Ah, the first batch of bruschetta from the garden will soon be ready. Is there anything better than the taste of garden-fresh heirloom tomatoes topped with sweet, fragrant basil? Of course, tomatoes and basil taste delicious together--but did you know that they grow well together, too?
Companion planting--the art of combining different species of plants to benefit one another in the garden--is a long-practiced organic gardening technique. Have you heard of a “Three Sisters” garden? Historically, Native Americans grew food for a balanced diet in a single plot of land. By planting corn, beans, and squash together on a hill, they could maximize their harvest in minimal space. The plants also proved mutually beneficial: the tall corn supported the climbing beans; the beans added nitrogen into the soil, providing nutrients for the corn; and the low-growing squash vines served as a living mulch, preventing weeds and helping to retain moisture.
Why Companion Plant?
Today, companion planting serves many purposes in our organic gardens:
Companion Planting Benefits: Deter Pests.
Scent attracts many pests to their host plant—a plant where an insect lays eggs, knowing that the plant will serve as a food source for the newly hatched larva. By interplanting strongly scented herbs and flowers among crops in the our vegetable gardens, pests become confused, leaving our future dinners in peace.
It’s aggravating to grow a beautiful crop of cabbage, for instance, only to find it riddled with cabbageworm holes. We’ve all been there, right?
Examples of companion plantings that repel pests include:
Garlic or garlic chives with roses: repels Japanese beetles and aphids.
Basil with tomatoes: repels hornworms and mosquitoes.
Nasturtium with squash: repels squash bugs
Tomato with asparagus: repels asparagus beetle
Mint, thyme, and chamomile with brassicas: repels cabbage moth
Border of thyme or lavender: repels slugs in the garden
Onions with carrots: repels carrot fly
Radish with cucumbers: radish flowers serve as a trap crop for cucumber beetles
French marigolds may be one of the most used companion plants. Not only do they deter Mexican bean beetles, aphids, potato bugs, squash bugs, and nematodes (microscopic roundworms in the soil that damage many plants), they also add a beautiful burst of color to the garden. After all, an organic edible garden should be beautiful, too.
Companion Planting Benefits: Attract Beneficial Insects.
Not all insects are bad. Along with repelling pests in the garden, it’s also important to attract beneficial insects.
Beneficial insects serve many purposes. Bees, butterflies, and some beetles provide pollination, which increases harvests. Other beneficial insects feast on pests, making our work easier. For instance, when you find a tomato hornworm happily snacking on your beautiful heirloom tomatoes, have you noticed small, white “spikes” on its back? Those small spikes are actually killing the hornworm—organically. Parasitic wasps lay eggs on the hornworm, and as the eggs hatch, the larva feeds on the hornworm, eliminating our garden nemesis without an ounce of pesticide.
Nature is amazing, isn’t it?
As gardeners, we can minimize pests and eliminate pesticides by encouraging beneficial insects to visit. The trick is to know which insects are the good guys, and what plants to include in the garden to attract garden helpers.
Some beneficial insects include:
Ladybugs: both the larva and adults eat aphids, small caterpillars, and pest eggs.
Braconid wasps: a parasitic beneficial insect, it lays its eggs on host insects. When the larva hatches, it consumes the host insect, killing it.
Hover fly: larva eats mealybugs, small caterpillars, and aphids.
Lacewings: larva eats aphids, small caterpillars and caterpillar eggs, small beetles, and insect eggs.
Ground beetles: consume many pests, from asparagus beetles to squash vine borers.
How can we recruit an army of organic helpers to keep our gardens pest-free?
Adding flowering plants to food crops attracts beneficial insects that will keep the pest population low, while also encouraging pollinators to boost harvests. Plus, some of the recommended plants serve a dual purpose: attracting beneficial insects and providing flowers and food for us, too. A few recommended plants include:
• Yarrow • Dill • Fennel • Queen Anne’s Lace • Asters • Angelica • Butterfly weed • Tansy • Golden Marguerite • Feverfew • Lemon Balm* • Mint* • Cosmos • Sunflowers.
(*Plant mints and lemon balm, also a member of the mint family, in containers, as the plants can overtake a garden with their vigorous growth.)
Also, allowing parsley, carrots, and celery to overwinter in the garden produces blooms the following year, which are attractive to many beneficial insects.
Remember to include a succession of blooms so that beneficial insects visit your garden spring, summer, and fall—and winter in mild climates.
Companion Planting Benefits: Increase Harvest and Improve Flavors.
While we often think of companion planting primarily as a method of pest control, companion planting also improves harvest flavors—and even yields. For instance, in a limited space garden, combining tall, sun-loving crops, like tomatoes, with shorter plants that enjoy a bit of shade in the heat, like lettuce, allows maximum use of space in a 4’ x 4’ raised bed. Add trailing nasturtiums around the border of the bed, and now we have beautiful, edible flowers to add to our lettuce and tomato salads. Incorporate a trellis along the back edge of the raised bed for cucumber vines, and we’ve added another ingredient for our organic salad. The nasturtiums encourage pollinators to visit, increasing the yield of tomatoes and cucumbers, plus they serve as a trap crop for aphids, protecting the plants.
Add a few radish seeds near the lettuce. Not only do radishes and lettuce grow quickly, the lettuce protects the flavor of radishes in summer when they can turn bitter. Add a dill plant or two in the corner, and encourage braconid wasps to hunt tomato hornworms for their nursery. We’re protecting the tomatoes while also growing an ingredient to add to a homemade salad dressing.
Companion Planting for Containers.
It’s easy to create a container garden that’s not only pretty, but edible, too. For a cool season combination, consider planting kale as a “thriller”—the central, taller plant in the combination. Add aromatic herbs, like sage, to protect the kale from cabbage moths as your “filler”. Finally, plant pollinator-friendly violas along the edge of the container as the “spiller.” The violas will tumble over the edge of the container as they grow, attracting pollinators and adding aesthetic appeal, and the flowers add a lovely, edible ingredient to meals.
Companion Planting Benefits: Add Beauty to the Kitchen Garden.
While companion plants play a terrific role in pest prevention, pollination, and improved produce flavor, one of the best reasons to add companion plants is aesthetic.
By creating a vegetable garden that’s not only practical but also beautiful, we tend to spend more time in the garden, sipping a cocktail while enjoying the flowers, or gathering blooms for a bouquet. The more time we spend in the garden, the more likely we’ll spot problems early—and can take quick action to protect our organic produce from hungry beetles and caterpillars.
Plus, who doesn’t love a garden filled with beautiful blooms and butterflies? Companion planting may be practical, but it’s also soul pleasing.
While companion planting packs many benefits into a small space, it does require a bit of thought about the garden. What crops will you grow? What pests also enjoy the same food you do? Which plants can help you fight off the bad guys while attracting the good insects? The time spent planning companion plantings is worth it--adding beautiful, beneficial flowering plants into your garden plan is much tastier than eating a toxic dressing of pesticide on your produce, don’t you think?
Besides, creating an organic garden filled with blooms is a beautiful way to eat healthfully while saving money, too.