From a correspondent:
I have a question about soil and compost: Can I use potting soil and regular dirt, mixed, instead of compost? If not, can I purchase compost? Also with tomato plants when they start to bear fruit, should I wean out leaves and bottom shoots ? I have three plants that I started with, and they are starting to bloom and bear fruit.
Bob, Casa Grande, Arizona
Good morning Bob,
Great questions, and both issues are important in the Desert Garden.
First to the soil and compost. Whenever possible, the foundation for your vegetable garden should be your native soil. Real soil, the kind we buy with the house, is chock full of desirable minerals and other plant nutrients; the minerals we eat in our vegetables come from the soil in which they grew. Potting soil doesn't have those good qualities.
So our goal always is to amend out native soil with compost or other organic material, rather than to use potting soil (besides, by volume, potting soil is expensive!) And don't be tempted to mix potting soil in as a substitute for compost; it really isn't the same thing and it won't do a good job. If you're not yet making your own compost, you can buy it in bags or in bulk. Mix it onto your native garden soil, and you're on your way.
Now for the tomatoes: make life easier on yourself and on your tomatoes, and don't pinch out leaves and bottom shoots. In other climates, gardeners often pinch out extra tomato shoots and leaves to open up the plant, promoting ripening and light in the interior. Here in the Desert Garden, we want to do just the opposite.
Very soon now, our weather will be steadily hot and sunny, and that's hard on the tomatoes. If you leave the leaves and shoots, they help to form a shady and cooler canopy that will help to protect the ripening fruit; that's one of the best ways to ensure good tomatoes in the desert.
I hope this helps,