Do you follow the principles of companion planting in your garden? See our tips on what plants to plant next to each other—and which to plant far apart—including popular crops like tomatoes, basil, potatoes, beans, and more.
What is Companion Planting?
It takes more than good soil, sun, and nutrients to ensure success in a garden. Time-honored gardening wisdom says that certain plants, when grown together, improve each other’s health and yields. For instance, some plants attract beneficial insects that help to protect a companion, while other plants (particularly herbs) act as repellents. Additionally, plants that require a lot of the same nutrients as their neighbors may struggle to get enough for themselves, producing lackluster crops.
Which vegetables should you plant next to each other? Which shouldn’t you plant together? Let’s take a look at the benefits of companion planting, then a list of the best companion plants.
Benefits of Companion Planting
There are plenty of reasons to plant certain crops together. For example…
- Shade regulation: Large plants provide shade for smaller plants in need of sun protection.
- Natural supports: Tall plants like corn and sunflowers can support lower-growing, sprawling crops such as cucumbers and peas.
- Improved plant health: When one plant absorbs certain substances from the soil, it may change the soil biochemistry in favor of nearby plants.
- Healthy soil: Some crops, such as bean and peas, help to make nitrogen available. Similarly, plants with long taproots, like burdock, bring up nutrients from deep in the soil, enriching the topsoil to the benefit of shallow-rooted plants.
- Weed suppression: Planting sprawling crops like potatoes with upright plants minimizes open areas, where weeds typically take hold.
Companion Plants for Vegetables
Some plants, especially herbs, act as natural insect repellents. They confuse insects with strong odors that mask the scent of the intended host plants.
- Dill and basil planted among tomatoes can protect from tomato hornworms.
- Sage scattered about the cabbage patch reduces injury from cabbage moths.
- Marigolds are as good as gold when grown with just about any garden plant, repelling nematodes which attack vegetable roots, especially tomatoes.
- Some companions act as trap plants, luring insects to themselves. Nasturtiums, for example, are so favored by aphids that the devastating insects will flock to them instead of other plants.
- Carrots, dill, parsley, and parsnip attract beneficial insects—praying mantises, ladybugs, and spiders—that dine on insect pests.
- Much of companion planting is common sense: Lettuce, radishes, and other quick-growing plants sown between hills of melons or winter squash will mature and be harvested long before these vines need more leg room.
- Leafy greens like spinach and Swiss chard grow in the shadow of corn.
- Bush beans tolerate the dapple shade that corn casts and, since their roots occupy different levels in the soil, don’t compete for water and nutrients.
- Tansy discourages cutworm, which attacks asparagus, bean, cabbage, carrot, celery, corn, lettuce, pea, pepper, potato, and tomato plants.
- Catnip, hyssop, rosemary, and sage deter cabbage moth, which is detrimental to a host of edible crops, including broccoli, cabbage, cauliflower, kale, turnip, and radish.
- Mint wards off cabbage moth and ants.
- Thyme thwarts cabbageworm, which munches broccoli, Brussels sprouts, cabbage, cauliflower, collard, horseradish, kale, and kohlrabi.
- Lavender is known to deter codling moths, which wreak havoc on apple trees.
- Zinnias attract ladybugs, so when planted near cauliflower, which is susceptible to cabbage flies, the ladybugs are there to control the pest population.
Plants that are not compatible with each other are sometimes called combatants. Here are a few:
- White garlic and onions repel a plethora of pests and make excellent neighbors for most garden plants, but the growth of beans and peas is stunted in their presence.
- Potatoes and beans grow poorly in the company of sunflowers, and although cabbage and cauliflower are closely related, they don’t like each other at all.
One of the keys to successful companion planting is observation. Record your plant combinations and the results from year to year, and share this information with other gardening friends. Companionship is just as important for gardeners as it is for gardens.
More Companion Plantings
Even plants in the woodlands are companions:
- Blueberries, mountain laurel, azaleas, and other ericaceous (heath family) plants thrive in the acidic soils created by pines and oaks.
- Shade-loving plants seek the shelter provided by a wooded grove. The shade-lovers in return protect the forest floor from erosion with their thick tangle of shallow roots.
- Legumes and some trees, such as alders, have symbiotic relationships with bacteria in the soil that help them to capture nitrogen from the air and convert it to fertilizer, enriching the soil so plants can prosper in their presence.
Strange Plant Pairings
Sometimes plants may be helpful to one another only at a certain stage of their growth. The number and ratio of different plants growing together is often a factor in their compatibility, and sometimes plants make good companions for no apparent reason.
- You would assume that keeping a garden weed-free would be a good thing, but this is not always the case. Certain weeds pull nutrients from deep in the soil and bring them close to the surface. When the weeds die and decompose, nutrients become available in the surface soil and are more easily accessed by shallow-rooted plants.
- Perhaps one of the most intriguing examples of strange garden bedfellows is the relationship between the weed stinging nettle and several vegetable varieties. For reasons that are unclear, plants grown in the presence of stinging nettle display exceptional vigor and resist spoiling.
Want to learn more about companion planting? Watch our companion planting video about why vegetables need flower friends!