How do I get rid of fungus gnats?Updated 2 hours ago

Fungus gnats are common in living soil, and they are manageable. Break their life cycle in three ways: let the top layer dry back a little, catch the adults with yellow sticky traps, and go after the larvae living in the soil.

1. Fix the moisture

• Gnats breed where the top layer stays constantly wet. Let the surface dry a bit more between waterings, but do not let the whole container dry out.
• Keep mulch loose. Do not pack it down. If it stays soaked, pull it back for a while so the surface can dry.
• Water no more than 5 to 10% of the soil volume at a time.
• Do not leave seedling trays or pots sitting in standing water.

2. Catch the adults

Yellow sticky traps catch adults and show you whether the numbers are going down.

3. Target the larvae

• Bti is a naturally occurring soil bacterium that targets gnat larvae, not adults. Search for Bti labeled for fungus gnats and follow the label. Our article Bti for Fungus Gnats explains how it works and how to use it.
• Beneficial soil mites (Stratiolaelaps scimitus) live in the soil and eat gnat larvae. See our beneficial insect packs.
• Rove beetles are another soil predator.
• Beneficial nematodes work down in the soil on the larval stage.

Adults can keep emerging for a few weeks after you start, so give it time. Once the cycle is broken, numbers drop quickly.

Prevention

Inspect and quarantine new plants and clones before bringing them into your space.

Not sure it is gnats? Send a clear close-up photo through the contact page or the chat button and we will help identify it. More on moisture: Watering Protocol.