Friends, partners, collaborators, cohabitors . . .
Grown together, plants can be more than the sum of their parts
By Joshua Burman Thayer | Illustrations by Cheryl Angelina Koehler
Did you know that plants form alliances? Like humans, plants do better when they associate with other plants for mutual benefit, such as to procreate, grow strong, and ward off threats. Understanding the nature of these alliances can help gardeners plant for maximum productivity.
Many herbs and ornamentals attract essential pollinators to the garden with their precocious blossoms. Nasturtium, marigold, borage, bee balm, and comfrey are good examples.
Others ward off pests (including rodents) with the strong, sometimes even stinky chemicals they produce. Pungent plants like onion (Allium spp), marigold, yarrow (Achillea millefolium), and artemisia (Artemisia spp) planted along the edges of your garden will create a natural perimeter of defense.
Many plants have evolved to tolerate or even benefit from each other’s physical and chemical footprint in the rhizosphere (root zone). Some plants draw essential nutrients down into the soil. An example is the way legumes (peas and beans) help other plants by fixing nitrogen into the soil. Beets are chock-full of magnesium, which can help nearby members of the cabbage family achieve strong growth.
Due to their individuated growth habits, plants can utilize different layers of the growing space both above and below ground. Some plants help others by shading the soil, as when low-growing squash vines are used to shade and cool the roots of corn stalks towering over them in a traditional Native American “three sisters” arrangement. This is a “guild,” a group of plants that grow well together without competing for resources like sunshine and nutrients and work together like one big organism.
The three sisters are corn, beans, and squash. I like to do a deluxe “seven sisters” version adding peas, sunflower, Jerusalem artichokes, and cucumber. (For a four sister option read Josh's article May in the Garden: The Three Sisters of Summer Adopt a Fourth.)
Plants also mature at different rates, so there’s great advantage in planting fast-growing crops (called “catch crops”) in the gaps between larger, slower-growing items. You’ll be harvesting your catch crops before the main crops are at their full size.
Try sowing these catch crops directly into the ground in February or March for harvest in May and June: beets, peas, radish, arugula, herbs, lettuce, fava.
Maximize Your Tomato Zone
Everyone loves growing tomatoes, but the plants take a long time to mature and produce. As you invest time and space in planting your tomato zone, consider arranging it as a guild to promote maximum productivity. Your tomato zone guild should include tomato, peppers, and basil. For support, plant marigold, nasturtium, and yarrow.
By designing for beneficial interactions such as these, you can achieve higher yields as you naturally enhance and protect your garden. The illustrations below show three examples of companions that you can plant in spring in order to use the advantages of summer daylight and heat to produce summer bounty for your table. ♦
Joshua provides lots of good advice on how to implement these and other garden plans in his monthly Gardener’s Notebook, a feature of Edible East Bay’s free e-newsletter. Sign up to receive it here and also read Joshua’s past articles, search "Gardeners Notebook".
Joshua Burman Thayer is a permaculture designer and educator. A regular contributor to Edible East Bay, he has also written for Mother Earth News and Edible Silicon Valley. Find Josh and his work at nativesungardens.com, and follow him on Twitter at @nativesungarden.