The concept of companion planting is based on the idea that some plants grow better when planted alongside specific other plants. It’s something that’s largely existed in the realm of gardening folklore, and there is not much scientifically-verified research on the topic. However, generations of gardeners and farmers have had success with companion planting, and it would be naive to disregard the lessons we can learn from their experience.
With that being said, how can growing compatible plants help produce a more bountiful garden?
Some crops grow well in concert with one another because their height or shape complement one another. Other companion plantings are designed with nutrient synergy in mind (the consumption habits of the plants are different enough that they won’t compete for the same resources). Additionally, some plants will help to defend their neighbors, warding off pests with their natural chemicals.
Here are my favorite combinations for the garden or farm.
Basils and everything
Perhaps the most universally lovable companion plants are the basils. Whether you choose culinary types like Italian Genovese and Thai basil, or fragrant tea types like holy basil and Blue Spice-- the scented and nectar-rich basil blooms are wildly attractive to beneficial insects. By planting these wily garden warriors into your mixed plantings you are creating an attractive oasis for the beneficial insects that will help to manage your garden pest population.
Planting for Pollination
Plants like watermelons, cucumbers, and zucchini will require the presence of pollinators in order to produce fruit, however sometimes, especially early in the season, we find these flying insects are in short supply. By planting crops like borage, echinacea, sunflowers, and marigolds amongst the veggies in our patch, we are laying out the welcome mat for pollinators to come and work our crops! These flowers can be considered companions to the insect pollinated vegetables and fruits.
Lettuce in the understory
Leafy lettuce greens are notoriously sensitive to heat and blistering sun, so situating the plants beneath the shade of a towering wall of corn, cucumbers, or pole beans will help to keep the plants cool and prevent bolting. Additionally, radish and lettuce are known to play well together.
Cucumbers and corn
Anyone who has grown corn knows that raccoons can be a serious pest, they will decimate a corn crop, typically under the guise of night, and waking up to devoured crops is heart wrenching. Thankfully raccoons typically find cucumber plants to be repulsive, so planting a ring of cucumbers around the corn patch has been known to ward off marauding raccoons. Please keep in mind, a desperate raccoon may blow right past your cukes to get to your corn, so it is best to combine this companion planting technique with other anti raccoon measures!
Brassicas Love Stinky Plants
Members of the cabbage family are notoriously susceptible to predation by caterpillars like the cabbage looper. Partnering these crops with aromatic crops like chamomile, calendula onions or marigolds will create an odoriferous environment that wards off cabbage loving bugs. I particularly love resina calendula — it is the go-to variety for herbalists and anyone looking for a more potent variety.
One famous plant alliance is between tomatoes and basil. Not only do they complement each other in the kitchen, they also make excellent companions in the garden — a partnership said to result in better-tasting tomatoes. Since flavor is largely subjective, you’ll have to test this theory for yourself.
Weeds you can Leave be
Typically gardeners harbor an impulse to pull all unwanted weeds from their gardens, and for many reasons, it is indeed wise to keep your beds weed-free. However, in some instances leaving a few weeds to compliment your intended plants can have beneficial consequences. For example, purslane is a common weed in North America, it is succulent and runs along the ground creating a mat of foliage… but did you know that this plant is not only edible but fairly useful as a ground cover in the garden! Leaving a mat of purslane to occupy the space beneath your taller plants like sunflower, amaranth, and corn will help to regulate soil temperature and moisture and to prevent erosion! Chickweed is a similarly low growing ground cover, that, if pulled before going to seed, makes a quick growing ground cover. If Bidens, aka spanish needles, is a common weed in your garden, leave one or two plants to attract beneficial insects for your more pest vulnerable veggies.
Radishes and Carrots
Carrots are a notoriously slow-growing crop. The small seeds are often sowed in thick bands and later thinned out to a few inches apart. This means your carrot row plods along slowly and requires extra effort for thinning. Alternating carrot and radish seeds in a row will eliminate your need to thin, and it will allow you to harvest from your carrot bed early. Be aware that carefully alternating between carrot and radish seeds in the same row can mean that the initial seeding will be more labor intensive and slow, however, the space and labor saved in the long run are well worth it! Choose a thin, quick-growing radish like french breakfast, or Du 18 Jours to interplant with your carrot seeds.
Bring on the bugs!
Some plants can help play matchmaker between beneficial bugs and plants that need them. Interplant bee-loving varieties like monarda, chives and gaillardia throughout your veggie patch, especially near fruit trees and other crops which benefit from bee pollination. Fennel and dill can be interplanted with your vegetables to attract ladybugs, whose larvae are known to eat aphids.
The practice of companion planting has been around for ages, and arguably the most famous companion planting trio is an old Native American planting tradition called the Three Sisters Garden. This is a trio of corn, beans and squash which is detailed in a legend of three sisters. Corn acts as a living trellis for the beans to grow up, and beans enrich the soil, making it more rich for other heavy-feeding crops like corn and squash to use. The large, frond-like leaves of squash make a quick ground cover, discouraging weeds and retaining soil moisture for the other crops to use. Squash foliage is also spiny, helping to keep predators away from the bean and corn plants.
Speaking to the science of companion planting, it is important to note that most research regarding companion planting has not been rigorously scientifically verified and is largely anecdotal. However, science has shown that there is a benefit to diversifying what we plant on the farm and in the garden to reduce pest pressure.
Whether you're growing a small garden or a large farm, companion planting can play a role in your design with benefits to plants. Organic and regenerative agriculture are systems of growing that aims to emulate the natural design and rhythm of nature, so companion planting is a natural fit for this style of growing, however even large commercial operations have been known to employ some basic companion planting techniques!