Improve Your Garden with Plant Communities

Young pineapple.

Young pineapple.

Creating plant communities naturally increases yields, reduces pests, and protects the soil. It’s a sustainable, ecological method of gardening that imitates the diversity of natural ecosystems.

What are plant

communities?

A plant community is a diverse group of plants, or multiple crops, grown together. Also known as plant polycultures or guilds, they’re a stark contrast to the typical monoculture method of growing plants, especially edible crops, which uses mass plantings of a single type. They take their design cues from nature, where large numbers of a single plant is uncommon.

What are the benefits of plant communities?

Research has shown plant communities increase yields because water, soil nutrients, and light are more efficiently used. With a variety of plant roots occupying different sections of the soil, more of the nutrients and water is available in the same space than if only one type of plant is grown. It is an especially great way to garden in small spaces.

Insects become “pests” when there are too many of one kind. Monocultures encourage large populations of single insects, while plant communities encourage a diversity of insect life.  The insect population reflects the plant population. Mixed groups of plants create many niche habitats for various insects, including ladybugs, wasps, and hoverflies; predators of insects that can become pests, like aphids and caterpillars. With the biodiversity of insects found in mixed plant groups keeping the population of “pest” insects in balance, their numbers can’t grow unchecked. By allowing an insect ecosystem into our gardens, we avoid the use of harmful sprays, while reducing our need to provide the role of “pest” control.

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“As above, so below.”

Like the soil below the surface, plant communities completely occupy the space above it. Different plant forms and growth habits fill in the spaces, protecting the soil from the sun and wind. The shade that’s created retains moisture and keeps roots cool. This soil protection helps avoid erosion and topsoil loss. All of which adds up to happy soil life. The diversity of plant shapes creates “living mulch,” with the benefits of regular mulch, without the extra effort and expense.

How you can create plant communities.

A classic example of a plant community is the “three sisters,” a native American grouping of corn, beans, and pumpkin. The pumpkin grows on the ground, shading and protecting the soil, the corn provides a trellis for the beans and shade for the pumpkin, while the beans improve the nitrogen fertility of the soil. Using this example, we see how to grow plants on different vertical “layers” to maximise use of space. With this knowledge, we can create mutually beneficial plant groupings for our own individual needs and circumstances. To get you started, here are a few practical examples:

Ground layer: cabbage, melons or pineapple (on sunny side), lettuce, pumpkins and beets.

Second layer: Tomatoes, eggplant, broad/bush beans, and chard.

Third layer: Corn, climbing beans.

Fourth layer: Sunflowers, Jerusalem artichoke, dwarf fruit trees.

Feel free to create your own plant communities, on purpose, or by accident. When placing your plants, consider their orientation to the sun to maximise light. Arrange small plants in front facing the sun, (south in the Northern Hemisphere, north in the Southern Hemisphere) with plants gradually increasing in height behind. In tropical and subtropical areas, you will have to create more shade for lower layers, especially in summer.