Fungus Gnats Indoors: Non-Chemical & Chemical Control

Getting Rid of Little Black Flies (Fungus Gnats)

Ray has gnats in indoor grow. Soil too wet.

Core Fix: Dry Out

• Drain pots fully; wait until soil feels very dry.
• Water by weight.
• Ray can list plants for specific watering schedules.

Soil Amendment (Long-Term)

• Repot with 1:1 soil:perlite + handful horticultural charcoal.
• Improves drainage, deters gnats.

Quick Knockdown

• Spray soil surface with rubbing alcohol—kills on contact.
• Yellow sticky traps for adults.
• Potato slices to lure larvae.
• Knock-Out Gnats (biological) or Gnat Not (parasite) for serious cases.

Prevention

Sterile, bark-free, well-draining mix. Dump drain trays at 2 hours. Overwatering is the root cause.