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 Soil
Soil is a complex living system made up of minerals, organic materials, water, and air. Soil supports all life and in its self is a product of living things. Physical properties such as soil texture and soil structure are determined by the amount of organic matter, drainage conditions, and oxidation or weathering.
Most soils in the United States are well suited for vegetables and flowers. There are hundrens of kinds of soil, each different from others in color, depth, size, and arrangement of the individual sand, silt, and clay particles, mineral composition, and content of organic matter.
A good soil is 50 percent solids and 50 percent porous space. Great soil has room for water,air, and plant roots.
Basic soil types
Clay soil. A clay soil is composed of particles that are less than 1/31750 of an inch (1/200 mm) in diameter. These minute particles pack together more closely than larger particles and have a greater total surface area. Clay soil can hold more water than other soils. It often drains poorly, but drainage can be improved by the addition of organic matter to break up the clay particles. If you try to work with a clay soil when it's wet, you'll compress the particles even more closely; then, when the soil dries, you'll be left with a surface something like baked brick or concrete. Properly managed, however, clay soils can be the most productive of all.
Sandy soil. A sandy soil is made up mostly of particles that are over 1/3175 of an inch (1/20 mm) in diameter. They are much larger than clay particles and irregular in shape, so they don't pack as closely together as clay particles. Because they have less total surface area, these larger particles hold less water than smaller particles and are much more porous. Sandy soil drains like a sieve, but can be improved by the addition of organic matter, which helps retain moisture and nutrients.
Silt soil. In a silt soil the size of the particles is intermediate — between clay and sand. Depending on the size of its particles, a silt soil can act either like a clay soil or like a fine sandy soil. Silt consists of small, gritty particles that can pack down very hard, and it's not very fertile. Silt soil is often found on top of heavy clay, which slows or stops drainage.
Loam. Loam is a mixture of clay, silt, and sand particles. A good garden loam is something to cherish, particularly if it also contains a heavy supply of organic matter. All soil improvement is aimed at achieving a good loam — when you add organic matter or make other improvements to your clay or sandy soil, you're trying to provide the type of loam that lucky gardeners have without all that extra work. | |
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| Improve Your Soil |
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Moisture
Soil life perfers evenly moist soil. Soil texture and stucture must be able to ensure good drainage. |
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Earthworms
Earthworms dig up to 6 feet deep in good soils. They increase soil aeration and drainage. Night Crawler (Lumbricus terresris) are powerful composting machines, they break down organic matter to pure humus. Earthworms do more to improve soil structure than any other burrowing organisms. | |
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| Soil Amendments |
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Material
Compost, Manure, Chopped leaves, Sawdust, Peat moss, Hay, Straw, lawn clippings, and fine wood chips. |
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Value
Amendments work best if you blend them into the soil in fall. If materials are well decomposed, you can mix them in shortly before planting.
Microbes will scavenge much of your soils existing nitrogen as they break down carbon. Added nitrogen will help speed along decomposition. | |
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Mulching the soil is an important gardening technique.
Mulch helps control soil temperature. When summer heat raises the soil temperature too high, plant growth stalls. A layer of organic material will cool the soil several degrees.
Mulch also discourages weeds, which compete with seedlings for soil moisture and nutrients. By covering the soil, mulch prevents weed seeds from germinating and protects the soil from compaction by rain and hot sun.
Mulch helps retain moisture by blocking evaporation from the soil surface. The spongy humus is organic mulch also absorbs rain, reducing waste through runoff. At the same time, prevents splashing of soil-borne disease pathogens from the soil surface onto plant leaves.
Decomposing organic mulch helps keep soil alive. As the mulch breaks down, it contributes humus, which is teaming with microscopic life. These organisms-along with earthworms-process soil nutrients.
pH do you really need to test
As useful as it is, a pH test isn’t always necessary. The pH needs of most garden plants tend to fall into the mild to moderately acid range. Because moderately acid soil predominates over large areas of North America, soil pH readings aren’t necessary for selecting landscape plants. Trees, shrubs, and perennial plants that are native to an area are already adapted to the prevailing pH. This is one reason why native plants are so highly regarded. Throughout the country, local nurseries and garden centers carry plants that are appropriate to the soil conditions in their region. You also can find out which plants thrive in your area by noting successful gardens in the neighborhood.
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