E:\sjef\uvi\publications\gf6-nec.PDF GARDENERS FACTSHEET NO. 6 FEBRUARY, 1979 Revised Nov. 1994 HOW TO PREPARE YOUR OWN COMPOST Dr. John M. Gerber Vegetable Specialist Plant materials, animal manures and soil microorganisms are combined in a pile to create valuable compost. Compost is partially decomposed organic material which, when added to the garden, improves both the physical structure and fertility of the soil. Annual additions of compost and other organic materials will provide benefits that may not be immediately apparent but improve the soil over time. As partially decayed organic matter continues to decompose in the soil, fine soil particles are collected together into larger crumb-like masses. These larger particles will not pack as close together as smaller particles. This action will improve drainage and aeration and will “lighten” heavy clay soils. Sandy, well-drained soils made up of primarily large size soil particles are likely to dry out rapidly and cause plants to wilt. Additions of organic matter such as compost will increase the ability of sandy soils to retain moisture and nutrients. As compost decomposes in the soil, plant nutrients are slowly released to the plant. Although this will not supply all the nutrients required for optimum growth, it will help supply most of the plant nutrients required in small amounts (trace elements). Nutrients required in large amounts, such as nitrogen, phosphorus and potassium, should be supplied in a concentrated form, such as 10-10-10 fertilizer for maximum yields. However, the gardener who is not concerned with maximum production can supply adequate nutrition using only manure and compost. Annual applications of 4 bushels of manure per 100 sq. ft. plus generous amounts of compost will produce adequate yields. THE PILE All plant and animal material will eventually decay if it is exposed to warm, moist conditions. The compost pile provides those conditions so that the microorganisms can rapidly decompose organic materials.