University of California
UC Master Gardener Program of Sonoma County
Soil and Composting
Soil health and fertility underlie success in our food and ornamental gardens, but not all soils are ideal for productivity. In many locations of Sonoma County, heavy clay predominates while loose sandy soil is found in coastal areas as well as in isolated pockets inland. Some home gardeners find that construction activity brought in fill material that nearly defies being called soil.
Faced with the need for soil improvement and maintaining nutrients, gardeners are advised to work with the physical texture of the material at hand and make adjustments to its structure, improving fertility at the same time. How? By adding compost, compost, compost!
- Composting converts complex organic residues into nutrients that are slowly released into the soil as simpler forms needed by plants.
- Plant residues such as leaves, grass clippings, manures, chipped and shredded wood, as well as food wastes, paper, and cardboard are broken down by numerous insects and microorganisms.
- The process may be fast-acting when ingredients are fresh, aerated and moist, balanced and tended; or decomposition may occur over long periods when organic materials are left on their own.
- Eventually, all organics decompose but the end result—compost—is such a key ingredient in gardening that rapid or short-term production is often the most desired ingredient in successful gardens.
- Gardeners often focus only on the above-ground results when soils are improved, but the below-ground results are the key to success of all plants.
- Presence of adequate organic matter—especially compost—affects soil structure by loosening clay particles, binding sand, increasing aeration and drainage while, at the same time, enhancing water-holding capacity.
- Organic materials continue to feed a vast and unseen ecosystem of fungi, bacteria, and other microorganisms as well as many beneficial insects, worms, and other life forms.
- It is this working population that keeps soil healthy and filled with nutritious elements.