Fertilize the natural way

Compost is a mixture of partially decomposed plant material and other organic wastes. It is used in the garden to amend soil and fertilize plants. The chief advantage of compost is its ability to improve soil structure. Good garden soil is loose and has a high water-holding capacity with adequate drainage. Adding compost to heavy clay soil improves drainage by improving soil structure. Compost also absorbs water and improves the water-holding capacity of sandy soils. To conserve moisture or develop a xeriscape (a landscape requiring little water), it is essential to have soil with good water retention.

Stable and cured compost has its greatest value when rototilled directly into the soil. One cubic yard of compost covers 108 sq. ft. at three inches, 216 sq. ft. at two inches, and 324 sq. ft. at one inch. The rule of thumb is to spread compost no more than one-third the depth of the rototiller. A one-inch layer of compost should be tilled in thee inches, a two-inch layer tilled in six inches, and a three-inch layer tilled in nine inches. Making two or more passes with the tiller helps blend the compost with the topsoil and break up any clumps of material.

Stable compost can be blended into soil mixes and is suitable for most outdoor planting projects. When used as an outdoor planting mix, it is typically mixed with other ingredients such as peat moss, shredded bark, sand, or loamy topsoil. Mixing ratios vary, but 10% compost is considered to be a minimum, 30% optimum, and 50% maximum in planting shrubs and trees.

In addition to improving soil structure, decomposing compost will slowly release plant nutrients. Compost will not, however, provide all the nitrogen that highly productive crops require. Organic gardeners can supplement generous compost applications with manure to produce good yields without the addition of chemical fertilizers.

Finished compost is dark brown, crumbly, and is earthy-smelling. Small pieces of leaves or other ingredients may be visible. If the compost contains many materials which are not broken down, it is only partly decomposed. Adding partly decomposed compost to the soil can reduce the amount of nitrogen available to plants. The microorganisms will continue to decompose but will use soil nitrogen for their own growth, restricting nitrogen availability to plants growing nearby. Allow partly decomposed compost particles to break down further or separate them out before using compost around growing plants. Or add extra nitrogen (such as in manure or commercial fertilizer) to ensure that growing plants will not suffer from a nitrogen deficiency.

Making and using compost allows the gardener to recycle garden wastes and reduce the burdens of trash disposal.