Eliminating Fungus Gnats from New Houseplants: Systemic Soil Treatment and Repotting

IKEA Plants Bringing Fungus Gnats

The flies are emerging from larvae in the potting soil.

Protocol

1. Drench the soil with a systemic insecticide (e.g., imidacloprid) per label.
2. Wait 3 days for the chemical to translocate.
3. Repot each plant into fresh, sterile, well‑draining potting mix.
4. Discard the old soil.

This breaks the lifecycle. Monitor for any stragglers; a second drench is rarely needed.