How to Condition Clay Soil to Plant Annuals & Vegetables

It takes time to amend clay soil, but the end results are worth the effort.

If you are a keen gardener cursed with a yard full of clay soil, you have three choices: stick to trees and plants that thrive in clay, relocate to a suitable growing area or exercise patience and commit to a couple of years of work reconditioning your garden. In the meantime, establish some raised beds containing rich soil. Grow your favorite annuals and vegetables in these beds while you apply a few simple steps to the rest of the yard. This quality soil will eventually work its way into the ground below and improve the surrounding clay naturally.

Things You'll Need

• Well-rotted manure
• Green vegetation
• Leaf mold
• Peat moss
• Sawdust
• Bark
• Wood chips
• Cover crop

Instructions

1. Avoid overworking the clay with excessive tilling. Never work the soil while it's wet. Create permanent paths and avoid compacting the rest of the garden with unnecessary foot traffic. Clay is highly susceptible to compacting. Once compacted, drainage is reduced, moisture retention increases and the compacted clay gums up tillers and hand tools, making the soil almost impossible to work.

2. Add organic material to the soil at regular intervals. Use material that composts quickly, such as well-rotted manure, green vegetation, leaf mold and peat moss. Work 3 to 4 inches of the organic material gently in to a depth of 4 to 6 inches without compacting the soil.

3. Plant vegetables and annual flowering plants in the beds while you wait for the clay to assimilate the compost. Once it breaks down, work more organic material into the soil.

4. Water sparsely to avoid moisture buildup from poor drainage during the first year or so. Your garden beds will improve steadily, and within two or three years, vegetation will flourish in the dark and crumbly soil you have helped to create.

5. Add slower-composting organic cover material to unused areas of the garden. Stick to slow-composting sawdust, bark and wood chips, but do not try to work the material into the ground. Once the surface cover starts breaking down, use some of it for mulch in your vegetable and flower beds, and add more cover material to the rest of the garden periodically to complete the cycle. Be patient and allow the added ground cover to decompose and work its way into the soil naturally.

6. Grow cover crops, such as borage, hairy vetch, clover and similar vegetation, during colder months when vegetables and flowers are harder to grow. These cover plants put down a network of roots, which helps to amend the soil naturally by increasing aeration and adding nutrients during the colder months. Once warmer weather arrives, work all the plants back into the soil and start a new growing season.

References

• Gardening Know How: Improving Clay Soil in Your Yard
• Cornell Department of Horticulture: Soil Basics