Companion Planting

Companion planting is a system of growing different types of plants in a close proximity, so that they can assist and benefit each other. The idea of companion planting dates back to ancient Romans. One classical example of this system is the 'Three Sisters Technique', pioneered by the native Americans. They used to plant corn, pole beans and squash together. The cornstalks acted as poles for the beans to climb, beans fix nitrogen which is used by corn and squash, squash covers the ground, thereby preventing weeds and retaining the moisture in the soil. The prickly hair of the squash also helped in deterring pests. The same technique was used in cottage gardens, attached to the English cottages, where both ornamental and edible plants were planted together.

As it is evident from the 'Three Sisters Technique', companion planting is beneficial in many ways like pest control, pollination, providing nutrients, support, shelter, flavor enhancement and pattern disruption. Let us go through the various advantages of companion planting.

Pest Control
Marigold, garlic, leek, asparagus, coriander, etc. have pest-repelling property. Hence, they are planted with other crops. It is believed that marigold produce some chemicals, which can repel pests like aphids. It can also attract hoverflies, the predator of aphids. Likewise, garlic is planted with roses, as it is said that garlic can repel rose pests. In another method, pests are diverted from their target plants by planting some other plants, which can attract them. It is seen that nasturtium bordering cabbage plants disrupted the pests, especially cabbage root flies. Cabbage root flies prefer nasturtium to cabbage, as the larvae of this insect like to feed on the former than the latter. Another plant used for this purpose is clover. Another technique is to place decoys made of cardboard or some other material, which can divert the pests.

Pollination
Plants which produce nectar and pollen, can attract insects. These insects can be beneficial in two ways - pollination of crops and pest control. As adults, these insects undertake the pollination task and in the larval form, they feed on pests.

Nutrient Supply
It is seen that legumes like peas, beans, lupins, etc. can benefit the soil by releasing nitrogen stored in its roots. White clover is also planted in some gardens for the same reason. Another such beneficial plant is yarrow, which is considered to increase the strength and vigor of neighboring plants. This plant is a storehouse of phosphorous, silica and calcium and can be added to the compost. It can also attract beneficial insects like hoverflies and ladybirds.

Support and Shelter
Planting tall-growing plants with low-growing shade-loving plants is found to be beneficial for both. Tall plants can provide sufficient shade for the shrubs and also act as a windbreak. Even creepers can be planted in between, in order to prevent the loss of moisture content of the soil. Taller plants can support the vines of climbers, thereby avoiding the use of trellises.

Flavor Enhancement
Planting some herbs with other crops can enhance the flavor of the crops. For example, chamomile can improve the flavor of onions, cabbage and cucumbers. Planting chamomile in your garden or agricultural area is considered beneficial, as the former is like a tonic for other plants.

Pattern Disruption
Growing a single crop over a wide area increases the chances of higher levels of damages due to pest. In companion planting, the pests are disrupted by the companion plants, thereby controlling the damage to some extent.

There are many combinations of plants which are successfully tried as companion plants. You can also employ this system in your garden, and find out some mutually benefiting plants.