Companion Planting 101
Companion planting is a phrase frequently used in gardening circles. You’re likely already familiar with the concept but not the practice. That’s why we’re diving into what companion planting is, how beneficial it can be, and how you can put it into practice for your garden.
What is companion planting?
At its core, companion planting is simply the grouping of plants that will benefit each other in some way. You will interplant vegetables, herbs, and fruits with this gardening practice. For example, rather than planting a bed or row containing just tomatoes, you’ll plant tomatoes, marigolds, and onions together.
One of the most common examples of companion planting is known as the “Three Sisters” bed. Carried over from ancient times, native tribes would plant corn, beans, and squash together. The corn provides a structure for the beans to climb on. The beans provide nitrogen to the soil that the other plants need. The sprawling squash creates a living mulch blocking sunlight, reducing soil temperatures, minimizing moisture loss, and dampening weed growth.
Why should I try companion planting?
Companion planting is one of the simplest ways to bring diversity and sustainability to a garden.
After all, a healthy ecosystem does not grow the way we tend to garden. In nature, plants don’t grow in straight lines isolated from other species. A happy garden needs diversity, and that diversity provides many benefits for both the soil and the gardener. In addition to supporting soil health and biodiversity, companion planting allows the plants to support one another in unique and varied ways.
What are the benefits of companion planting?
As we said above, companion planting provides a long list of positive effects for both your plants and soil. Some of the main benefits include attracting pollinators, deterring pests, providing nutrients, and saving space. Let’s take a closer look:
Attract more pollinators
Everyone knows plants need to be pollinated to bear fruit, but sometimes that requires a little extra help from the gardener. Planting certain flowers with your vegetables can help attract pollinators and ensure a bountiful harvest.
Deter garden pests
Garden pests like aphids and squash borers can decimate a garden in hours. You can use companion planting to protect the plant's pests love by positioning them next to plants they hate. Or, use companion planting to attract garden predators like ladybugs; those pretty little bugs will decimate an aphid population in no time.
Soil aeration and nutrients
A less widely known benefit of companion planting is the ability of plants with longer roots to aerate the soil. For example, carrots grow deep into the soil, whereas lettuce is shallow-rooted. In addition to helping aerate the soil, deep-rooted companions can help to pull up nutrients from farther down in the soil and make them more readily available for shallow-rooted companions.
Larger or taller plants can provide protection for smaller shade-loving plants. For example, nestling a few rows of lettuce beneath a towering tomato vine is an excellent way to provide needed shade and extend the season for cool-loving lettuce.
If you’re looking for a way to make the most of a compact garden, companion planting could be the answer. Take advantage of the extra soil space by sneaking in herbs beneath tomato plants or tucking radishes around your peppers. When you use that extra space to grow additional plants, you get the added benefit of fewer weeds.
Where to start
Companion planting is as simple as placing two plant varieties in a shared space. However, there are a few things you want to keep in mind before getting started. Some plants work beautifully together, while others can harm or stunt the growth of their neighbors. But before we get into which plants work well together, let's discuss some key points essential for companion planting.
Know your roots
The first step to companion planting is to know your roots or the expected rood depth of each plant. The key to successful intercropping is to place plants with deep root systems in with varieties that have shallower roots so that they are not competing for space or nutrients at the same level.
Know your families
The next step to companion planting is knowing your plants' family. For the most part, there are 13 vegetable families. Below is a basic breakdown.
Better known as the allium family. Onionlike vegetables with grassy foliage, bulb roots, and intense flavors characterize this family. Examples of the allium family include garlic, onions, leeks, shallots, scallions, and chives. Alliums favor sandy, loamy soils with plenty of organic matter, a neutral pH, good drainage, and full sun.
Better known as mustards or cruciferous vegetables. Each member of this family is derived from the mustard plant. Examples include cabbage, broccoli, cauliflower, Brussels sprouts, kohlrabi, turnips, radishes, cress, bok choy, arugula, nasturtiums or watercress, collards, kale, and mustard greens. Brassicas favor cool weather, and many improve in flavor after a light frost.
Also known as the goosefoot family because the leaves of the flowering plants bear a slight resemblance to a foot. Examples include beets, Swiss chard, lamb’s quarters, quinoa, and spinach. Like the mustard family, goosefoots tend to favor cool weather.
The Compositae are part of the larger group of angiosperms, or flowering plants. These include endive, escarole, cardoon, artichoke, sunflower, lettuce, dandelion, and marigold. These crops favor cooler weather but can also be grown with sufficient shade.
Also known as the gourd family, cucurbits include gourds, squashes, cantaloupe, cucumbers, pumpkins, and watermelons. Members of this family are warm-climate annuals that benefit from sunny locations and fertile soil.
The Gramineae are one of the largest families characterized by herbaceous, grasslike staple crops. Examples include wheat, rice, maize or corn, barley, oats, and millet.
Better known as the pea family. This family consists of shrubs, vines, and herbs that bear bean pods. Examples include peas, beans (runner, Lima, common, fava, mung, and adzuki), and peanuts. Legumes prefer sunny locations with pH levels.
This family contains plants in the Solanum genus, often referred to as nightshades. This family includes tomatoes, potatoes, eggplant, tomatillos, tobacco, goji berries, peppers, and cayenne. Plants in the nightshade family require full sun, well-drained soil, and plenty of organic matter.
Characterized by aromatic plants with hollow stems, this family includes celery, celeriac, dill, chervil, coriander, parsley, carrot, fennel, and parsnips. Because many of these plants' edible parts grow underground, a loose, deep, stone-free soil with constant moisture is best.
More commonly known as the morning glory family, Convolvulaceaes tend to be more showy garden plants. This family contains sweet potatoes, yams, and water spinach, aka Chinese watercress. Generally speaking, this family prefers warmer tropical climates or a greenhouse and requires full sun.
This family comprises herbaceous plants known for their aromatic qualities and uses as spices, essential oils, and medicinal remedies. Examples include mint, basil, rosemary, sage, savory, marjoram, oregano, thyme, lavender, and chia.
More commonly known as the buckwheat family, examples include buckwheat grain, rhubarb, and sorrel.
Better known as mallows, this family is characterized by their tell tail five-petaled flowers. Common garden examples include okra, cotton, and cacao.
Now that we have a basic understanding of roots, families, soil, and sun preferences, we’re ready to go over what grows well together and why.
It would be exhaustive to list every plant and every companion that can go with it. The blow infographic outlines some of the most common companions for easy reference, and individual plants can be easily googled if you need more information.
4 Tips To Get You Started
Use appropriate spacing
Be sure to use correct spacing when intercropping plants. Plants should never be placed closer than the smallest spacing requirement of the vegetables being planted.
Take advantage of plants’ differences
Combine low-growing plants with friends that grow taller and plants with deep root systems next to those with shallow roots. Pair fast growers with slow growers so they don’t compete for nutrients. Place pants that require pollination with those that attract pollinators and aromatic crops next to those that need pest protection. Combine plants with tall stalks next to climbers to reduce the need for trellising.
Work with plants from different families
In general, plants from different vegetable families are susceptible to different pests and diseases than those of other families. Companion planting dramatically reduces the potential for devastating pest loss.
Be mindful of transplant and seeding issues
It’s challenging to place transplanted starts into beds that have been direct seeded without disturbing seeds—place transplants in the bed first and direct seed around the seedlings.
Isn’t it great that our gardens can work even harder for us with just a little extra planning? You and your garden can reap the rewards by utilizing the companion planting method. Hopefully, these starting guidelines have inspired you to try companion planting this gardening season. If you try companion planting, we’d love to hear about pairings in the comments below. In the meantime, we wish you a happy gardening season, and as always, until next time,