold? She has no gardening experience so nothing too picky or exotic.

Generally when I get a note claiming a question is being offered on behalf of a "friend," I'm a little suspicious. But since living in Surprise and having children are both perfectly respectable activities, we'll have to take "Monica" at her word.

Good morning Monica,

"Picky" is on the plate of the beholder, especially when it comes to kids, but one of the great advantages of gardening with children is that they will almost always eat what they've grown themselves – even if it's something they wouldn't touch coming out of the grocery. In truth, some of us never grow out of that habit: I feel much the same way about eggplant.

The Desert Garden vegetable calendar has roughly two primary growing seasons: Autumn and Spring; each has a different list of crops. When in doubt, remember this: Autumn through Winter is the season for roots and leaves, and Spring into Summer is our season for fruits.

In practice what that means is this time of year we plant those vegetables whose edible parts are the roots and leaves: carrots, radishes, lettuce, and spinach, for example. The exception to that rule is peas; we eat their fruit but they're an Autumn and Winter crop.

Whatever the season, the key to vegetable gardening is the soil; a little extra effort up front will yield greatly improved results. First, find an area of yard that will get at least 6 to 8 hours of sun a day, clear it of weeds and any grass, then use a spading fork to turn the soil 8 to 12 inches deep; if you find the soil is too hard for turning, water it slowly and deeply, then wait two days and turn it then. Never dig in really wet soil. Next, spread a layer of compost about six inches deep on the top and spade that into your loosened soil, breaking up any large dirt clods as you go (clod-breaking is a good kid activity). Mix it well.

Note: you can use manure instead of compost, but take these precautions if you do. First, use only well-rotted steer manure, never fresh. Next, water it in well after digging it in and then let it "mellow" a few days before planting, to avoid damaging your new seeds or plants. And don't use manure for those areas where you'll be planting root crops, or you can end up with all greenery and no root. I have done this; don't let it happen to you.

You'll find that you now have a bit of a raised bed; this is good. Use a rake and pull some of the soil to each of the sides of the bed to form a raised edge or lip that's higher than the planting area. You'll plant within the watering basin you just created, and the lip will help to hold the water in.

The following vegetables are among the best for planting now in the middle of October:

From seed:

  • Beets
  • Bok Choy
  • Broccoli
  • Brussels Sprouts
  • Cabbage
  • Carrots
  • Cauliflower
  • Celery
  • Chard
  • Collards
  • Endive
  • Kale
  • Lettuces of all kinds
  • Onions (green)
  • Peas
  • Radishes
  • Spinach
  • Turnips

From plants or sets:

  • Broccoli
  • Brussels Sprouts
  • Cabbage
  • Cauliflower
  • Garlic (from cloves)
  • Lettuces
  • Onions (bulb and green, from sets)

I hope this helps,

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Friday, September 19, 2008

From the Inbox: Caterpillar Poop

From a Correspondent:

Can you help me identify this stuff on my plants? I have a raised bed and containers full of edibles. The unidentified problem things look like small peppercorns and collect on the leaves of my basil, mint, and arugula plants. It has not (so far) collected on my green beans, tomatoes, peppers, cilantro or thyme. Although they look like peppercorn, they're not hard. I wipe them off with a paper towel and they mush into a dark green slime, and look kind of like rabbit poop. I always notice them in the morning. They collect on the leaves, and especially in the hard to reach nooks of the folded leaf sprouts near the root of the plant. It's often, but not always clustered. So, there might be like two or five on a bigger leaf. They remove very easily, but there are so many that I can not possibly keep up.
Are these larvae of some kind? We have lots of moths, so maybe they're moth larvae? Or, is it the poop of some large bug or caterpillar? It's just now beginning to collect on my treasured wild arugula, so the damage remains to be seen. However, I'm worried, because several months ago, when I started noticing them on my basil and mint, those plants started to deteriorate. The leaves became holey, they stopped growing, or produced much smaller new leaves than previously. These symptoms may not be related...but I suspect they are.
Any thoughts?
Los Angeles, California

Good morning Julie, and thanks for providing such a detailed description.

Your third guess was a charm: what you're seeing is caterpillar excrement, left behind as the caterpillars eat the leaves of your basil, mint, and arugula, which tend to be great caterpillar favorites. We frequently see caterpillar poop as a hard blackish pellet, but if they're eating lush plants with plenty of moisture, the bug poop will be as you describe.

Caterpillars have extremely simple digestive systems, and what goes in the one end is much the same when it comes out the other end, just ground up a bit; caterpillar-made pesto, as it were. Little-known fact: caterpillar poop from caterpillars eating basil tastes like basil, from those eating mint, like mint, etc. At least that's what I'm told. Check it out for yourself. Go ahead, you first.

There are two effective methods for limiting the damage to your plants. The first is to go out at night, while they're feeding, and use a flashlight to locate them on the leaves and along the stems. Then pick them off and discard them away from the garden; they make great chicken food. This can be somewhat labor intensive, but it also costs nothing.

Because it sounds as if you might have a more extensive problem, your next best method is to spray your plants' leaves with a solution of Bacillus thuringiensis (also called Bt). This is a completely safe and effective biological control that works by giving the caterpillars a terminal stomachache. It works only on caterpillars and has no residual effect on the edibility of the plants. You should be able to find Bt at any nursery or garden center; Dipel and Thuricide are two brands, but there are others as well. As with all pesticides – even organic ones – always read and follow the label exactly.

Because the Bt needs to be ingested to work, don't be surprised if the damage continues for several days.

I hope this helps,


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Monday, August 4, 2008

Back at the Ranch: The Missing Pumpkin

Missing Pumpkin © Tyler Storey

My apologies for the long silence. After a trip out of town, I've been attending to all the issues that affect the Desert Garden when one walks out on it in the middle of Summer.

Foremost among these has been the Mystery of the Missing Pumpkin. If you look carefully at the picture above, the first thing you'll notice is the complete absence of pumpkin vine. I have spent a good long time peering at that particular patch of soil, and the closest examination has thus far failed to reveal even a single pumpkin vine. It appears to be nothing but a patch of garden soil with a smattering of bark mulch. I may be missing something, but it seems unlikely.

When I left town that now-barren patch of soil was full of pumpkin vine; stems running hither and thither, tendrils curling in every direction, and yet-unopened flower buds practically pulsing with pumpkin potential. In a fit of cleverness, I had this year decided to sow my pumpkin seed in the corn-patch, and while the corn was long-finished, its dried stalks continued to provide shelter and support for the burgeoning pumpkin vines.

All gone.

Of the many things we learn from growing a vegetable garden, surprisingly few of them have to do with plants and soils and insects. Building good soil, planting appropriate plants, and squishing bugs as needed are pretty easy to grasp. It's the less concrete skills that are so often the mark of a successful gardener: faith, hope, charity, patience, moderation, contentment, diligence, generosity, resilience; these are among the virtues that really make a garden work.

Despite having been advised that there was no need for any exertion greater than watering and picking vegetables, one of the friends who generously looked after the vegetable garden in my absence proudly informed me on my return that he had taken upon himself the extra-credit task of digging out the dead corn stalks so things would look tidier. When one willfully abandons one's vegetable garden in the middle of Summer and leaves it to the volunteer ministrations of kindly friends, one forfeits the right to ask, "So, did you happen to notice any pumpkin vines in the midst of your massacre?"

I am practicing resignation, gratitude, forgiveness, and humor. Wish me luck.


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Wednesday, July 23, 2008

From the Inbox: Pruning Paint

From a Correspondent:

I hope you can help.  I have a huge fig tree growing in my backyard. Three of the limbs broke from being too heavy with leaves and fruit. I would like to know if I should apply either pruning paint or tree tar on the limbs that have been cut.  If the cut limbs need some kind of product put on them, could you recommend a product?
Thank you for your help.
Carson, California
Hi Aurora,

While I'm sorry to hear about your breaking fig tree, I do have good news: you don't need any kind of pruning paint or wound dressing.  More than that: you don't want any kind of paint or dressing.  

Trees, for the most part, do a wonderful job of taking care of themselves; the breaking of fruit-laden limbs reminds us that there are exceptions.  When it come to recovering from wounds, though, trees are best left to their own devices.  Pruning paint, sealing tar, and other kinds of wound dressings have been found to do no good in protecting the tree, and it appears that they may actually interfere with the tree's own process. 

Any time we prune a tree, whether to shape it or as a result of accidental damage, as with your fig tree, the tree is wounded and its outer protective covering (the bark) is compromised.  As when a person has a cut, this damage opens up the tree to the possibility of disease or insect damage.  Unlike a human or animal though, a tree doesn't really heal a wound; trees seal their wounds instead.  

The late Dr. Alex Shigo did extensive research which showed that trees undergo a process he called CODIT, an acronym for "compartmentalization of damage in trees."  The short version is that trees seal off their damaged areas from their undamaged areas, and eventually may also recover the outer area of the damage bark with a new layer; if you've ever gone back and looked at a tree you pruned a few years earlier, you have probably seen where the cut is now covered over with new bark.  

What does all this have to do with pruning paint?  I'm glad you asked.  Pruning paint or other wound dressings interfere with the natural sealing process of the tree and can actually prevent it from taking place.  Air exposure, sap weeping, decay organisms and all the other things we hope to "correct" with the use of pruning paint are all critical parts of the tree's sealing process.

Do go ahead and remove the ragged stubs where your fig's branches cracked, but other than that, you'll be best served by leaving the tree to recover on its own.  

Next year you may wish to thin the fruit a bit in advance, and consider cutting back on your frequency of watering if you think that might be contributing to over-vigorous growth and weak limbs.

I hope this helps,


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Tuesday, July 15, 2008

Stop-Action Quince: Part 9

Quince, Week 12 © Tyler Storey

Our quince is still alive and kicking, if admittedly somewhat lacking in high-energy dash and adventure. Such is the quiet nature of gardening.

It's the last we'll see of it for a couple of weeks, because as of today I'm taking a short vacation.

One of the great challenges in growing fruits and vegetables in the Desert Garden is that there often comes a time — usually just about now — when the desert gardener finds a need to escape the heat for a short venture to cooler climes. Vacation, in other words. Unfortunately, this tends to coincide with our mid-summer harvest and with our greatest mid-summer heat. And since nothing is more disappointing than returning from vacation to find a dead garden full of rotted produce, we need to take some steps to keep things going while we're gone.

I recommend equal parts mulch and neighborliness.

First, be certain that all your fruit trees and vegetable beds are well-mulched, and give everything a thorough soaking just before you leave.

Next, call or drop in on one or more of your neighbors. Here's the script: "I'm going to be gone for a few days, but I have lots of [tomatoes, peppers, eggplant, chiles, squash, etc.] ripening in the garden. Please come over and pick as much as you'd like."

This being Summer in Arizona, your neighbor is almost guaranteed to respond by asking if you need anything watered, to which you reply: "Thank you, if you see anything wilting that would really be great."

Don't limit yourself to the neighbors you're on friendly terms with.

This is an excellent opportunity to mend fences with those neighbors you've been feuding with all this time. Just grit your teeth, gird up your loins, march right over there and be neighborly.

Giving away food is a great way to make friends. And being neighborly is good for you.

Just remember: if you come home and everything is dried to a crisp, you can't get mad at the neighbor. That really would defeat the whole purpose.


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Monday, July 14, 2008

Back at the Ranch: Pepper Harvest

Chiles Serrano and Bell Peppers © Tyler Storey

Peppers and chiles are gratifyingly tough plants in the Desert Garden. For weeks after the tomato plants are protesting the heat and the intense Summer sun, pepper plants — given adequate irrigation — continue to put out and maintain fresh green growth. The fruits themselves may need a little more care.

One of the questions I hear with great frequency this time of year is: "Why do my peppers (or chiles) have light tan patches on them? What can I spray on them?"

No spraying necessary.

Those light tan patches, usually sunken, and sometimes slightly soft, are sun-scald. They form in areas where the fruit is subject to intense mid-day sun. If you look carefully, you'll find that they appear almost exclusively on the top or West side of an individual fruit, and in a place where there's a break in the foliage cover.

If you catch the fruit early, you can go ahead and eat it; just cut out the tan area. If you wait too long, you'll find that rot will set in and render the fruit inedible, but keep in mind that the rot is secondary to the scald and not the cause.

To prevent sun scald, keep your pepper and chile plants well-irrigated so they continue to form leafy canopy growth to shade the fruit. If you see scald anyway, construct a light frame over the plants and drape it with light shade cloth to block the most intense sun from overhead and the West. Be certain the frame is well-anchored in the soil and the cloth is well-attached; sudden monsoon winds can — and will — send your frame and cloth flying.


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When Bad Things Happen to Good Trees: Part 1

Even in the Desert Garden, there are times when we could say that no water is better than wrong water.

Last week I was called out to look at a leaning Palo Verde tree. This tree is planted near a drive, on the North side of the house, in an area altogether about 12 by 12 feet; not ideal, but not bad. The tree had been growing well, even vigorously, and was nearing 20 feet in height. Then suddenly it took a dive at about a 20° angle towards the East, partly blocking the walk into the house.

As I looked at the tree, three things were immediately apparent: first, the soil on the West (opposite the lean) was clearly broken upwards, but only for about 12 inches from the trunk. Second, there was a single drip irrigation head right where the roots were pushing up from below, again about 12 inches from the trunk; there were no other emitters in the immediate area of the tree. Third, the soil was visibly saturated on the West and bone dry on the East.

How often was the irrigation system run? Every day for twenty minutes.

A couple of things about trees to keep in mind:

  1. Tree roots have three functions: roots convey water and nutrients from the soil; roots provide storage of sugars and starches; roots stabilize and anchor the tree in the soil.
  2. Tree roots do not "seek out" water. Roots do not have eyes, ears, noses, or any other sensory organ with which to find water at a distance. Roots do, however, proliferate in the presence of water, and only in the presence of water.

The diagnosis was clear: the tree was receiving frequent shallow water in a single small space on the West side of the trunk, and this had resulted in a small root mass; the root mass was probably no larger than 2 feet by 2 feet, probably only 18 inches deep, and predominantly on one side of the tree. The area above that root mass was continually moist and loose. Once the tree reached a certain size and caught the wind just right, over it went.

Palo Verdes are very drought-resistant trees; in this instance, it would have grown more sturdily — albeit more slowly — with no water at all.

The remedy was less straightforward. Once a tree begins to fall, it's difficult to get it back upright, and rarely is this a complete success in the long term. The hard-nosed, unsentimental, and practical response is to remove the failed tree, install a new tree, and re-work the irrigation to avoid a repeat of the same problem. In this instance, we did some judicious pruning to clear the entryway walk and to lessen the canopy weight in the direction of the fall. Next, rather than try to pull the tree back upright, we decided to temporarily support the trunk in its current position and immediately rework the irrigation to begin growing a much wider and deeper root system to support the tree. Any sturdy board with a bit of padding would have worked for a support, but the homeowner wanted the support to look nice, so he promised to build one and get it under the tree that day.

Postscript: A day later the support wasn't in yet, and that evening we were hit with a monsoon-season thunderstorm that dumped nearly an inch of rain in a very few hours. Down went the tree.

The morals of the story:

  • All trees should be watered deeply — to a depth of three feet and as wide as the canopy, or wider — and infrequently;
  • Things move fast in the Desert Garden, epecially when they start to go wrong;
  • Don't let the perfect (or the pretty) be the enemy of the good (with apologies to Voltaire); and
  • You simply cannot say "I told you so" to a man whose tree is laying flat on the ground; he already knows.


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Saturday, July 12, 2008

Mark Your August Calendar

On Friday, August 1st, at 1pm, I will be presenting a workshop on Tree Selection and Planting for the Desert Garden, at the Maricopa County Home and Garden Show. The show is being held at the University of Phoenix Stadium in Glendale, and admission to the workshop is free with admission to the show.

Come spend an hour learning about some of the best trees to grow in the Desert Garden, how to select them, and how to place and plant them. And, as always, bring lots of questions.

Coming up on the calendar: This October is composting month! I will be conducting composting workshops for the City of Scottsdale (October 2), the Gilbert Library (October 21), and the City of Chandler (October 25). I'll post times and locations as we get closer.


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Friday, July 11, 2008

From the Inbox: Coffee Grounds

I received the following question from a correspondent who had recently attended one of my presentations on vegetable gardening:

I have a question about using coffee grinds around my roses, gardenias, etc. We talked about it, but I don't remember if you said how OFTEN we can put coffee grinds out there. Can you help me with that?
M., in Scottsdale, Arizona

Dear M.,
For coffee grounds, I’d go ahead and put them out as often as you like; they won’t harm the plants in anything less than truly massive quantities. You might use a small garden cultivator to scratch them into the soil a bit to aid decomposition and to head off the formation of any water-resistant layer. Coffee grounds are somewhat hydrophobic and in larger quantities can form a barrier to water penetration.

If you produce more than about a cup of coffee grounds each day, you may want to a) seriously think about how much coffee you're drinking; and b) run them through the compost pile before putting them in the garden. Coffee grounds are relatively high in nitrogen (with a carbon to nitrogen ratio of about 20:1, the same as grass clippings), and in our desert conditions much of that nitrogen is lost when applied directly to the soil. Compost is a far more stable product and less likely to result in nitrogen loss. Plus, paper coffee filters can go straight into the compost pile along with the spent grounds, where they will tidily decompose. Littering your yard with undecomposed filters is likely to attract the opprobrium of neighbors.

I hope this helps,


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Wednesday, July 9, 2008

From the Inbox: Fruit Trees and Caliche

From a Correspondent:

My wife and I are fairly new to growing vegetables here in the desert. I've read nearly every book I can get my hands on and noticed a couple things that got me wondering.
1. Is foliar feeding really effective for plants? Seems to me that with the heat so much of what I spray on the plant would get evaporated before the plant has a chance to soak it up. Some of the information I've been able to dig up on the Internet suggests that the plant can get many times more nutrients from it's leaves than it can from the ground.
2. How can I tell if I have caliche without digging down the 4-5 feet recommended by some of the desert gardening books? We plan on planting some fruit trees in our yard this winter and want to give them the best chance for survival, but don't want to just dig down 5 feet unless I really need to.
Chandler, Arizona

Good morning, Tom,

These are both great questions. The answer to both is: it's all about the soil. But since they're from different perspectives, I've answered your first question in a previous post, and we'll tackle the second question here.

When I get a question from a client or a correspondent that includes "fruit tree," "caliche," and "dig down five feet," I know exactly what book they've been reading. It's a great book and very useful for learning about growing fruits and vegetables in the Desert Garden — except in this one instance, where it goes terribly astray. Don't do it!

Caliche is a hardened layer of calcium carbonate that sometimes forms a subsurface water-impermeable layer in some areas of the desert. Where it's present it can be a concern because it can interfere with drainage and can, if shallow enough, prevent tree roots from anchoring deeply in the soil.

As a side note, other soil issues can be mistaken for caliche. In newer developments, we sometime find a layer of clay soil that's been compacted by heavy construction equipment: this is called hardpan. In houses built on former agricultural lands, we sometimes find a layer of impervious compacted soil caused by years of plowing at the same level: this is called plowpan. Either can restrict root and water movement in a manner similar to caliche, but they're not the same thing.

To your question: not only do you not need to dig down five feet deep, but you really shouldn't dig down five feet. It's a very bad idea.

While I'm tempted to just answer your question and tell you what to do instead of a five-foot hole, I'm first going to explain the whys and wherefores. I can't help it.

There was a time when the recommendation for planting fruit and other trees in the Desert was to dig a hole five feet deep and five feet across, and then plant the tree in the hole, replacing a huge portion of the removed soil with organic material such as compost or rotted manure, or wood chips. The idea was that you could get through the caliche layer (if there was one) and also provide the tree with good soil in which to grow.

More recent research has demonstrated that there are two problems with this advice. First, it simply isn't possible to dig a hole large enough to provide "good" soil for the mature root growth of a tree. Consider that an apricot tree, for example, will grow a canopy 15 feet wide and have a mature root area somewhat larger than the canopy. To accommodate the mature root area, you would have to dig a hole 25 feet wide and five feet deep, in the process moving approximately 2500 cubic feet of soil. If you decide to try that, let me know: I want to come watch.

If instead you decide to improve the soil in a smaller area — let's say a five by five hole — one of two things will happen: either the tree will grow roots only into the improved area and thus have a small root area with poor anchoring and consequently be subject to poor development and wind-throw, or the tree will happily send roots out into the surrounding, unimproved, native soil, in which case it was a waste of time to improve the soil in the first place.

The second problem with improving the soil for a tree with organic amendments is that organic amendments break down. All that manure and compost and wood chip will decay and in the process get smaller. And the tree that you've planted on top of all that lovely organic matter will sink. It will sink a lot. It will become — to belabor the point — a sunken tree.

Sunken trees aren't good. Sunken trees collect water in a very small area near the trunk and consequently develop small root systems and become susceptible to rots at the base of the trunk.

A sunken tree also means that your tree is, as above, pretty much growing in native soil. Which means all your amendment was a waste.

So, here's what you do instead of digging a five-foot hole: dig a one-foot-deep hole where you want to plant your tree, about a foot or two wide. Fill the hole with water. If the water drains out completely within about a half a day, then you're all good to go. Let the soil dry a bit (never dig wet soil), then dig out the hole only as deep as the root ball of the tree you're planting, and about three times as wide. Remove the tree from its container, place it in the hole, and back-fill with only native soil, keeping the top of the root ball at ground level (no mounds and no "bowls"). Water it well and them mulch heavily and widely with an organic mulch such as fine chipped bark, keeping the bark slightly away from the trunk.

If the water doesn't drain within half a day, take a soil probe (a piece of rebar or a really long screwdriver) and push it through the bottom of the hole. As deep as it goes is how deep your obstruction is. At that point you can either dig down to try to break through the obstructing layer, or you can try the water test in another part of the yard. If you're fairly certain that the obstruction is at least three feet deep, go ahead and plant the fruit tree anyway; three feet of soil is going to be good for almost any fruit tree. In either case, dig only as deep as you must, and never back-fill the hole with anything other than native soil.

At this point you may be wondering why yesterday I told you to add lots of organic material to your garden soil, and today I'm telling you to not add any organic material to your tree soil. That's because organic material always breaks down, and so it takes multiple additions over a long period of time to make real changes to your soil. In a vegetable garden we can add more material — and new plants — several times during the year and eventually make a lasting change, while in planting a tree it's a one-shot deal. Trees eventually will grow into native soil, and they will be stronger and healthier if they just get used to it from the beginning.

That gardening book you've been reading is full of great information from a much-respected gardening expert, and you can learn a lot from it. Except those pages on caliche and the five-foot hole; just skip over those and we'll pretend it never happened.

I hope this helps,


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Tuesday, July 8, 2008

From the Inbox: Foliar Fertilizers

From a Correspondent:

My wife and I are fairly new to growing vegetables here in the desert. I've read nearly every book I can get my hands on and noticed a couple things that got me wondering.
1. Is foliar feeding really effective for plants? Seems to me that with the heat so much of what I spray on the plant would get evaporated before the plant has a chance to soak it up. Some of the information I've been able to dig up on the Internet suggests that the plant can get many times more nutrients from it's leaves than it can from the ground.
2. How can I tell if I have caliche without digging down the 4-5 feet recommended by some of the desert gardening books? We plan on planting some fruit trees in our yard this winter and want to give them the best chance for survival, but don't want to just dig down 5 feet unless I really need to.
Chandler, Arizona

Good morning, Tom,

These are both great questions. The answer to both is: it's all about the soil. But since they're from different perspectives, I'll answer your first question here, and the second in a following post.

Foliar application of fertilizers pops up every now and then as "the" answer to gardening, sold primarily on being fast. Fast, however, isn't really our goal in home vegetable gardening. If we were really looking for fast, we'd just pop down to the grocery store and load up the cart with produce. That's much faster.

More to your point: I would suspect, though I have seen no studies to back it up, that evaporation would tend to limit the availability of the fertilizer to the plant. And — because all fertilizers are salts — that leaves us with a residue of salts on our plants' leaves, which seems unwise.

On a — literally — deeper level, though, there are greater problems with foliar feeding. First is the name: even though we talk about "feeding"our plants, and foliar "feeding," the truth is we don't feed plants. Plants create 100% of their own food through the process of photosynthesis. Real plant food, despite advertising to the contrary, is made up of sugars and starches created within the cells of the plants. The elements of fertilizer — nitrogen, phosphorus, potassium, iron, sulfur, magnesium, etc. — are simply among the elements that plants use in the creation of their food. They are not food itself.

Which brings us to your next point: while it is possible that plants may be able to absorb many times more nutrients through their leaves than from the ground, I have my doubts about this, having seen studies on both sides. But what we do know to be fact is that plants can absorb from the soil all the nutrients they need. And excess beyond need, is, well, excess.

So, to cut to the chase: gardening, especially vegetable gardening, is all about good soil. And foliar feeding does nothing to develop good soil. Save the money that you might have spent on foliar fertilizer and invest in organic soil amendments instead. Compost is excellent, as is rotted cow manure. Organic soil amendments will add nutrients to the soil, improve water retention and drainage, increase the levels of biotic activity in the soil, probably decrease pH levels — which will increase nutrient availability — and in general be beneficial to your plants.

Spraying foliar fertilizer may give a plant a one-time boost, but incorporating organic materials into your soil at the beginning of every planting season will consistently and continually improve your soil over time. And it's really that improved soil that will give you a good crop of vegetables. If in the future you suspect that you have a deficiency of a particular element — nitrogen, for instance — then side-dress your plants with an organic fertilizer applied to and worked into the surrounding soil. It may take longer to benefit the plant, but it will also have a longer-term benefit to the soil. And that's really the whole secret to growing vegetables in the Desert Garden.

I hope this helps,


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Monday, July 7, 2008

Building Blocks: Summer Harvest

The best part of growing your own fruits and vegetables is, of course, in the harvesting and eating. But when it comes to harvesting the fruits and vegetables that ripen in the Summer heat, a little extra caution is in order.

Conventional gardening wisdom tells us to harvest early in the day, when temperatures are cooler and plants are full of moisture. But right now, when daytime temperatures in the Desert Garden are consistently above 100° and night temperatures are not much lower, "cooler" hasn't much practical value.

For the most part, our fruits and vegetables do just fine in the extreme heat as long as they're attached to, and receiving moisture from, the plant. It's interesting, really: that pepper out in your garden, for instance, may itself have a "body" temperature of 85°, but it's fine. If we think about it though, we realize that the moment we sever that pepper from its stem, it becomes a piece of fruit sitting around at 85°. And if you've ever left fruit sitting out on a warm kitchen counter or, even worse, in the back seat of the car, you know that warm produce deteriorates very quickly.

We can lose a lot of our harvest in that fast transition from growing fruit to harvested produce; what we call "field heat" starts to degrade fruits and vegetables almost instantaneously. I once lost a dozen apples through just leaving them in the basket, figuring they could handle the couple of hours until they became pie; every one of them turned brown on one side in the interval and were unusable.

There are two easy methods for dissipating field heat, and cooling your produce. The first is to simply place the produce in a sink full of cold water until it's cool, and then drain. The second method is to lay the produce in a single layer on a refrigerator shelf; use a single layer with no container so the heat dissipates more quickly. Fill the sink or clear a refrigerator shelf before you head out to the garden to harvest in any quantity, so you can pop the stuff right in. Our tap water is often warm this time of year, so you may need to add a few ice cubes to cool it down, but don't make it freezing. Leave the produce long enough so it's cool all the way through, and then store or use it.

There's an even better harvesting method for use with tomatoes: stand in middle of tomato patch; pick tomato; eat tomato right there and then. Repeat as needed.


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Thursday, July 3, 2008

From the Inbox: Leafcutter Bee Nest Update

Bamboo Bee Nest © 2008

Back in May of this year, I had a number of inquiries about Leafcutter Bees, and posted a note about Leafcutter Bee nests from bee expert Stephen Buchmann (click here to read his response). Corinne, in Paradise Valley, Arizona, kindly sent along this terrific photo to show her new bee nest in action (click the photo to enlarge). Note that it's essentially a collection of bamboo tubes bundled together. The bee has been lining each tube with leaf pieces to create cells, laying an egg and a food supply in each cell, and then capping off the ends with more leaf. A very simple and effective way to host these great pollinators in your yard.


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Wednesday, July 2, 2008

Desert-Adapted Trees

A recent correspondent who wrote to ask about planting "special" trees, has sent along a follow-up question about what kinds of low-water trees to plant. Perfect timing: Summer is the time to learn and plan, and Autumn is the time to plant.

Over the next few days, I'll introduce you to a number of very good desert-adapted trees. To start, take a look at the Desert Ironwood here.


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Tuesday, July 1, 2008

Stop-Action Quince, Part 7

Quince, Week 10 © Tyler Storey

As today is July 1, we can be hopeful that our intrepid quince has survived June Drop; technically, it could still happen, but why dwell on unpleasant possibilities?

In the cooler and wetter Spring pollination season, fruit trees tend to pollinate and set a large number of fruits. As the year progresses and we enter the drier and considerably warmer early Summer months, the trees end up burdened with more fruit than they can handle and they start shedding — dropping — the excess. We walk outside one morning and find the ground littered with half-developed fruit. I know to expect it, but I still find it alarming.

Living plants create energy in the form of sugars and carbohydrates through the process of photosynthesis. Of the many ways we can consider the parts of any plant, one way is to consider the various parts as being in one of two categories: those parts that create energy, and those parts that use energy. Fruits definitely fall into the latter category; fruits are energy sinks, and draw a huge portion of energy from a plant. If a fruit tree has more energy users — fruits — than it can support with its energy producers — leaves and such — then it begins shedding the unsupportable extras; some are sacrificed so that the available energy can go to the survivors.

It's a little bit like when you're running the toaster and the coffee pot and the waffle iron and the stand mixer and the light above the sink all at the same time and the circuit blows. Not quite the same, of course: we don't have to sacrifice the waffle iron for the greater good of the toaster; we just re-set the circuit breaker.

When you see June Drop, don't panic; do be certain that the tree has adequate but not excessive water; and throw the falls on your compost pile, where they will still be of some utility.


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Friday, June 27, 2008

From the Inbox: Planting 'Special' Trees

From a Correspondent:

I live in Oro Valley, Arizona, near Tangerine and La Canada (this info in case there may be a unique 'micro' climate here). My husband and I are thinking of planting about 7 desert trees in the back part of our property. We're thinking Desert Museum Palo Verde and Mesquite — I am not sure which variety (any suggestions there?). When I phoned the nursery, the man who answered told me he had a 'special' going on because he was overstocked – and that NOW ('monsoon season') was the very best time to plant them. He went on to say that the rains would help establish the trees, which makes sense on one level to me, but I thought the very hot summer temps would stress the trees too much. He said no. I'm thinking that the investment of 7 boxed trees plus delivery and planting represents a big investment and I would like to get your input.
Thanks so much for your time.
Oro Valley, Arizona

Good morning Tessa,

I am always leery of overstock end-of-season "specials." Except for donuts; I'm a sucker for day-old chocolate-covered donuts. But boxed trees are — as you point out — a much bigger investment than are stale donuts.

So let's dissect this. First, you're right to be interested in micro-climates in your area. You're definitely in the Desert, but you're also right down-slope from a little "island" of snowy-winter mountain, and the entire area is corrugated with roughly North-South arroyos. In your area, your micro-climate is going to depend on where you are in relation to the arroyo, and on the contours of your property. For the most part, though, it will be more of a cold-season issue.

So on to the trees. Palo Verde and Mesquite are both excellent choices. I am not a big fan of hybrid Palo Verdes such as the "Desert Museum," but it's not a bad choice. For the mesquite, I strongly recommend sticking with the natives, rather than the foreign varieties. The Honey Mesquite, Velvet Mesquite, and Screwbean Mesquite are all excellent choices and hardy in your area. Each has a different form and habit, so look them up to see which fits your plans.

Autumn or Spring is the preferred time for planting trees, especially large boxed trees. You're right about the heat stress. A boxed tree does not have the root system in place to draw the water necessary to support itself once it's in the ground. That's one of the reasons I always recommend buying small trees — 15-gallon or 24-inch box at the largest. Smaller trees of those sizes have roots more in proportion to their canopy size, they undergo less stress in planting, they will establish faster and will catch up with and surpass the bigger boxed trees.

Also consider that a box is a tough place for a tree to grow under the best of circumstances. Now, as the Spring planting season has ended, those "special" trees will have been in the box for a long time. It's more likely that their roots have suffered from heat scald, or that the roots have started to circle the container. Circling roots are always bad — despite our best efforts, they will never "un-circle."

Trees are a long-term investment and their success in the future — even years into the future — depends on planting them under the best possible circumstances.

I would recommend that you wait to plant your trees in the fall. Fall planting means that the trees will put on good root growth in the still-warm soils while suffering less heat stress in the cooling air temperature.

If you have to plant big boxed ones, go to the nursery and select the trees yourself. Find ones with adequate levels of soil in the box, with no circling roots, with a canopy that is not too over-big for the root-ball size, with sturdy trunks, and that have as many lower branches as possible. And try to buy ones that haven't been sitting in a hot box all Summer long. When you plant them, don't prune off any lower branches for at least a year, and don't stake the trees unless it is absolutely necessary. Do be certain to remove the nursery stake that's right up next to the trunk.

Even better, buy 15-gallon trees, dig the holes and plant the trees yourself, and save a bundle of money. You'll have healthier and faster-growing trees, and you can use the savings to buy some nice desert-adapted plants to place under your new trees. And possibly a few donuts.

I hope this helps,


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Thursday, June 26, 2008

Ants and Eggplants

Since posting my article about ants eating the eggplants here at the Ranch, I've had several notes from others having the same issue, ranging from California to Massachusetts. Apparently this isn't as uncommon a problem as we all thought. Considering the geographical range, I suspect this has more to do with the eggplants than it does with a specific type of ant.

I did get an identification of the ants attacking my eggplants from Carl Olson at the University of Arizona, and he seemed as surprised as I was: "Wow, those ants are Solenopsis, and I am pretty sure they are S. xyloni. The looks can be variable but everything I checked points to xyloni. That is crazy, but they are also such aggressive ants when they find food resources."

Solenopsis xyloni is the common Desert Fire Ant, a native to this region and throughout the Southern United States, including California.

So, we know what kind of ant, but now what?

Well, an interesting thing happened here at the Ranch: the ants kept eating the eggplant, but the eggplant, it turned out, didn't seem to mind. I still have a bumper crop of eggplant.

When I first noticed the ants, they were cutting into stems at the terminal growth and in the leaf axils. They seemed not so much to be eating the plant tissue, as they were opening areas to eat the plant "juices," the sap. A fine distinction, perhaps, but as it turns out an important one.

The destruction and cutting of stems was secondary to the ants' activity. Ants, almost by definition, are extremely organized and industrious workers. Had they been setting out to cut and harvest plant stems and tissue, the plants would have been gone in no time. Once ants have their collective mind set to a task, that task gets done.

Instead, the ants were sipping plant juice, so any terminal or flower growth not in their immediate "grazing ground" continued to grow unmolested. Hence my bumper crop of eggplant. I am up to my ears in eggplant.

There's an important gardening and pest-management principle here, and one I've said before: insects are only a problem when they cause damage at an unacceptable level. If our goal is, for instance, to harvest eggplant, then as long as we're harvesting eggplant we don't need to worry about the ants.

For those of you who wrote to me about similar eggplant and ant issues, take a look to see if you're still getting fruit. I'd be interested to hear if your experience is turning out the same.

I hope this helps,


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