What is Companion Planting?
In terms of agriculture, diversity is always more beneficial than monoculture. Diversity occurs in nature, and different types of plants have different ways of growing, and different impacts on the surrounding environment. In the same way that some plants compete with each other, some can provide benefits for other species in the area. In fact, some complement each other quite well — putting them together is called companion planting. It simply means planting complementary species near each other, so they can reap the benefits. It promotes healthy and full growth and reduces the amount of work needed to maintain each crop. This is a technique often used by professional landscaping companies to ensure plentiful growth and a healthy landscape – check out Nature’s Friends for more information.
How Companion Plants Work
There are a variety of ways that plants can help each other grow, from nutrient production to natural trellising:
Pest protection: Alternating vegetables with flowers and herbs is a helpful strategy for deterring pests in general, as the scents and colors can be more confusing to pests than a large patch of crops. Some flowers can deter specific types of pests, or even attract beneficial insects to the garden. For example, marigold is known to deter beetles and nematodes. Likewise, vegetables that are targeted by the same bugs should be separated to avoid spreading pests and disease.
Shade regulation: Many plant species have specific shade requirements for proper growth. Crops of a specific shape and size can fulfill these requirements naturally. It’s important to conduct proper research on complementary species for this one, as plants will quickly die off if they do not receive the right amount of sunlight.
Soil fertility: All plants impact the nutrient content of the soil they live in, either directly or indirectly. Some crops saturate the soil with nutrients that others need. Nitrogen-fixing plants host a specific type of bacteria that produce nitrogen for surrounding organisms. Beans are a nitrogen-fixing plant — they provide the soil with nitrogen, which is a vital requirement for carrots. A proper companionship can reduce the need for expensive fertilizers and additives.
Above and below ground spacing: Diversity of shapes and root styles can allow you to grow a large number of crops in a small area. Plants can have vastly different root systems that grow to varying depths and may spread out laterally or stay mostly beneath the plant. Pairing different root systems together allows plants to grow close together without competing for space underground.
Weed control: Similarly to diverse root systems, different shapes and sizes in plants can reduce the open space where weeds can take hold. Alternating upright crops with sprawling plants like strawberries or potatoes can maximize ground cover and prevent weed growth.
Growth support: Tall, strong plants like corn can act as a natural trellis for crops like peas. This can save space and reduces the need for trellis installations in the garden.
Types of Companion Planting
Almost any type of plant can be used for companion planting; there are endless lists of compatible crops that can benefit each other, and combative plants to avoid coupling. The “three sisters” technique is also extremely beneficial; this utilizes the compatibility of three different species to maintain the perfect growing environment. The term most often refers to the combination of beans, corn, and squash, which was a typical growth pattern for Native Americans. The beans produce nutrients for the surrounding soil, the corn provides physical support for the beans to grow, and the squash is a strong foundation for the soil, holding in moisture and providing some protection from larger pests. Although this is the most common trio, three sisters can be used with any triplet of species with similar features. In terms of companion couplets, these are some of the most common plant pairings for a vegetable garden:
Vegetables and vegetables: Different vegetable species can benefit each other via nutrient production or size and root diversity.
- White garlic and onions repel a variety of common pests, and garlic has even been known to improve the flavor of some crop species.
- Spinach and Swiss chard grow well under the shade provided by corn.
- Alternating spinach and cauliflower 60 cm apart can improve the growing process of both crops.
- Some vegetables to avoid coupling are tomatoes, cabbage, beets, peas, and corn, as they can be damaged by the same pests.
- Cucumbers are benefited by a variety of vegetables such as beans, celery, lettuce, corn, peas, and radishes.
- Tomatoes can provide ample shade for heat-sensitive carrots, as well as produce a natural insecticide. Additionally, carrots aerate the soil, allowing water to reach tomato roots more easily.
Vegetables and herbs: Herbs can provide a variety of benefits for certain vegetables, usually due to their aromatic features.
- Thyme is beneficial to cabbage, broccoli, and cauliflower, as it can repel cabbageworm.
- Dill and basil are known to repel tomato hornworms, among other common pests.
- Sage, rosemary, and catnip can deter cabbage moths, which are harmful to cabbage, collard, Brussels sprouts, horseradish, kale, and a host of other vegetables.
- Basil wards off flies and mosquitoes and improves the yields of tomatoes. This is also beneficial for peppers.
- Alternating mint and lettuce can help repel slugs that will feed on the leaves of the lettuce.
Vegetables and flowers: Flowers often have an influence on the types of insects present in the area, so they can provide effective pest control for nearby crops. They not only provide a pop of color in your garden, but they are also quite useful and can reduce the need for pesticides.
- Zinnias attract ladybugs, which can act as pest control for cabbage flies and other small pests.
- Marigolds are helpful for almost any garden vegetable, as they deter nematodes, which consume the roots of most vegetable species.
- Tansy repels cutworm, a harmful pest for carrots, celery, corn, lettuce, peppers, potatoes, asparagus, tomatoes, and more.