I am SO very much relieved. I have struggled with fungus gnats for a while, multiple grows. a grow ago they were so bad they were impacting my plants. I had sticky traps, fly traps, dissolved dunks and granulars in every watering to no help. I didn't add a layer of sand... That is where I was going next as much as I didn't want to do it.
Finished the grow, shut it all down. Gave it a some time before I emotionally recovered from the battle.
This time around I watched for a fresh delivery of FFOF soil and picked it up right away, hoping to reduce my changes of bringing them home. It worked. Mid grow I needed more soil... Stress... Tried the same. A few days later, I saw them, Just one or two. Sigh.
Well just before that I had accidentally overwatered a few plants, worse timing ever. So I lowered tent pole fan to be blowing on the soil. The gnats disappeared. the plants were back to normal moisture levels, fan went back to blowing mid to high. Gnats came back. It clicked in my mind, I lowered the fan. Gnats gone.. I typically keep some other plants around in there too, now i have some raddish, lettuce and mustards. I overwatered them for days, weeks.. I saw a few gnats, keep the fan on them and nothing.
So thats it huh? After all that fuss, money and frustrations I finally figured it out. The fix is too easy, For whatever reason, I never stumbled onto that information in all my reading.. BUT here I am gnat free and so glad to be over that shit.
this post for you might be like, well duh, this might help someone. whatever i have no gnats.