# Facts About Loam
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Soils
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Loam is composed of three main types of soil: sand, clay and silt. Sand feels gritty because it contains the largest particles. It drains water quickly but is easy to work with and aerates easily. Clay particles are far smaller and stick together easily, forming clumpy balls when damp. Because clay packs down, it holds water, preventing air penetration, and is difficult to work with. Silt particles are sized between sand and clay. They feel smooth and can pack down like clay, though not as tightly. They have properties between sand and clay.
Composition
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Loam contains from 7 to 27 percent clay, 28 to 50 percent silt and under 52 percent sand. If these substances exist in roughly equal proportions, the soil is properly called loam. Other proportions can turn the classification into sandy loam, sandy clay loam, clay loam, silty clay loam or silt loam. Good loam shows none of the extreme characteristics of its composite particles. Instead, it drains well, yet holds moisture and aerates easily. It is ideal for many types of plants.
Humus
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Humus is the stable part of decaying organic material. Loam is inorganic. For it to become a suitable medium for gardening, it requires an organic component, which is supplied by humus. This substance increases the ability of sandy soil to retain moisture, loosens clay to make it easier to work with. Humus adds nutrients and encourages the growth of bacteria that can process the nutrients into something usable by plant roots. The most common source of humus is compost. For those in rural areas, barn bedding also contains humus.
Plants
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Several alpine plants do well in loam. Silver alyssum, which is actually yellowish, grows up to 15 inches. Rock asters, which prefer cooler climates and grow slowly, have purple and yellow blooms. Several species of blue irises also prefer loam, including the crested iris. vernal irises and dwarf Crimean iris. Roses do well in loam, though actual growth requirements depend on species. In loam or sandy loam soils, they need at least three to six inches of fully decomposed composed. Clay loam soils will require more aeration and drainage, which can be provided by at least three inches of expanded shale and three inches of compost. Vegetables prefer sandy loam soil because of its drainage with toppings of humus because of the organic matter.
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