• Companion planting is the planting of vegetables, herbs and flowers near one another so that they can help each other in the garden. Inter-cropping has been used by various cultures, including the ancient Romans and Native Americans, to ensure the health and well-being of their vegetable crops. In more recent history, organic gardeners have found that companion planting allows them to avoid using chemicals in the garden.
  
  

Shelter and Space Management

• Taller plants are good companion plants for low-growing vines and shade loving crops because they provide protection from full sun exposure and from windy conditions. According to Cornell University, squash, peas, pumpkins and cucumbers grow well when sheltered by taller corn plants. Sunflowers, beans, tomatoes, broccoli and cabbage all provide filtered sun to celery, lettuce and spinach. Vining plants climb the stalks of corn and sunflowers, which reduces the space they take up in the garden and allows room for additional plants.
  
  

Attract Beneficial Insects

• Various herbs, flowers and vegetable crops attract beneficial insects to the garden. Ladybugs, parasitic wasps, hover flies and lacewings, are natural enemies of many insects that damage and destroy garden plants. Clemson University states that sunflowers and dill bring lacewings to the garden. Yarrow, dill and sweet alyssum attract ladybugs, while mint, flowering broccoli and flowering radish draws parasitic wasps to the garden. Hoover flies are attracted to cilantro, mustard and fennel. Dandelion attracts the lacewing, parasitic wasp and lady beetle.
  
  

Natural Insect Repellent

• Organic gardeners have found that a wide variety of plants naturally deter damaging insects from the garden. The roots of marigolds release a chemical that kills nematodes; the marigold also keeps whiteflies away from tomatoes. Nasturtiums keep aphids, pumpkin beetles, whiteflies and squash bugs away from crops. Mint deters cabbage moths, flea beetles and ants. Brigham Young University of Idaho states that basil repels tomato horn worms, aphids, whiteflies and mosquitoes. Garlic keeps red spider away from tomatoes and repels aphids from roses.
  
  

Natural Fertilizer

• Plants are helped by other plants when they add nutrients to the soil that assists in their health and growth. Comfrey keeps the soil around it rich with nutrients which promotes health and growth in avocado and other fruit trees. Beans, peas and clover fix nitrogen from the air and release it into the soil so it can be absorbed by crops, including corn and grains. Soil conditions are improved for the next crop once beans have grown in that soil.
  
  

Improve Flavor and Vigor

• The flavor and health of many plants is enhanced by having another beneficial companion plant close by. Basil and lemon balm both improve the flavor and growth of the tomato plant. Brigham Young University of Idaho states that borage increases the production of strawberries and helps enhance the growth and flavor of tomatoes. The growth and flavor of onions and cabbage is improved by chamomile. Plant lovage throughout the garden to heighten the taste of most vegetables. Rosemary improves the development of cabbage, beans and carrots.