@sunlover I used some larger yellow lids that I took off some food containers. I'd say they are about 3 or 4 inches across. I just put the solution in them and sat it on the shelf. Interesting that I also tried a blue one. They didn't even touch the blue one. The web said they are only attracted to the yellow.
It can be a yellow dish if that's what you have. I put several around on the shelves between plants and was surprised at how many were drowned in there each day. I understand it also attracts aphids. I used Murphys Oil soap (a drop) - but I think any good liquid soap would work.
I have one of those long sticky things hanging up in there, but am also going to get the yellow sticky strips which people say they lay flat between plants.
I bought peroxide at Costco and hauled all the plants out and I did the peroxide treatment - and it was after that when I repotted some of them. I didn't see any larvae (and didn't see any when I did the potato thing either) - but even after all that, I still have some buzzing around the plants. The population is dramatically reduced though. My understanding is the peroxide only kills the larvae so you need something for the ones still flying around.
Then I've been spraying with Ferti-Lome Quik Kill. That is working well too (but not 100%). Still got a few in there.
Mostly I think I have to quit watering so much - but I started buying the Lady Bug Vortex soil from my local nursery. It wasn't wet when I bought it like the Miracle Grow was. I think the Miracle Grow had the gnats in it as it was very wet when I bought it. Also started making sure I let plenty of fresh air in there daily.
