the-ultimate-guide-to-companion-planting-vegetables (2024)

• Definition of Companion Planting
• Advantages of Companion Planting
• Umbelliferous Plants
• Friends in the Garden
• Enemies in the Garden

Definition of Companion Planting

Companion planting is a method of growing plants in a combination that will benefit both species. A companion plant may repel pests, attract beneficial insects, benefit the growth of another plant, or improve its partner’s flavor. Further, companion planting could decrease the need for pesticides, attract pollinators, improve the soil, and increase your harvest.

Advantages of Companion Planting

A favorite example of companion planting is the growth of the Three Sisters. This ancient method of growing beans, corn, and squash together was supposedly taught to the settlers by Native Americans. The corn provides a natural trellis to support the pole beans’ growth. Beans provide nitrogen in the soil for the corn and squash.. The squash shades the ground for the corn and beans, providing a natural mulch that suppresses weeds and helps hold the moisture in the ground.

Companion planting doesn’t always have to be so scientific. It can be as simple as adding flowers to your vegetable garden. Some gardeners are strict about not using space in their gardens for anything except fruits and vegetables, but this thinking is changing with the decrease in the bee population. Anything you can do to attract bees to your garden is good, and bees rely on flowers. While there are specific benefits to certain flowers, any flower will help to draw pollinators to your garden. If you have extra flowers, plant them randomly throughout your vegetable garden to attract the bees.

Umbelliferous Plants

Umbelliferous plants are extremely important for your garden as well. Umbels are flat or rounded flower heads that are composed of multiple smaller flowers. Some examples of umbelliferous plants are dill, fennel and cilantro. These flowers attract predatory beneficial insects who will eat the pests. Umbels are attractive to ladybugs, parasitoid wasps, hoverflies and lacewings. These predatory insects will keep down the population of pests including aphids and the small cabbage white moth caterpillars. This group of plants is often found in organic gardens as a means of controlling insect pests. If you have an organic garden and plant organic vegetable seeds, you will want to follow through with organic pest control as well.

As mentioned earlier, beans can fix nitrogen in the soil. In other words, the bean plant can take the nitrogen found in the air and convert it to a usable form in the soil. If you pull the bean plant from the soil after it is finished producing beans, you will see small white nodules on the roots. That is the nitrogen. All legumes, including beans and peas, which are frequently grown in the home garden, have this ability. So, if you plant beans with a companion plant, as in the case of the Three Sisters, the plant that needs the nitrogen (corn) will have an immediate source from the nitrogen producer (beans). Another method of achieving this goal is crop rotation. When the beans are finished producing for the season, don’t pull the plants from the soil. Instead cut them at ground level and throw only the part of the plant that grew above ground into the compost heap. Allow the roots, with their nitrogen nodules, to remain in the soil. Next season when planning your garden and rotating the various plants’ locations, place the nitrogen needy plants, such as broccoli, squash, or leafy greens, where the nitrogen-rich beans were last year. By thinking about companion planting when you rotate your crops each year, you will help to maintain the nutrient balance of your soil.

Friends in the garden

If you’re not sure where to start, here’s a guide of plants that work well together and help one another grow healthy and strong. You might notice that some of these combinations also make good plate friends, too!

1. Tomatoes and basil. Not only do these two go together in the kitchen, but they also pair well in the garden. Basil helps the tomato plant produce more tomatoes and repels flies, mosquitos, and tomato hornworms. When you start your tomato seeds indoors, be sure to start plenty of basil seed as well.
2. Peppers and basil. Much the same as tomatoes, the basil will repel unwanted pests such as aphids and spider mites, as well as mosquitos and flies. It is also believed that basil improves the flavor of the peppers.
3. Carrots and onions (and tomatoes). Onions repel the carrot fly. Parsnips are also attacked by the carrot fly, so plant onions near them too. Another companion for carrots are tomatoes. The tomato plant will provide some heat-protection from the summer sun and produce solanine, which is a natural insecticide for the pests that attack carrots. At the same time, the carrot will help aerate the soil and allow more water to be absorbed by the tomato. So when you are planting your vegetable seeds, be sure to sow carrot seeds next to your tomato and onion plants.
4. Marigolds and most vegetables. Marigolds should be planted throughout your garden because they repel so many pests. One important companion role is in and among your cauliflower, broccoli, and cabbage plants. The marigolds are very effective at repelling the small white cabbage moth, which lays its eggs on your cabbage family plants. When those eggs hatch and the caterpillars start eating, they can destroy an entire small plant in no time. Marigolds are also good at deterring nematodes in the soil.
5. Dill and cabbages. Plant dill near your Brassicas (cabbage family). The dill will attract the beneficial wasp that will attack the cabbage looper. Dill is also said to improve the flavor and growth of cabbage family plants.
6. Nasturtiums throughout the garden. Nasturtiums work by repelling aphids and beetles, such as the pesty bean beetle. It also is effective against the squash bug and potato bug, as well as white flies in the greenhouse.
7. Summer savory and beans. Summer savory also repels the bean beetle and is believed to improve the growth rate and flavor of its companion beans..
8. Garlic and vegetables. Garlic will deter the Japanese beetle and aphids in the garden, plus, a garlic oil spray is an effective way to deter rabbits and deer.
9. Borage and strawberries. Borage is a great plant to include in your garden to attract pollinators. They love the edible flowers, so it’s great to plant borage near strawberry beds.
10. Chives and fruits. Chives are good companions to apples, berries, roses, grapes, carrots, peas and tomatoes. Chives are also said to repel aphids and Japanese Beetles while improving the flavor and growth of their companion plants.

Have fun with companion planting. While some combinations are the result of scientific testing and knowledge, a lot has been passed down through gardening families and may or may not be valid. Still, don’t be afraid to experiment. Think of it this way, if you are going to plant chives anyhow, why not plant them next to the peas? If you are planting a number of tomatoes, do your own experiment and surround half with basil and the other half without basil.

Enemies in the garden

Remember that just as there are companion plants that should go together, there are some combinations that can be detrimental. For example, don’t put all the plants from the same family next to each other. If your broccoli is hit hard by the cabbage looper, they will quickly move to the cauliflower and cabbage plants right next door. If you place similar plants in different parts of the garden, you have a better chance to solve your infestation problem before the pests find the rest of your plants. The same is true of diseases. The family members of the infected plant will also be infected if they are planted adjacent to each other, while they may be safer in different parts of the garden.

Here are some plants that should not be planted together:

1. Green beans and onions. Keep green beans away from onions. It is believed that onions will stunt the growth of the green beans.
2. Cucumbers and herbs. Don’t plant cucumbers near your herb garden. It is believed that aromatic herbs such as sage can stunt the growth of the cucumbers.
3. Tomatoes and corn. Don’t plant tomatoes near your corn. Both are susceptible to corn earworm. Also, don’t plant your tomatoes near your potatoes. Both tomatoes and potatoes are susceptible to blight, which could be spread from one to the other. Blight can also infect squash.
4. Potatoes and cucumbers. Don’t plant your potatoes near the cucumbers. Cucumbers can encourage blight which will attack the potatoes.
5. Kohlrabi and tomatoes. Don’t plant kohlrabi near tomatoes because the kohlrabi is believed to stunt the growth of the tomato.
6. Radishes and chervil. Chervil will make your radishes hot. This can be considered a good or bad depending on your heat preference!
7. Turnips and mustard (and knotweed). Turnips should not be planted near mustard or knotweed. Both can inhibit the growth of the turnips.
8. Sunflowers and everything! Sunflowers send out a chemical from their roots that will inhibit the growth of other plants. Don’t plant any other plant closer than 12 inches from the sunflowers.
9. Celery and parsnips and potatoes. Celery can be grown successfully in many gardens, but it does not thrive near parsnips or potatoes.
10. Peppers, kohlrabi and fennel. Peppers will do well near just about any vegetable except kohlrabi and fennel. Fennel doesn’t get along with most other plants, but the kohlrabi is somewhat surprising because peppers do fine with other members of the cabbage family like cauliflower and broccoli.

This information about these so-called enemies in the garden come with the same caveat as the friends in the garden. There may be little or no scientific evidence to support some of these claims. If you have a large enough garden to accommodate the friends and enemies, you might as well use this information to your advantage. However, there may be other more important considerations to planning the most successful and productive garden.

Some things to consider first are access to sunlight. Don’t position large plants in a location that will shade other plants. Don’t plant two water seekers in the same bed where they will have to compete with each other for moisture. The same is true with heavy feeders. Don’t place them where they have to compete. If you are planting a vining crop and you can’t grow vertically, don’t place it next to a vegetable that could be smothered.

Gardeners should be ready to learn something new every season, as there is no shortage of gardening best practices. Experiment with these friends and enemies in the garden to see if all goes as expected or if you discover something new. Have fun!