Organic Gardening, a type of gardening in which only naturally occurring materials are used in all the phases of plant growing—including soil improvement, fertilizing, and pest control. Organic gardening is practiced both by home gardeners and by commercial farmers. The organic foods produced for commerce undergo a minimum of processing and are largely or totally free of chemical preservatives and other additives. They are sometimes called health foods.
Organic gardening is essentially the same type of gardening as that practiced before the advent of manufactured chemical fertilizers and pesticides. The revived interest in organic gardening is in large part due to the growing concern about polluting the environment—and harming the body—with pesticides and other chemicals. It is also argued that organically grown foods are more nutritious than those subjected to commercial processing.
Organic gardeners use compost or manure to fertilize the soil and improve its structure and rely on earthworms to condition the soil. The gardeners add nutrients such as nitrogen, potassium, and phosphorus, but only from natural sources. For example, nitrogen is supplied by hoof and horn meal or fish meal, potassium by granite dust or potash rock, and phosphorus by bone meal or finely ground phosphate rock.
Weeds are pulled rather than eliminated by chemical weed killers. Their growth may also be inhibited by frequent cultivation or the application of mulches, such as straw or hay, around the bases of the desirable plants. Instead of using chemical insecticides to control pests, organic gardeners prefer to use natural predators, such as birds and certain beneficial insects (such as ladybugs and praying mantises). Other measures include the use of botanical insecticides, such as pyrethrurm and ryania, derived from roots or foliage of certain plants.