Companion Plants Against Spider Mites: Protect Your Cannabis Naturally

Key takeaways

• Chives, basil and garlic make it harder for spider mites to settle near your cannabis.
• A garlic infusion sprayed weekly works as both a repellent and a light contact treatment.
• Marigold, already useful against Japanese beetles and whiteflies, adds to this protection.
• These plants reduce the risk of mites settling in — they do not replace treatment once an infestation is active.
• Plant them early in the season so they are established before the July–August risk peak.

In this guide

• Why do these plants repel spider mites?
• Which companion plants work against spider mites?
• How do you make a garlic repellent infusion?
• FAQ — Companion plants and spider mites

As with most cannabis pests, certain companion plants make the environment less inviting to spider mites before they ever settle in. They are no substitute for treatment once an infestation is active, but they meaningfully reduce the risk of one starting.

Why do these plants repel spider mites?

Spider mites, like many piercing-sucking pests, avoid areas dense with strong aromatic compounds. Chives, basil and garlic release sulphurous or intense scents that disrupt their settling, while cilantro and marigold add to the effect by drawing in beneficial insects that feed on mites.

Which companion plants work against spider mites?

Four plants stand out for how easily they grow in Quebec and for their documented effect on spider mites.

1. Chives (Allium schoenoprasum)

How it works: its sulphur compounds, close cousins of garlic's, limit mites settling nearby. How to use it: as a border, or lightly interplanted between cannabis plants. Bonus: edible and low-maintenance, it also repels certain aphids.

2. Garlic (Allium sativum)

How it works: its sulphur compounds (allicin) repel a broad range of pests, spider mites included — the same mechanism already put to work against the Japanese beetle. How to use it: interplanted, or as an infusion sprayed directly on the plants (recipe below). Practical upside: if you are already growing garlic against beetles, it protects against spider mites at the same time.

3. Basil (Ocimum basilicum)

How it works: the linalool it releases disrupts how spider mites orient and settle — the same mechanism that works against several other piercing-sucking pests. How to use it: interplanted close by, pinched back regularly to keep the foliage active.

4. Cilantro (Coriandrum sativum)

How it works: its pronounced scent makes the area less inviting, and its flowers attract beneficial insects that prey on mites. How to use it: as a border or interplanted, letting some plants flower to draw in those beneficials.

How do you make a garlic repellent infusion?

This homemade recipe works both as a preventive repellent and as a light contact treatment on populations already present.

• Bring 1 litre of water to a boil and add several blended garlic cloves.
• Let it steep for 12 to 24 hours.
• Strain the mixture, then dilute it with an equal volume of water in a sprayer.
• Spray affected or at-risk plants once a week.