Getting rid of fruit flies on in-door pot with peas

Question

I have a rectangular pot with soil where I have attempted to grow peas.

For some reason (I'm not fully certain, probably over-watering) that pot became a breeding ground for fruit flies.

I have read the posts about getting rid of the flies in general (traps etc..) but this isn't enough - I need to get rid of the flies breeding in the pot.

What can be done, that would hopefully not harm the soil or the pea plants?

I have tried:

• Various traps around the pot. They attract and trap flies, but more breed

• Drying out the pot and not watering. Didn't seem to help much

• Covering soil with small aquarium gravel (as per advice of someone I know). I don't think that helped at all.

Answer 1

The problem you are having is not with fruit flies. Their eggs are laid in the skin of fruit like bananas. Your issue is with fungus gnats. They are weak fliers and can be removed with hydrogen peroxide and water drench or if you really want to be sure a dilute solution of bleach and water.

• a mixture of one part 3% hydrogen peroxide mixed with four parts water watered into the plant until water comes out the bottom or
• a tablespoon of bleach to one quart of water poured into the plant until water comes out the bottom. Wait a few minutes and rinse with tap water or
• powdered cinnamon ( I have not tried this one)

Answer 2

The idea of covering the soil with shingle or small gravel is to prevent adult fruit flies from laying their eggs in the soil in the pot, but if you've already got an infestation, it might not help much. Also called fungus gnats, these are quite difficult to shift if you can't leave your plant to dry out quite a bit without threatening the health of the plant. You can try changing the soil, but it is a risk - it involves removing as much soil as possible from the roots of the plant, followed by washing the pot thoroughly, then filling with fresh, new potting soil and repotting the roots. Otherwise, vinegar traps placed near the plant should help by attracting the gnats, see here https://homeguides.sfgate.com/use-vinegar-rid-fungus-gnats-house-plant-40394.html but you will need to couple this with allowing the plant to dry out somewhat between waterings, ensuring that the pot drains down freely through the holes in the base, and never leaving any water in an outer pot and tray after watering.