Loam is considered to be the most desirable medium for growing crops and many types of plants and grasses. Loam is considered ideal for gardening and agricultural uses because it retains nutrients well and retains water while still allowing the water to flow freely. This soil is found in a majority of successful farms in regions around the world known for their fertile land. Loam soil feels soft and rich and is easy to work over a wide range of moisture conditions.
Loam is soil composed of sand, silt, and clay in relatively even concentration (about 40-40-20% concentration respectively). Loam soils generally contain more nutrients and humus than sandy soils, have better infiltration and drainage than silty soils, and are easier to till than clay soils. Loams are gritty, moist, and retain water easily.
Different proportions of sand, silt, and clay give rise to types of loam soils: sandy loam, silty loam, clay loam, sandy clay loam, silty clay loam, and loam. A soil dominated by one or two of the three particle size groups can behave like loam if it has a strong granular structure, promoted by a high content of organic matter. However, a soil that meets the textural definition of loam can lose its characteristic desirable qualities when it is compacted, depleted of organic matter, or has clay dispersed throughout its fine-earth fraction.
Many gardeners complain of their garden soil being compacted and/or poorly drained. Good news is, just about any soil, even compacted clay, can me modified to loam by adding in good amount of organic matter, such as compost, animal manure, cover crops or organic mulch materials. For example, in a vegetable garden this can be done each year as the soil is worked. It may take several years, but eventually the soil compaction will be improved. Adding sand only can help, but it's the organic matter that offers the best advantages, including increased water and nutrient hold capabilities, and improved aeration as well.