Indoor plant care is a process of observation. Before changing products or routines, compare the plant’s current condition with its recent light, watering, root environment, temperature and pest history. This prevents one symptom from triggering several conflicting treatments.
Why they appear
Adult fungus gnats are small dark flies often seen near moist potting mix. Their larvae live in the upper moist layers and feed mainly on fungi and decaying material, though large populations can affect roots.
- Confirm they are gnats, not fruit flies or drain flies.
- Check which pots stay wet longest.
- Remove decaying leaves from the surface.
Drying and trapping
Allow the surface to dry as far as the plant safely tolerates and improve drainage. Yellow sticky cards near the soil help monitor and reduce adults, but they do not remove larvae.
- Water based on plant need.
- Empty standing water.
- Replace persistently decomposed mix.
Escalation
Persistent infestations may require a labelled biological or pesticide treatment. Follow local product labels and avoid unverified household mixtures that can injure roots or create indoor exposure.
- Treat all affected pots together.
- Continue monitoring after adults decline.
- Quarantine incoming plants.
A simple action plan
- Identify the plant by botanical name where possible.
- Record the symptom, soil condition, light and recent changes.
- Correct the most likely environmental cause first.
- Recheck new growth before making another major change.
Local water, climate, building design and product labels differ internationally. Follow local horticultural and safety guidance when using fertilizers, pesticides, electrical grow lights or humidifiers.