Help! Sand gnats in houseplants!

[Mrsbrownsbuoys]

I wasn't sure whether to post here or in gardening ...

I've got lots of new cuttings and established houseplants and noticed a week or so ago there are what I believe are called sand gnats flying around and crawling on the soil.

Has anyone successfully got rid of them? And how?

I've put a jam jar lid with honey to catch them next to the plants which has caught a few. I've stopped watering the plants because I read the gnats need moist soil to lay eggs, but now the cuttings are drooping a bit and I've had to tentatively water them.

Anything I can treat them with? Preferably not pesticide, but I'm reaching the point where I will if I have to.

TIA

We had an infestation last year and nothing worked. In the end I had to get rid of a couple of plants that were the main source.

Oh no! Sorry to hear that. I'll just have to try I guess. What did you try?

Try repotting plants in fresh compost and wash the roots under running water in case they have eggs laid in them. Once repotted water as little as possible, it’s the end of growing season anyway and they require very little over winter. I water mine by soaking the pots in a sink of water then letting them drain before putting back, you don’t want them sitting in water.

I get fungus gnat nematodes from Amazon - they sort it out generally by killing the eggs in the soil (at least for a while!). We also have yellow sticky flower things to catch the adults.

Have had these before. Some good advice already on here but have had success with the below:

Stick the really sticky yellow sticky traps to the edges of the pots so that the young flies stick straight to them when they emerge from the soil.

Let the pots dry out as much as possible/water from the bottom of the pot.

Purchase diatomaceous earth from Amazon and sprinkle this on top of the pots. Its micro pieces are sharp and kills the larvae.

If you can remove the plant from the pot, wash off all the roots and replace the soil and move the pot to a different area this will be very effective.

Good luck! (I work in agroecology)

@BebesChamber

Have had these before. Some good advice already on here but have had success with the below:

Stick the really sticky yellow sticky traps to the edges of the pots so that the young flies stick straight to them when they emerge from the soil.

Let the pots dry out as much as possible/water from the bottom of the pot.

Purchase diatomaceous earth from Amazon and sprinkle this on top of the pots. Its micro pieces are sharp and kills the larvae.

If you can remove the plant from the pot, wash off all the roots and replace the soil and move the pot to a different area this will be very effective.

Good luck! (I work in agroecology)

This.

Hard to eradicate completely , but will defo slow the buggers down!

Thanks all! Great tips.

I spent yesterday afternoon repotting about half of them, I did wash the roots and also the pots, and put gravel on top of the soil. I'll look for some sticky fly paper. I used a jam jar lid with honey in and caught loads but it's difficult to put close enough to the smaller pots.