by Margie Siegal, Alameda Backyard Growers
Originally published in the Alameda Sun, April 11, 2019
Many people don’t think too often about the dirt beneath their feet, but the dirt that covers most of the Earth’s dry land makes growing things possible. For those of us who want to have healthy and happy gardens, the composition of that dirt — usually called “soil,” in this context — is vitally important.
In many areas of Alameda, the native soil was once a sand dune, and thus does not provide a lot of nutrition for plants. Water drains through it almost immediately. Other areas are more like the rest of the East Bay, and are heavy on clay, which is hard to work and even harder for a plant’s roots to grow through. The cure for both conditions is to add a lot of organic matter: compost, composted animal manure (from chickens, horses or cows) or mulch.
Compost is the final product left after vegetable material — grass clippings, leaves, kitchen scraps — finishes breaking down. It does not have an objectionable odor and will not damage new plantings. Adding lots of compost to soil will make it more workable, add nutrition for plants and help it hold water. Making compost is not difficult and keeps a lot of waste out of the landfill. Finished compost is often available for free at Ploughshares Nursery at 2701 Main St. in Alameda.
Mulch is spread on top of the ground and can take the form of compost, composted animal manure, wood chips, leaves or straw. Spreading mulch over the soil will aid in water retention, which is important in the Bay Area’s dry summers. Organic mulches will break down sooner or later, but will add to soil condition and fertility. (Alameda Backyard Growers (ABG) suggests avoiding plastic sheeting, as it is a petroleum product and can interfere with soil breathability and drainage).
Interested in more information about soil and how to improve it? There are many local resources. Ploughshares Nursery often has classes, as does the Berkeley Ecology Center and Pollinate Farm and Garden in Oakland.