Yeh I noticed them sneaking in through the drain holes also. I used cut up old nylons, slid up the pot a few inches to cover the drain holes. Keeps em out of that entrance.
I noticed this morning, there was no new flyers visibly present. ( I stir up the soil and rock the pots back and forth to agitate them) I relaced all the traps and hanging strips and there are virtually no specks on them. Some of the traps are spotless! I'm not even sure the specks I saw weren't dirt.
The soil is very light and airy on the top couple inches and it seemed to have no adverse effect on the plants.
I am only a couple days from moving new seedlings and clones from the nursery to the veg tent and if I see one of those bastards.....
I noticed these gnats will significantly damage juveniles, cuttings and seedlings the most. Anything with a small underdeveloped root system. The adults apear harmless, but the hidden little larvae eat the shit out of your roots. I will NEVER place seedlings or cuttings anywhere near those little bastards. You can have vegging 12" plants that just plow along in your tent with no visible damage next to some 3-4" little seedlings or cuttings and your babies will fight to live and seriously stunt their growth.
I used the tent to start a bunch of tomatoes, chilis, and a few other veggies and nearly all my little garden seedlings only made it a couple weeks after they left the dome and went in the tent.
The larger, vegging pot plants next to them continued to grow. (little did I know what was going on under the soil)
What pisses me off the most is, I run a clean environment. I sweep regularly, remove my deadfall, wipe and dissinfect. I run a clean ship, but these gnats came in the soil!
If the companies are using correct composting techniques, the temps in the compost should reach a high enough temerature to kill eggs and larvae.
If you make your own soil (which is what I did) you have to be carefull. I followed a recipe from a reputable grower and the soil has worked beautifully, except for the gnats. If I decide to make soil again, I will be extremely carefull in my selection of the compost I use.
I am going to be researching coco coir as a new medium.