Growing Marijuana in a Polyculture Environment

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Mimic natural plant communities to bring beneficial organisms into your marijuana patch. These four natural plant communities – grassland, oak woodland, chaparral, and coniferous forest – make up a polyculture, a self-sustaining ecosystem.
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Species diversity, exemplified here by artichoke, chives, calendula, kale, and dahlia, contributes one aspect of natural plant communities. Structural complexity, provided by trees such as Western red cedar, shrubs such as artichoke, and groundcovers such as herbs, creates habitat for beneficial organisms.
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Fennel flowers attract and feed many beneficial insects such as this adult parasitic wasp, which eats pollen and lays her eggs inside leaf-eating caterpillars.
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Many pollinators and other beneficial insects come to purple coneflower (Echinacea purpurea) to feed on nectar.
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The wild solitary native bee illustrates the diversity of beneficial partners attracted by herbs in the mint family, such as this oregano.
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Even in containers, you can create polycultures with species diversity and structural complexity.
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"What’s Wrong with My Marijuana Plant?" goes beyond this question and gets into specifics, providing solutions to the variety of questions marijuana gardeners have about their plants.

In What’s Wrong with My Marijuana Plant?: A Cannabis Grower’s Visual Guide to Easy Diagnosis and Organic Remedies (Ten Speed Press, 2017) authors David Deardorff and Kathryn Wadsworth guide cannabis growers through questions and concerns they may have about growing healthy plants. Readers can use the images, graphs, and diagnoses in this guide to understand their marijuana plants better. Here, Deardorff and Wadsworth encourage gardeners to grow a polyculture environment, comprised of companion plants, to create a stronger and more diverse plant community for marijuana to thrive within.

Marijuana is an annual weed. In a single growing season, a seed-grown plant can grow to 12 feet (4 meters) tall before flowering, setting seeds, and dying. It’s a tough plant that grows in many parts of the world as feral hemp, where no humans provide it with sprays, fertilizers, supplemental water, or extra light. The specially bred modern strains with maximum THC and/or CBD may be somewhat more finicky than their wild cousins, but even these new varieties are hardy plants.

That said, if your plants are beset with problems and failing to thrive, a poor growing environment could be to blame. By giving plants the best growing conditions, you minimize stress and maximize yield. It’s good for cannabis, good for your pocketbook, and good for the planet.

Plant Polycultures

Wild marijuana does so well on its own because of its inherent strength and its natural community. These communities are polycultures that feature high species diversity, structural complexity, and healthy, biologically active soil. These characteristics provide food, shelter, and reproductive sites for countless beneficial critters that help control pests and pathogens that may harm your plants. Mimicking healthy plant communities creates the best growing conditions and proves to be the best preventative measure and the most cost-effective way to keep plants healthy.

In a polyculture, lots of different kinds of plants grow adjacent to each other; in a monoculture, plants are all the same. In this case, that monoculture would consist of cannabis and nothing else, like a typical field of corn. By planting polycultures, you immediately create two important characteristics of natural plant communities: species diversity and complex structure. Choose plants from different families to establish species diversity. Choose plants that differ in height, width, rooting depth, flower color, and season of bloom to build complex structure.

Flowers and herbs are more than pretty faces and tasty treats. This diverse community, with varying structure, provides food and habitat for beneficial organisms. In addition, this community of plants lures useful predators, such as lady beetles, green lacewings, minute pirate bugs, and trichogramma wasps, to your crop. These predators seek out and destroy threatening pests. The habitat you create also offers a safe haven for beneficial fungi and bacteria, such as Trichoderma harzianum, Bacillus subtilis, and Pseudomonas fluorescens, that help protect your crop from pathogenic fungi and bacteria that cause diseases.

Best Companion Plants for a Polyculture

Several plants do the best job of attracting beneficial insects and creating a healthy polyculture environment. Choose those that work best in your climate and circumstances.

Asteraceae (sunflower family)

Achillea millefolium, yarrow
Aster species and hybrids, aster
Baccharis species, baccharis
Boltonia asteroides, boltonia
Coreopsis species, tickseed
Cosmos bipinnatus, cosmos
Echinacea purpurea, purple coneflower
Eupatorium perfoliatum, boneset
Gaillardia aristata, blanketflower
Helianthus annuus, sunflower
Leucanthemum × superbum, Shasta daisy
Ratibida pinnata, prairie coneflower
Rudbeckia species, black-eyed Susan
Solidago species, goldenrod
Symphyotrichum species, hardy aster
Tagetes species and hybrids, marigold
Zinnia elegans and hybrids, zinnia

Apiaceae (carrot family)

Ammi majus, laceflower or bishop’s weed
Anethum graveolens, dill
Angelica species, angelica
Coriandrum sativum, cilantro or coriander
Daucus carota, Queen Anne’s lace
Foeniculum species, fennel
Petroselinum crispum, parsley
Zizia aptera, heartleaf Alexanders
Zizia aurea, golden Alexanders

Lamiaceae (mint family)

Nepeta × faassenii, catmint
Ocimum basilicum, basil
Origanum species, oregano
Pycnanthemum species, mountain mint
Rosmarinus officinalis, rosemary
Salvia officinalis, culinary sage
Thymus species, thyme

Other plant families

Eriogonum species, native buckwheat
Lobularia maritima, sweet alyssum
Phacelia tanacetifolia, lacy phacelia
Spiraea alba, meadowsweet
Veronicastrum virginicum, Culver’s root

Create polycultures outdoors in the ground

To create polycultures outdoors in the ground, you can add one extra row of companion flowers and herbs per about five rows of marijuana and/or surround your patch with a border of beneficial flowers and herbs. Put beneficial flowers and herbs in the same row as your marijuana plants. In this case, select small, shallow-rooted plants (such as thyme, oregano, marigold, tickseed, Queen Anne’s lace, or cilantro) so that your marijuana does not have to compete for nutrients, sunlight, and water.

Create polycultures outdoors in containers

Do not plant flowers or herbs in the same pot as your marijuana. Cannabis is a heavy feeder and wants all the nutrients, sunlight, and water it can get. It will not be as productive if it has to compete with another plant for those resources in the restricted environment of a container. Instead, plant some extra pots with beneficial flowers and herbs, and place them next to your pots of marijuana plants. Shift pots around to find the best environment for each kind of plant.

Create polycultures indoors in containers

Indoors, you avoid many of the pests and pathogens that plague outdoor plots. However, even indoors your plants might be hosts to spider mites, aphids, scale, powdery mildew, gray mold, and other pests and diseases. Pests hitchhike into your grow room or greenhouse on your clothing or on your pets. They can also ride the breeze and float or fly through windows, vents, and doors. If you release any of the beneficial insects and mites covered in chapter eight to deal with these problems, put pots of flowers in the grow room or greenhouse to provide extra food and habitat for these beneficial creatures.

Reprinted from WHAT’S WRONG WITH MY MARIJUANA PLANT? Copyright (c) 2017 by David Deardorff and Kathryn Wadsworth. Published by Ten Speed Press, an imprint of Penguin Random House LLC.