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Cannabis Companion Plants for Optimal Growth

Elizabeth Johnson
Elizabeth Johnson
cannabis growing with the right companion plants

Companion plants are a natural way to protect your valuable cannabis crop from pests and certain diseases. These beneficial species attract predatory insects to the garden, which can quickly eliminate harmful pests.

Positioning them between your cannabis plants can also help prevent the spread of mold and other fungi that can damage your harvests. Many companion plants improve soil health by enhancing soil structure and fixing nitrogen from the atmosphere.

In addition to protecting your cannabis, companion plants boost the overall health of your garden by increasing biodiversity. They attract pollinators, aiding in the success of your vegetable patch as well. Moreover, they have their own benefits. At the end of the season, you can harvest companion plants for use in meals and herbal teas.

Explore some of the most popular and effective companion plants for cannabis below. For the best results, start seeds in rockwool to ensure strong, healthy plants.

Best Companion Plants for Cannabis Growing

In nature, companion plants can be whatever grows naturally, and many aromatic herbs can serve this purpose. However, some plants are more effective than others. If you’re looking for the best companion plants for cannabis growing, here are the top choices.

potential of your cannabis garden with effective companion plants

Cerastium tomentosum: An Ideal Cannabis Companion Plant

Cerastium tomentosum, commonly known as dusty miller, forms a dense, mat-like ground cover. This fast-growing plant spreads across the soil surface, serving as an excellent cover crop. It aids in retaining moisture and shields microbial life from harmful UV rays.

Planting Instructions

  • Timing: Sow seeds directly into or around your garden beds in early spring. Do not cover them with soil.
  • Location: Scatter seeds over a well-draining medium in an area that receives full sun. South-facing or west-facing positions are ideal for optimal growth.
  • Soil pH: While cannabis prefers a pH range between 6.0 and 7.0, Cerastium can tolerate a wider pH range.


Sunflowers are excellent companion plants for cannabis, offering both beauty and protection. These towering giants can reach up to 3 meters in height and feature bright yellow flower heads, which add visual appeal to any garden. Importantly, they help safeguard your cannabis plants by attracting aphids, whiteflies, slugs, and snails away from them.

To grow sunflowers, sow seeds directly into garden beds or pots. They thrive in moist but well-draining soil, full sun, and sheltered spots that protect them from harsh winds. Sunflowers release an allelopathic chemical into the soil, which can inhibit the growth of nearby plants, making them perfect for use as barriers and borders.

Marigold as a Cannabis Companion Plant

Marigold (Calendula officinalis) features stunning bright-orange flowers and aromatic leaves, making it an excellent companion plant for cannabis. These flowers attract aphids, diverting them away from your cannabis plants. Marigold is a fast-growing plant that can be grown as an annual or biennial, thriving until the first hard frost. It tolerates poor soil but prefers well-draining soil, such as chalky, loamy, or sandy types.

Planting Instructions:

  • When to Sow: Sow seeds directly into garden beds and pots in late spring.
  • Spacing: Thin seedlings to 20cm apart for smaller plants or 30cm for larger growth.
  • Light Requirements: Marigold prefers partial sun and fits well under a polyculture canopy.
  • Height: This plant reaches up to 50cm in height.

By incorporating marigold into your cannabis garden, you can naturally manage pests and enhance the beauty and biodiversity of your growing space.

power of companion planting for cannabis cultivation

Alfalfa as a Cannabis Companion Plant

Alfalfa is an easy-to-grow and soil-enhancing companion plant, ideal for your cannabis garden. As a legume, alfalfa collaborates with soil bacteria to fix nitrogen from the atmosphere, providing an essential nutrient for healthy plant growth. For optimal nitrogen fixation, inoculate seeds with nitrogen-fixing bacteria before planting.

This plant also improves water penetration in the soil, ensuring your cannabis plants stay hydrated and vigorous. Known scientifically as Medicago sativa, alfalfa’s deep roots enhance soil structure significantly.

Red Clover: The Ideal Cannabis Companion Plant

Red clover is a perennial, bushy plant that collaborates with nitrogen-fixing bacteria in the soil to draw in substantial amounts of nitrogen from the atmosphere, promoting strong, healthy, and large cannabis plants.

This plant produces striking red-pink pom-pom flowers, which attract pollinator species to your garden. For optimal growth, sow seeds in early spring in cooler climates and in autumn in warmer areas.


Chervil, a versatile culinary herb, doubles as a natural insect repellent in your cannabis garden. Its mild aniseed aroma draws aphids away from your marijuana plants, deterring them from causing harm.

To cultivate, sow chervil seeds directly into nutrient-rich soil as early as March. Expect germination within a week, with seedlings appearing shortly after.


Belonging to the celery family, dill not only adds visual appeal when planted alongside cannabis but also acts as a natural deterrent against certain caterpillars and spider mites throughout the growing cycle.

Avoid growing incompatible plants alongside your cannabis companions to ensure optimal growth. While companion planting offers numerous benefits, selecting unsuitable companions could adversely impact your cannabis plants.

Companion planting serves as a natural and highly efficient method to enhance soil quality and promote overall cannabis growth. By incorporating complementary plants, such as those adept at enriching soil, deterring pests, or retaining moisture, you can optimize the cultivation process.

Strains featured in this article:

Elizabeth Johnson

Elizabeth Johnson is an experienced cannabis grower based in Oregon, with a passion for sustainable farming practices that spans over 15 years. Born in the lush landscapes of the Pacific Northwest, Elizabeth has dedicated her career to mastering the art of cannabis cultivation. Her deep understanding of the plant's needs and her commitment to eco-friendly techniques have positioned her as a leader in the field. Elizabeth is particularly interested in the development of organic growing methods and has experimented extensively with permaculture techniques to enhance the quality and potency of her crops. On this platform, she shares her in-depth knowledge and personal insights into the world of cannabis, offering advice on everything from soil health to the latest in strain innovation. Join Elizabeth as she takes you through the rewarding process of cultivating cannabis with a focus on environmental stewardship. Whether you are a novice looking to start your first grow or an experienced cultivator seeking to refine your practices, Elizabeth's guidance will help you grow top-quality cannabis while caring for the earth. Dive into her posts to learn more about the sophisticated world of cannabis cultivation and become part of a community dedicated to excellence and sustainability.
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