Vegetables grow best in loamy soil, allowing plenty of drainage and contains high soil porosity so roots can access oxygen. Clay soil by temperament has poor soil structure that compacts easily, limiting oxygen and water flow through the soil. Water may stand on the soil surface, not able to penetrate the dirt, or the dirt only stays wet, which may result in root rot. Vegetables like cabbage, broccoli and brussels sprouts do well in heavy dirt, but frequent, heavy applications of organic matter are required before planting vegetables. Start amending the dirt annually before planting to get best results.
Cover the ground with 4 inches of organic humus material in spring one year before starting a garden at the following spring. If grass is growing in the garden place, leave the grass in position because this is extra plant material to increase the dirt. Materials you may add include aged manure, grass clippings, straw, sawdust, shredded bark, and leaves or leaf mould. For best results, use an equal amount of green and brown materials to prevent hydrogen and hydrogen imbalances in the soil.
Add 3 to 4 inches of finished compost over the 4-inch layer of humus materials. Compost is important because it’s already broken down, providing stabilized construction to the soil. The humus materials decay quickly and have to be added frequently before serious alterations happen, but compost has an instant impact on soil structure.
Scatter 2 inches of coarse sand above the compost layer to increase porosity and drainage from the soil. Fine sand particles mixed with clay produces a cement-like mixture, which means you have to add only coarse sand into the clay.
Broadcast a complete fertilizer, such as 12-12-12, that contains nitrogen, phosphorous and potassium, in the soil at a rate of 2 pounds per 100 square feet or roughly 3 ounces per 10 square feet of garden area. Fertilizer is particularly important whether the brown and green humus materials are imbalanced.
Till the layers of soil amendments to the top 8 to 10 inches of the native clay soil using a rototiller. Wait until the soil is dry before attempting to till the soil because wet clay dirt forms big clods that are tough to break up after they dry.
Implement extra layers of humus materials, compost and coarse sand about once monthly over the summer, and until the materials to the top 8 to 10 inches of dirt. Repeated applications are not required, however, the speed of progress in clay dirt is consistent with the speed of application of soil amendments.
Broadcast seed to get a cover crop in mid to late autumn at a speed of about 1/3 pound for each 100 square feet of garden space. Alfalfa, barley, rye and clover are common cover crops you may plant. Permit the cover crop to grow naturally, and also leave it untouched over winter. Cover crops protect the ground over winter and supply extra humus to improve soil structure.
Add about 2 inches all finished compost, aged manure and coarse sand within the cover crop. These materials are optional, but only further enhance the clay dirt.
Till the cover crop, compost, manure and sand to the top 10 inches of the soil in late winter to early spring after all danger of frost has passed and when the dirt is dry.
Break up any dirt clods using a spading fork. Allow about 2 weeks to the dirt from the clods to dry. Till the soil a second time after the clods have dried.
Rake the ground smooth, using a bow rake and leaf rake.
Utilize the dirt into straight lines, using a garden hoe to dig furrows as deep as the root ball of the vegetable transplants, typically no more than 6 inches. If you’re going to direct sow seed into the garden, then follow the specific planting directions for each plant type. Seeds are generally planted to a thickness of 1/2 to 1 inch; refer to your own seed packet for planting depths.
Loosen the dirt between planting rows using the rototiller, being careful to not disturb the plant origins. Use the garden hoe if you cannot browse the tiller between rows without damaging your vegetable plants. This keeps the dirt loose and prevents compaction. If possible, place a couple of stepping stones at the row to help limit foot traffic in the garden, that can also compact the dirt.