Fungus gnats in indoor plants - recommendations?

[CarterBeatsTheDevil]

I have posted about this before but not for ages. I have a recurrent fungus gnat problem which doesn't seem to be affecting the plants but does make me a bit miserable.

Nematode application seems to be the way forward, but the sachet makes an enormous amount and I'm not sure how to divide it best between the pots - any ideas?

I've also just discovered nematode pearls - can they be used on indoor plants or are they just for outdoors after sowing?

Very happy to hear about any non-nematode means of control. So far I've tried: diatomaceous earth (sort of works but leaves unsightly white crust over the plant's soil), bottom watering (I don't like not knowing how much water I'm giving), neem oil (didn't seem to be effective but perhaps I was using it incorrectly). I've also seen crushed shells which I assume just destroy the larvae as they come to the surface like diatomaceous earth.

Have you tried removing the top inch or so of soil to remove the eggs?
Crushed shells or any type of grit stops access to the soil.
Yellow sticky traps.
Sprinkling cinnamon is supposed to help too.

A combination of the above + nematodes got rid of it for me. Replacing the soil has been the quickest/most effective - and feeds your plants.

Ooh, I hadn't tried the soil removal thing. I did consider repotting but I have repotted all of these in the summer (and it did seem to deal with them back then). I'll try nematodes and crushed shells!

I used the yellow sticky inserts. Big round ones you stick in the pot. One was so completely covered there was no more yellow left!

Really effective, along with watering less frequently.

I guess I could start by just letting them dry out - the cacti at least, now it's cooling down. I can't do that to the calathea, though, she'll die to spite me

Ground cinnamon.

Fungus gnats drive me crazy and during Covid that was the only home remedy I could get my hands on. It works so well I've never used anything else.

What do you do with it, just scatter it over the top? I like the smell of cinnamon much more than neem oil

Surely bottom watering makes it easier to see how much water you're giving?

Maybe 🤔

Top dress with horticultural grit, and add a drip or two of washing-up liquid to the watering can.

You could also try a new spray that's becoming available in garden centres now, it is called SB Invigorator. I know of people who use it for treating other pests, and they say it works.

Yes. Scatter it on the soil. It was nearly instantly effective for me.