Companion planting means designing your garden so that plants that are beneficial to one another are planted in close proximity. Plants work together to deter pests, accelerate growth, enhance the flavor of their fruit, and protect each other from the elements. Flowers and herbs provide assistance to vegetable plants, as can other vegetable plants. Mixing these three plant forms in your garden can also make it more visually interesting. In some cases, plants do not make good pairings because they share the same diseases or pests, which travel from one plant to the other.
Implementing a companion planting strategy allows you to have an overall more healthy garden, by employing an organic method of pest control. Certain plants attract beneficial insects that consume harmful garden pests. Nasturtiums draw aphids away from bean plants and sometimes from fruit trees. Planting heavily scented herbs, such as hyssop or lavender, attracts aphid-consuming insects. In general, aromatic herbs bring in beneficial insects to the garden. Sage and borage play an important role in attracting bees. Goldenrod encourages ladybugs to move in to your garden. Plants also deal with pests below the ground. Marigolds release compounds through their roots that drive away pests lurking in the soil. Chives, onions and garlic can also perform this useful service to their fellow plants.
Bean and pea plants pull nitrogen from the air and put it back into the soil when their growing season is completed and the vines wither and die. Leafy greens, such as spinach and kale, need this additional nitrogen their companion plants supply. Corn plants also benefit from being planted near beans and having an extra source of nitrogen. Beets are high in magnesium and contribute this important mineral to the soil.
Support and Protection
Tall plants, such as corn, provide a natural trellis in the garden for beans to cling to and climb. Cucumbers will grow up corn plants, too, and they do well in the same kind of soil. Tall plants also serve smaller ones by providing much-needed shade. Okra and lettuce make a good pairing because the okra provides enough shade to lengthen the growing season for lettuce as the weather warms up in the spring. Squash plants also like the partial shade provided by corn stalks. Sturdy plants like tomatoes and okra can also protect the fragile stems of young pepper plants from wind damage.
Faster Growth and Enhanced Flavor
One of the most remarkable benefits of companion planting is that it helps the garden produce tastier vegetables, and speed up the growth rate of certain plants. Garlic plays this vital role for beets when grown nearby. Borage contributes trace elements of important minerals to the soil to help its companion vegetable plants, such as tomatoes and squash. Gardeners have found that borage helps strawberry plants produce more flavorful fruit in larger quantities. Celery helps cabbage plants grow more rapidly.
Not all plants make good companions in the garden. Tomato plants may slow down the growth of carrots that are planted to close to them. Tomatoes and corn don't do well together because the same species of worm tends to attack both. Potatoes and tomatoes sometimes spread blight to one another.