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Environmental Horticulture (Gardening)

Improving Your Soil

Tilling your garden correctly preserves the soil and its fertility, enhancing the absorption of rainfall and protecting local streams from run-off sediment.

Gardeners often wonder whether to do the plowing or tilling in the spring or in the fall. Working the soil in fall is far more beneficial than traditional spring plowing. It allows earlier spring planting, since the basic soil preparation is already done when spring arrives.

The turning under of large amounts of organic matter is likely to result in better decomposition when done in the fall, since autumn temperatures are higher than those of early spring, and there is more time for this process to take place. Insects, disease organisms, and perennial weeds may be reduced by killing or inactivating them through burial or root exposure to harsh winter weather. Also, snow is trapped between the hills of roughly-plowed soil, so more moisture is retained than on flat, bare ground. Incorporation of limestone or rock fertilizers in the fall gives them time to interact chemically with the soil and influence spring plant growth.

Fall plowing alone is not recommended for hillside or steep garden plots, since soil is left exposed all winter, subject to erosion when spring rains come. For these areas, a winter cover crop is grown to improve soil and prevent erosion. Till in the fall to prepare the soil for seed, and in the spring turn under the green manure. Spring plowing is better for sandy soils and those where shallow tilling is practiced. Generally, most gardens must be lightly tilled in the spring to kill weeds and smooth the soil for planting.

An alternative to standard procedures is minimum-till gardening, also known as conservation tillage. This method is ideal for transplants to the vegetable garden.

  1. In the fall, prepare the soil for cover crop seed by tilling under summer crop wastes. Remove tomato vines and corn stalks to make tilling easier.
  2. Plant a combination cover crop of rye-hairy vetch (2 lbs. of winter rye grain and 3/4 lb. of hairy vetch per 1000 square feet. The rye, a non-legume, provides the mulch for spring planting. Hairy vetch, a legume, contributes beneficial nitrogen to the soil. The vetch seed must be coated with a Rhizobium inoculant prior to seeding to insure nodulation with nitrogen-fixing bacteria.
  3. In the spring, use a scythe or string-line trimmer to cut the crop cover to a manageable level. Rake the cover crop to the side of the area to be planted and save. Use a lawn mower to completely trim to the ground.
  4. A week later, mow the area again. Now your area is ready for planting. Dig a hole for each plant, large enough to accommodate for root spread. Pull weeds in the surrounding area including cover crop roots. Water in the plants with a water-soluble fertilizer according to directions or, if available, put a quart of compost in each hole with the plant. Mulch the entire area between plants with the clippings reserved from the week before. Leave 6 to 8 inches of space around the base of plants to allow the soil to warm up.
  5. Some additional mulch may be needed for proper weed control. Use grass clippings or leaves saved from the previous fall. If weeds appear, pull them by hand. If hoeing is needed, try to keep the blade underneath the mulch layer and disturb as little as possible.
  6. This process is repeated the following fall to continue minimum-till gardening. You may want to experiment with small plots rather than your entire garden.