The most important element of any successful garden is the soil. Soil is composed of clay, loam, sand, or a combination of all three. Clay soil is nutrient rich but lacks easy drainage. Loamy soil is considered ideal because if retains some moisture but doesn’t let plant roots get soggy. Sandy soil doesn’t retain water at all.
Amendments for Clay Soil
In the case of clay soil, you want to break apart the molecules that are holding it together. You can till or dig down about 12 inches and start adding sand, well-rotted (at least 1-2 years old) manure, commercial compost, shredded leaves, grass clippings, and/or sand. Mix this in well and wait a few days to see if you’ve loosened it up enough. Buy a few extra bags of untreated mulch, poke a few holes in the bag, and let it sit over the winter. It will be decomposed enough to make a great amendment for clay soil.
Amendments for Sandy Soil
In the case of sandy soil, you want to add enough material so that the water is retained better and it contains enough nutrients. Add well-rotted manure or compost (including grass clippings, humus and leaf mold to help improve the soil the fastest). Some commercial soil mixes contain peat, so mix it sparingly in with natural materials as it can increase the salt levels in sandy soil and it can build up to levels that will be damaging to plants.
The Lasagna Method
The easiest way to work with bad soil is to ignore it and build a garden bed on top of it. The Lasagna Method uses layers of natural green and brown material to build up the garden rows about 18-24 inches high (deep enough for most vegetables) and about 18 inches wide. As the materials break down they form the most nutritious soil you can have and you don’t walk on the beds so they never get compacted. See this chart for a list of materials to layer. You can build up the soil in a garden bed or a raised bed.
I have built my lasagna beds and planted them right away with success. Just add some good bagged soil between the layers and on the top layer. The layers will compost quickly and plants will thrive.
Here’s how to do it.