Many gardeners believe that certain plant combinations create extraordinary conditions for helping each other grow. There have been many studies into whether this practice is scientific or not, but most gardeners do experimenting with their companion planting to decide on the best way to control pests and encourage growth.
How exactly does companion planting work, and what are some of the benefits?
- Companions help each other grow, i.e. tall plants providing shade for shorter plants that are sensitive to sun
- Using a small amount of gardening space more effectively. Vining plants that cover the ground can be planted below plants that grow vertically
- Using companion plants to either repel pests or lure pests away from what they are planted with
- Attracting beneficial insects that prey on destructive pests
Herbs in general are a good repellent to most pests due to their strong scents. They confuse pests by masking the odor of the companion they are planted with, making it harder for the pests to find the plant which they want to feed on. There are some herbs that should not be planted with certain vegetables, which will be included in the “bad friends” list later on in the post.
Marigolds are also a very versatile companion to plant with just about any other garden plant, as they repel beetles, nematodes and animal pests.
Nasturtiums are another versatile companion, as they are so appealing to aphids that the pests will flock to them instead of the plant they are a companion to.
We’ve put together a list of companionable combinations for your use! Keep in mind that companion planting is a very subjective practice, and you should experiment with combinations before deciding on what pairings are best for your garden.
- Roses & Chives – Gardeners have long been planting garlic with roses, as garlic repels most pests that feed on roses, so using garlic chives may be just as effective. They have small purple flowers in the spring that go along nicely with the roses as well.
- Tomatoes & Cabbage – Tomatoes repel diamondback moth larvae, which are caterpillars that chew large holes through cabbage leaves
- Cucumbers & Nasturtiums – Nasturtium’s vining stems wind throughout the cucumbers, repelling cucumber beetles as well as creating a nice habitat for predatory insects such as spiders and ground beetles
- Peppers & Pigweed or Ragweed – Pests called leafminers are attracted to the weeds and feed on them as opposed to the peppers. Just be careful to remove the weeds’ flowers before they set seed or the weeds can get out of control.
- Cabbage & Dill – The cabbage supports the weak-stemmed dill, and the dill attracts small wasps that feed on cabbage worms and other cabbage pests.
- Corn & Beans – The corn stalks offer a supportive structure for the beans to climb, and in return the beans attract beneficial insects that prey on corn pests, such as leafhoppers, fall armyworms and leaf beetles.
- Lettuce & Tall Flowers – Nicotiana and cleome give lettuce the light shade it requires to flourish in.
- Radishes & Spinach – The radishes draw leafminers off the spinach. The damage that the leafminers will do to the radish leaves will do no harm to the radishes growing beneath the soil.
- Potatoes & Sweet Alyssum – Sweet alyssum has tiny flowers that attract beneficial insects such as predatory wasps to protect the potatoes. You can also use the sweet alyssum to form a ground cover under arching plants like broccoli. Bonus, it will release a sweet fragrance to scent your garden all summer.
- Cauliflower & Dwarf Zinnias – The nectar from the dwarf zinnias will attract ladybugs and other predators to protect the cauliflower.
- Collards & Catnip – Planting catnip alongside collards can reduce flea beetle damage to the collards.
- Melons & Marigold – Certain marigold varieties control nematodes in the roots of melons just as effectively as a chemical treatment.
- Basil & Tomatoes or Lettuce – Basil improves the flavor of tomatoes and lettuce and also repels most pests including mosquitoes.
- Cucumbers & Sunflowers – The sunflowers provide shade as well as trellis for the cucumbers to climb.
There is a trio called “The Three Sisters” that has been around since before the early settlers arrived in America. The three sisters are a combination of corn, pole beans and either pumpkins or squash that are planted in short succession of one another. The corn is planted first, after the danger of frost has passed. When the corn is about five inches tall, the bean seeds are planted around the corn, and about a week later you’ll plant the squash seeds around the perimeter of your corn and beans. The corn offers support for the beans and the beans pull nitrogen from the air and bring it into the soil for the benefit of all three. As the beans grow through the squash vines and climb up the corn stalks toward the sunlight, they hold the entire structure together and contained. The large leaves of the squash shade the soil, keeping it cool and moist and preventing weed growth. The prickly squash leaves also keep away raccoons, who don’t like stepping on them.
Some plants hinder other plants’ growth and should not be planted next to each other. These partnerships can sometimes be referred to as “bad friends”. Below is a list of some plantings that are NOT suggested:
- Beans / Onions or Garlic
- Cabbage / Strawberries
- Carrots / Dill
- Corn / Tomatoes
- Cucumbers / Potatoes, Sage or other strong herbs
- Onions / Beans or Peas
- Peas / Onions, Garlic or Leeks
- Peppers / Kohlrabi
- Potatoes / Pumpkins, Squash or Tomatoes
- Radishes / Cabbage
- Squash / Potatoes
- Tomatoes / Cauliflower, Corn, Fennel or Potatoes
- Turnips / Potatoes
Companion planting is a very subjective practice. It is best to experiment with what you plant, keeping in mind the “bad friends” of course. In general, planting several smaller groups of one crop with companion herbs throughout your garden is better than planting one large crop of something. One large crop of a particular plant is more difficult to mask from pests, as they will be attracted by the strong scent.