Companion planting charts

Matches made in heaven

Companion planting charts help gardeners to plant crops that capitalize on the natural harmonies and relationships that occur between plant species. These charts, available from any number of web sites, nurseries, and botanical books, provide lists of plants that grow well together. Companion planting schemes typically promise a means of pest control, the possibility of increased disease resistance for one or both plants, and more abundant crop yields.

Industrial farmers and suburban gardeners alike can benefit from pairing plants with complementary growing patterns. Common techniques include the creation of green barriers between food crops and the insects that consume them; the use of helpful species to increase the nitrogen content of the soil, thereby reducing the need for chemical fertilizers; and the raising of nurse crops to protect newly sprouted plants. Certain combinations of plants allow farmers to create foodstuffs with maximum time efficiency, such as the combination of soybeans and corn common throughout the entire American Midwestern region.

Although certain plant pairings promote better growth and healthier soil, other combinations can result in unforeseen complications or undesirable competition. Most charts include information on these undesirable pairings, as well.

Vegetable medley

Many techniques and plant combinations already commonly used in gardening for aesthetic purposes could be considered forms of companion planting, although detailed charts also contain more exotic pairings. Nasturtium attracts caterpillars, so planting it alongside or around vegetables such as lettuce or cabbage protects the food crop. The nasturtium acts as a kind of decoy, since the egg-laying insects will gravitate toward it and stay out of the vegetables. Crops that suffer from greenfly and other aphids may benefit from the proximity of marigolds: these flowering plants attract bugs that eat aphids, such as hoverflies.

In a similar manner, the use of plants that produce copious nectar and protein-rich pollen in a vegetable garden can support a population of beneficial insects to control pests. Some insects in the adult form are nectar or pollen feeders, while in the larval form they are voracious predators of pest insects. For this reason, roses are often grown around food plants, attracting a beneficial balance of harmful to helpful insects.

Another movement utilizing companion planting is that of the forest garden, where companion plants are intermingled to create an actual ecosystem, emulating the natural interaction of a multitude of distinct species. This system sacrifices some of the orderliness of a typical residential garden, but produces a lush, wild beauty reminiscent of a true forest.

Fringe benefits

Companion plants provide many services to the plants they support, including:

• Flavor enhancement. Some plants, especially herbs, tend to subtly improve the flavor of other plants around them.

• Investment insurance. Multiple plants in the same space increase the odds of some yield being given, even if one category encounters catastrophic failure.

• Level interaction. Plants that grow on different physical levels in the same space can form ground cover or work as a trellis for another plant.

• Nitrogen fixation. Some plants naturally trap nitrogen in the soil, improving conditions for future crops.

• Pest suppression. Some plants naturally repel insects, nematodes, or fungi through chemical means, a protection that extends to other plants in close proximity.

• Positive hosting. These plants attract or house insects or other organisms that benefit plants, such as ladybugs, bees, or some desirable species of nematodes.

• Protective shelter. One plant type may serve as a windbreak, source of shade from noonday sun, or other physical aid for the growth of another.

• Trap Cropping. These plants draw insects away from plants commonly eaten by humans.