Ants on Cannabis: Why They Show Up and What to Do
Ants on cannabis usually point to a sap-feeding pest such as aphids. Ants collect the sugary honeydew aphids excrete and, in return, guard them from natural enemies. Extension guides suggest keeping ants off the plant with sticky barriers or baiting them at the source, so predators can then bring the aphids under control.
Why Are There Ants on My Cannabis Plants?
Extension guides on aphids describe ants as a sign of honeydew. University of Arizona Extension says ants walking among aphids are probably collecting honeydew for food, and that some ants protect aphids and carry them from plant to plant (Arizona Extension). University of Nevada, Reno Extension notes that a line of ants climbing a plant is often the first clue to an aphid problem higher up (UNR Extension). These guides cover garden plants in general, not cannabis studies.
Do Ants Harm Cannabis Directly?
The sources describe the harm as coming mainly from the aphids that ants tend. Aphids suck sap from leaves, stems, flowers and sometimes roots (Arizona Extension). Honeydew can build up and support sooty mold (UNR Extension). Aphids that feed underground are covered in our guide to root aphids.
What ants do around aphids, and what growers do about it
Sources: University of Arizona Extension and University of Nevada, Reno Extension (garden plants in general).
| What happens | What growers do | Source |
|---|---|---|
| Ants collect honeydew from aphids for food | Check for aphids when ants appear | Arizona Extension, UNR Extension |
| Ants protect aphids from natural enemies | Control ants so predators can reach aphids | UNR Extension |
| Ants climb stems to reach colonies | Sticky barriers on trunks and branches of trees and shrubs, re-applied often in dusty areas | UNR Extension |
| Ant colony keeps sending workers | Baits that kill ants at their source | UNR Extension |
| Pesticides can kill natural enemies | Use fewer pesticides. Wash aphids off with water | UNR Extension |
How Are Ants and Aphids Connected?
Aphids excrete honeydew, a sticky liquid that holds sugars from the plant. Arizona Extension says some ants carry aphid eggs to their nest for winter and move them to a food plant in spring (Arizona Extension). UNR Extension says ants protect aphids from natural enemies to keep their honeydew supply, so the ants may need to be controlled before predators can reduce the aphids (UNR Extension). Beneficial insects do better once ants are gone.
How Do You Keep Ants Off Cannabis?
UNR Extension lists sticky barriers around the trunks and branches of trees and single-stemmed shrubs, and baits that kill ants at their source. It also suggests using fewer pesticides so natural enemies survive, and washing aphids off with a strong stream of water at regular intervals (UNR Extension). For more options, see our page on protecting plants from pests. If you use a bait, check the product label and local rules.
Sources
Some sources below studied hemp or other crops, or give general garden guidance, rather than studying drug-type cannabis. Their findings are reported as results for those crops or settings.
- University of Arizona Extension BYG1: Aphids
- University of Nevada, Reno Extension: Aphids and Their Management in Home Gardens
These ant and aphid notes stay general growing information, and Kind Seed Co took them from the extension guides above.
FAQ
Are ants in cannabis pots a problem?
Ants themselves are mostly a signal. Extension guides say ants on plants are usually collecting honeydew from aphids and may protect aphids from their natural enemies. Check stems, leaf undersides and roots for aphids. If ants are tending a colony, UNR Extension says control the ants so predators can reach the aphids.
Do ants mean my plant has aphids?
Often, yes. University of Arizona Extension says ants walking among aphids are probably collecting honeydew. UNR Extension notes that a line of ants climbing a plant is often the first sign of aphids higher up. Look closely at new growth and leaf undersides to confirm before you act.
What is honeydew on cannabis leaves?
Honeydew is a colorless, sticky liquid that aphids excrete as waste. University of Arizona Extension says it contains sugars from the plant, and a shiny, sticky film on leaves may be the first sign of aphids. Over time, excess honeydew can support sooty mold growth.
How do sticky barriers keep ants off plants?
UNR Extension says sticky barriers applied around the trunks and branches of trees and single-stemmed shrubs stop ants from reaching the aphids they tend. In dusty areas the barrier loses its stickiness and must be re-applied often. Once ants are blocked, natural enemies such as parasitic wasps and lacewings can work on the aphids.
