One of the easiest gardening techniques to implement in your garden is companion planting. This no-cost, low-effort planting method gives back huge rewards in yield, pest control, and disease-resistance.
What is Companion Planting?
Companion planting is a method of gardening that pairs specific plants together for the benefit of all. Some plants attract helpful insects. Other plants act as natural repellents to pests and diseases. Planting particular vegetables together builds healthy plant communities in your garden. Some plants support each other, while others will compete for nutrients, resources, and space and shouldn’t be planted in close proximity. Knowing which vegetables and herbs provide which service is vital to a successful vegetable garden.
A large planting of one crop type quickly becomes a beacon for hungry pests. When you interplant herbs, vegetables, and flowers together, it is more difficult for these pests to find what they are looking for. The mixture of scents and colors confuses them, making it less likely for an infestation to happen.
The Benefits of Companion Planting
- Plant Health – Vegetables absorb nutrients from the ground, changing the overall make-up of the soil. This works in favor of some plants but may be detrimental for other plants. Understanding what a plant gives back to the earth and what it takes out of it will improve the overall success of a garden.
- Improved Soil – Peas and beans make nitrogen more available in the soil for other plants. Vegetables with long root systems lift nutrients to the topsoil, which helps plants with shallower roots.
- Shade Control – Plants that need sun protection do well planted next to larger varieties for natural shade regulation.
- Support – Low-growing and vining vegetables can use taller plants as natural supports. For example, peas can use corn stalks or sunflowers to support their tall vines.
- Weed Blocking – Interplanting low-growing, sprawling vegetable plants between tall plants reduces open areas where opportunistic weeds like to grow.
- Pest Control – Many herbs, with their strong scents, are unpleasant to insects and prevent them from coming to the garden.
- Disease Prevention – Many pests bring or cause diseases to infect your vegetable plants. Companion planting to prevent pests also improves the overall health and resilience of your vegetables.
Companion Planting for Pest Prevention
These garden companions prevent pests from attacking particular vegetables, which is an excellent all-natural way to reduce infestations. Companion planting for pest prevention reduces the need for insecticides and other chemicals that may end up in the vegetables you harvest.
- Basil, borage, and dill work well to protect tomato plants from the tomato hornworm. However, mature dill plants also stunt tomato growth, so be sure to remove them before they are full-grown.
- Marigolds repel nematodes, which demolish plant roots. Marigolds can be planted with any garden vegetable but are especially good around tomato plants, which often suffer horribly from nematode attacks.
- Marigolds also deter bean beetles, as does nasturtium, summer savory, and rosemary.
- Parsley, dill, parsnips, and carrots encourage beneficial insects like ladybugs, spiders, and praying mantises. These beneficial insects eat the pesty insects.
- Nasturtiums act as a beacon for aphids. Planting nasturtiums in the garden means the aphids will throng to them instead of attacking your vegetables.
- Squash plants also benefit from having nasturtium planted nearby. It deters squash bugs and beetles.
- Planting tansy around beans, carrots, cabbage, celery, asparagus, corn, peppers, potatoes, peas, tomatoes, and lettuce wards off cutworms.
- Cabbage flies seriously affect cauliflower growth but are thwarted by the rosemary, sage, and zinnias. Zinnias act as an invitation to ladybugs, and ladybugs eat the cabbage flies.
- Cabbage moths are a considerable problem for cabbage, cauliflower, broccoli, kale, radish, and turnip plants. However, planting sage among these vegetables repels the moths. Catnip, rosemary, and hyssop also discourage cabbage moths.
- Apple trees benefit from having lavender planted near them. Lavender repels codling moths, which severely inhibit apple tree growth.
- Planting mint around cabbage and other brassica vegetables deters cabbage moths and ants.
- Japanese beetles are deterred by marigold and white geranium plants.
- Oregano is an exceptional deterrent for a wide variety of pests.
- Chervil planted with brassicas, radishes, and lettuce will attract good parasitic wasps and repel slugs.
Companion Planting for Better Harvests
- Three Sisters is the most well-known companion planting strategy. Corn, pole beans, and squash are interplanted together for the benefit of all. The tall corn stalks act as a natural support trellis for the bean vines. Large squash leaves shade the ground, inhibiting weed growth and improving moisture retention. Pole beans gather nitrogen from the air and transmit it back to the soil, which benefits all Three Sisters. Also, planting them together maximizes space use while also producing abundant yields.
- Garlic planted near beets improves the growth and flavor of the beets.
- Chives grown near carrots enrich the growth and flavor of the carrots.
- Cucumbers benefit in flavor and growth when nasturtiums are planted nearby.
- Planting summer savory or chamomile near onion plants improves the flavor and growth of the onions.
- Mint enhances the flavor and health of pea and bean plants.
- Potato patches are better protected from pests when horseradish is planted near them.
Some vegetables don’t work together at all and should not be planted near each other. These plants are often called combatants.
- Onions, garlic, and beets will slow or stunt the growth of peas and beans.
- Sunflowers inhibit the growth of beans and potatoes.
- Cabbage and cauliflower compete for resources to the detriment of both.
- Fennel shouldn’t be planted in the vegetable garden. It inhibits the growth of tomatoes, beans, kohlrabi, and many other vegetables. Fennel attracts many beneficial insects, though, so it is great to have nearby the garden.
- Melons and potatoes are both heavy feeders. Don’t plant them near each other because they will compete for resources and nutrients.
Much of what is known about compatible and incompatible plants are a result of years of experience. Gardeners over the centuries have experimented and passed down this information for the benefit of future gardens. If you like, do some tests to see which vegetables grow best together in your garden. It may vary from this list, or you may discover something completely new. We always recommend recording planting maps, pest issues, harvests, and yields in a garden journal for easy reference. A lot depends on the pests in your area. Maybe cabbage moths never show up in your garden, so you don’t need to protect against them. Pay attention to how your garden is doing, and you’ll be an expert very quickly!