Companion Planting: Flowers, Vegetables, Herbs and Fruit are Better Together

This is part 2 of our Companion Planting series. Read part 1, Companion Planting Deters Insects, Mice, Rabbits, and Moles.

Companion planting is not a new idea or a trend. In fact, it’s been done for centuries, from kitchen gardens in ancient Persia to modern industrial farm fields. This technique of growing plants together to help one another is a form of polyculture, which simply means growing multiple crops in the same space, using the diversity of natural ecosystems to enhance growth, and avoiding large stands of single crops, known as monoculture.

Alternatively, planting sweet peas in your flower beds add a beautiful annual to your spring display which has the added benefit of producing edibles. Kale, especially the exotic looking varieties, with tall, sturdy, ruffled leaves could be mistaken for elephant ears in your landscape. Except you can eat the kale and it’s one of the finest foods on earth, nutritionally speaking. Dill has feathery and delicate foliage which looks at home among any tall flowering plant or grasses – and it reseeds liberally.

Companion planting is an ancient practice

For centuries, many cultures grew crops, flowers, and herbs together. A great example is the indigenous peoples across North America and Central America who used the “Three Sisters” method of planting Maize or Corn, Squash, and Pole Beans together in one patch. The squash enjoys the shade of the corn and cools the corn roots; the corn and corn stalks provide support for the climbing pole beans. That’s truly companion planting.

When I plant sweet corn in my garden, I also plant beans, cantaloupe, nasturtiums, marigolds, and cucumbers; pole beans are planted with cauliflower and nasturtium; three varieties of tomatoes are planted with peppers, garlic, onions, carrots, basil, and parsley (and nasturtiums and marigolds again). Potatoes are planted with nasturtiums. Companion planting can also maximize garden space, as when an early harvest plant like radish is planted between hills of melons, which are harvested late in the season.

My garden beds barely have a square inch of earth unplanted, and I have few if any, pest problems. Birds love the sunflower seeds and perch on top of the sunflowers to spy crawling insects in the garden. After a rain, the garden is covered with birds looking for a quick meal and I have little crop damage from my flying friends. Well, a little, but that’s the price I pay for these insect eating machines.

Tip: To attract pollinators and add color to your garden beds, consider planting flowers like calendula, cosmos, alyssum, coreopsis, echinacea, marigolds, violas, and zinnias at the edges.

Companion planting increases biodiversity

Scientifically speaking, companion planting is planting two or more plant species next to or near each other for some cultural benefit (such as pest control or higher yield). The concept embraces several strategies for increasing biodiversity in your garden.

Scientists routinely provide evidence that supports companion planting. While they may not refer to the results by this name, their work shows potential for any home gardener to capitalize on the nature of plants to influence each other’s growth. Some plants host beneficial insects, some release nutrients advantageous to another crop’s growth, and others provide a buffer against the elements.

Companion planting benefits:

• Trap cropping: Use one plant to “capture” insects that are harmful to another plant. (see this post)
• Nitrogen fixation: Plant legumes like beans, peas, and clover amid nitrogen-heavy feeders like corn or potatoes to restore nitrogen to the soil. Legumes derive their nitrogen from the air, not the soil.
• Weed suppression: Plants such as squash, with their large foliage, shade out weeds and cool the roots among tall plants like corn and sunflowers.
• Improves the soil in the root zone: Perhaps deciduous trees shade your lettuce and spinach late in the day. The trees also provide nutrients in the form of autumn leaves and carbon, which help the soil retain moisture. When clover is planted around broccoli, it keeps the soil moist and cool, enhancing broccoli’s growth.
• Insect control: Certain plants produce chemicals from their roots or aerial parts that repel pests. For instance, it is well-documented that the roots of marigolds repel pest nematodes.
• Spatial interactions: Tall-growing plants like sunflowers can shade low-growing, shade-tolerant spinach. When corn is planted with squash, it is believed that the prickly vines of squash dissuade raccoons from eating the corn.
• Reduces plant diseases: When peas and grains are planted together, Asochyta blight is significantly reduced. The grain crop modifies the canopy microclimate, making it less humid and reducing the raindrop splash effect, which spreads blight spores.
• Attracts beneficial insects: Companion plants can provide a desirable environment for beneficial insects, arthropods, and predatory species like ladybird beetles, lacewings, spiders, predatory wasps, and predatory mites, which help keep insect populations in check.

Companion Planting Chart