In Your Garden

Building Your Soil

by Laurie Cohen
an Diego is a reclaimed paradise. We can see that when we travel to undeveloped parts of town and look at the native soil often a hard red clay or a mass of river rock and decomposing granite. It is a challenge for most of us gardeners to build the soil to the exact needs of our chosen garden plants. It often requires a scientific mix of humus, sand and organic matter. What the typical organic gardener needs to amend their garden with often depends on the condition of the original soil.

Often, when homes were built, the developers cleared away the native topsoil to level the sites for construction. What is left is a subsoil of limited capacity, but with good potential. When plants are grown in that soil, without amendment, the results are often discouraging. Amending our garden soil is a national pastime. Many places sell soil amendments to help the gardener grow the best crop they can.

When we look at nature, we notice the constant supply of dead, decomposing material littering the ground. This is the way the soil is constantly replenished. The composting of leaves and grass and non-animal kitchen wastes in our gardens results in the most useful organic material that can be added to our soil. The needs for other amendments vary, but can be determined by soil testing. Organic content is the most important feature. Research shows that compost can be the single most effective soil additive for strong growth and disease resistance.

Organic compost is sold by the bag or truckload from reputable suppliers if you cannot make enough of your own. If you purchase large amounts of soil amendment make sure you receive a list of ingredients. Some suppliers may try to sell useless amendments that have no value in our gardens.

Do you or your neighbors bag the grass from mowing the lawn, and rake the leaves and trimmings just to bag and throw them away, too? How many times a year is it necessary to use fertilizer to keep the lawn and shrubs healthy and green? The secret of a well-nurtured organic yard and garden is to let the natural process of decomposition take place. Leave some of the grass cuttings on the lawn for added nitrogen and compost the rest with the leaves to make your own soil amendment. You may find the reduced costs for fertilizers a pleasant surprise. Compost is not a cure all for everything you grow, and the careful use of an organic fertilizer may be necessary, but it is the basic building block of the best soil you will ever have.

There are many good books and periodicals available to home gardeners describing the particulars of building good soil. Testing the soil for basic nutrient needs can initially be expensive, but it is invaluable for determining soil deficiencies if there is a growth problem. Joining an organic gardening club can put you in touch with other gardeners and from them you can get regional advice for your garden problems, as well as share in your successes. Good gardening!

Laurie teaches free organic gardening classes from her Clairemont backyard and is forming the Clairemont Organic Gardener's Club. Call her at 270-1490, or e-mail her at