On Plant Communities and
Food Forests Permaculture concepts in action
By Joshua Burman Thayer
Plants, like people, thrive in community. As a landscape designer who works with permaculture strategies, I appreciate how nature evolves its plant communities so each member benefits from its associations with the others. That’s valuable knowledge to bring into
Permaculture—a term derived from “permanent” and “agriculture”—is a relative newcomer to landscape design. Conceived by horticulture academics David Holmgren and Bill Mollison in 1978, this design process links resources, use, and harvest into a connected whole. Permaculture asks us to consider the numerous harvests and functions we might realize simultaneously from one plot of land. The practice challenges us to shift our ideas away from a farm, orchard, or home garden as a mere place to produce food to an environment where plants, people, and creatures can thrive together.
Permaculture practitioners like to create dense, multilayered gardens or “food forests,” looking toward healthy natural forest environments for clues on how to establish and maintain a healthy plant community. A food forest is surprisingly easy to create at home, but first, let’s visit a hypothetical organic apple orchard to look at how the permaculture approach of “stacking functions” could increase the overall health and productivity of the growing area as we turn it into a
Here, the trees are planted in straight lines with nothing but weeds growing between the rows. In a conventional orchard, those weeds would be hit with Roundup (a probable carcinogen). Fortunately, that won’t happen here. Instead, we’ll plant the gaps between rows with secondary crops that can tolerate the shade of the trees, perhaps Asian greens and peas (good nitrogen fixers), daikon radish (breaks up and aerates soil),
Looking around, we identify rocky or otherwise marginal fringe areas where a third crop—flowers—could grow. Mexican marigold (Tagetes lucida) is a good choice because it deters both pests and weeds. Add in native flowering plants—like the nitrogen-fixing California redbud (Cercis occidentalis), yarrow (Achillea millefolium), California fuchsia (Epilobium californica), and Margarita BOP (Penstemon heterophyllus)—and we have created a pretty spot where the plants both enrich the soil and attract a biodiverse population of beneficial insects. The bugs assist in pollinating the fruit trees as they flower, thus increasing fruit productivity.
A food forest of your own
Do you have fruit trees growing in your yard? Citrus, apples, pears, or olives, perhaps? These can become the upper story of your home food forest. Lower layers should include nitrogen-fixing plants, pollinator attractors, root crops (which break up and aerate soil), and cover crops. You will want to add swales and mulch for reasons I’ll get to later.
Plants need nitrogen for healthy growth. Whereas many plants take nitrogen from the soil, others (known as nitrogen-fixing plants) take it from the air and pump it into the soil. Planting nitrogen-fixing plants like native redbud or lupine (Lupinus albifrons) or exotic edibles like carob (Ceratonia siliqua) or tamarind (Tamarindus indica) next to your production trees is a good strategy. All legumes are nitrogen fixers.
Whether you want to grow tomatoes or almonds, the crop’s flowers must be pollinated before the plants can produce their edible bounty. Creating nearby habitat for beneficial insects will attract pollinators. I like to think of these insectaries as farmworker apartment complexes: The shorter the commute to work, the more efficiently the insect helpers can practice their Integrated Pest Management services. Pollinator plants like Mexican marigold as well as natives like California fuchsia and yarrow will serve dual duty in repelling unwanted pest insects.
Organic farmers spend heavily to develop the health of their soils, all the while repeating the adage, “Grow the soil and the soil will grow the plants.” An important part of growing the soil is planting cover crops, and diversifying the plants in those cover crops will help create a more resilient system. Underneath my production trees, I like to broadcast a winter cover crop of fava, sweet pea, and clover in November or December. My summer cover crop, seeded in April or May, might include clover, vetch, and cowpeas.
Swales and mulch
In addition to planting the layers of your food forest, adding shape and texture on the ground level has many benefits. All successful organic farmers add mulch to grow their soils. A layer of straw or wood chips piled three to four inches deep on the ground will reduce weeds and retain moisture as it slowly decays to become a nutrient source for the plants and soil. Swales, a way to capture rainwater (and graywater), are mounds and depressions shaped into the ground. Excavated soil piled on the downhill side of the swale becomes a planting mound for your new fruit trees. Look for more on mulch and swales in a future article.
As we enjoy this season’s bounty, it’s a good time to look ahead and consider how the concepts of permaculture can repattern our minds as we discover new ways to live and interact with our environment. ♦
Joshua Burman Thayer is a permaculture designer and educator uniting ecology with aesthetics to create beautiful, productive natural systems that foster healthy ecosystems and bountiful community-scale production of organic food. He has written for Mother Earth News and Edible Silicon Valley. He writes a monthly “Gardener’s Notebook” for the Edible East Bay newsletter. Find Josh and his work at nativesungardens.com, and follow him on Twitter at @nativesungarden.