Fungus Gnats in Peace Lily: Natural Control

Identifying the Problem

Small white worms in the soil and tiny flies around your peace lily are fungus gnat larvae and adults. They thrive in constantly moist soil and feed on decaying roots and organic matter.

Why Rubbing Alcohol Isn't Ideal

Pouring alcohol into the soil can damage roots and beneficial microbes. Instead, use a targeted, plant-safe approach.

Effective Treatment Steps

1. Remove loose top soil: Discard the top ½–1 inch of soil (where larvae concentrate) without disturbing roots.
2. Apply insecticidal soap as a soil drench: Use a professionally formulated product (e.g., Safer Soap). Follow label directions. This kills larvae on contact.
3. Add a barrier: Top-dress with ¼ inch of sharp builder's sand or horticultural grit. The sharp edges deter adult egg-laying and damage larvae.
4. Adjust watering: Water only when the plant slightly wilts. Use the weight method: water thoroughly, then wait until the pot feels light.
5. Yellow sticky traps: Place near the plant to catch flying adults.

Prevention

• Let soil dry properly between waterings.
• Use well-draining mix (2:1 potting soil:perlite).
• Avoid saucers full of standing water.

For a full indoor pest guide, email the author.