Ideal garden soil should be loose, deep and crumbly. It should drain well, water should not stand on top after rain and contain plenty of organic matter. Good garden soil will deliver the right mixture of air, water, and nutrients to grow a large root system and strong, productive plants. Vegetables and other plants will grow satisfactorily with a wide range of soil types from sand to clay if certain steps are followed for overcoming their basic short-comings.
Begin preparing the soil by removing all plant material from this year's garden. Dead roots, stems and foliage can harbor insects and diseases that emerge in the spring to infect next year's garden.
Soil testing can provide important information to make decisions concerning:
- How much lime to use in lawns, vegetable or flower beds.
- How much fertilizer to use on lawns, vegetables, flowers, and shrubs.
- How to adjust the soil pH for optimum growth of acid-loving plants such as azaleas and rhododendrons.
- How to apply soil amendments and fertilizer to improve soil quality.
- Nutrients that are lacking or in excess in the soil.
- Amount of lead or other metals in the soil.
Clay soils have the ability to hold moisture well and usually contain more nutrients than light soils. They dry slowly in the spring so early planting of crops is not possible. Water penetration is slow so irrigation water often runs off instead of entering the root zone.
Sandy soils are easy to work but have low water holding capacities, so plants may suffer from moisture stress in hot weather. Nutrients may be lost as irrigation water moves downward through the soil.
These almost opposite drawbacks of both soil types can be corrected by the same technique-adding organic matter. Fine clay particles can be physically separated by coarse organic material. Nutrient and water holding qualities of sandy soils can be increased. As the organic matter breaks down, its components continue to have soil improving characteristics.
Begin by incorporating 2 to 3 inches of organic matter 6 to 8 inches deep. This application will not last forever and you should plan to add about 2 more inches each year. With heavy soils, you’ll need 2 or 3 years to see much of an improvement. Summer mulching or compost addition will be helpful.
When the soil has dried and warmed sufficiently, spade or rototill to a depth of about 6–8 inches. Garden soil doesn’t need to be “flour-fine.” Leave marble-sized particles and crusting will not be as severe as with over prepared soil. You’ll need to use a rake to pulverize clods. Level and compact the soil for a firm seedbed. The final soil surface should be as level as possible for uniform water penetration.
Additional Resources
Rutgers Univeristy - How to Have your Soil Tested
University of Minnesota - Organic Matter Management
Utah State University - Preparing Garden Soil
University of Maryland - Prepare Your Soil
Alabama A&M and Auburn Universities - Raised Bed Gardening
