If you have heavy clay soil, you understand the frustration of adding copious amounts of organic matter to condition the soil, only to have it swallowed whole by the ground and have it revert back to slippery, sticky clay. It seems like a never-ending battle.
To paraphrase an old saying, "If you can't beat it, join it." Accept the fact that you have clay soil (it's geologically undeniable), and roll with it.
One of the best ways to improve clay soil is to fill it with plants that thrive in heavy soils. These "clay busters" have strong roots that are able to plow down through the clay soil and spread out. These growing roots churn through the soil, loosening it up and creating pockets of air, allowing water and nutrients to filter down through the soil to nourish the roots. The plant grows bigger, sends out more roots, and conditions the soil even more with each passing season.
Some of the most popular plants that are known to conquer clay include Asters, Cannas, Coneflowers, Coral Bells, Coreopsis, Daylilies, Hosta, Liatris, Monarda, Russian Sage, Sedum, and ornamental grasses. Your clay soil can be improved just by growing a beautiful blooming garden!
Clay soil can be amended with organic materials like bark, manure, leaf mold, compost, peat moss and sawdust. (Gypsum and builder's sand can also be used, but only after the organic matter.) Spread three or four inches of this organic matter on the bed, then rototill, fork or dig it to mix with existing soil to a depth of 12 inches or more. Repeat this process consistently every fall, and over time, the bed will become more fertile and friable. Soon you'll be growing whatever plants you choose, in addition to the "clay busters."