Gnat Flies...Damn Gnat Flies

Hello,

I'm new here, well, been lurking for some time acquiring info to get started on a medical grow. Since then I believe I've learned lots, and now that my license will be issued soon I have preparing steadfast.

That said, I intend to grow organically in soil which I have prepared in two batches. One if for the bottom half of the pot and the other for the top half. The bottom half amended for flowering. Approximately a month ago, I have prepared both soils as I've heard that the microbial organisms need to do their thing and make the nutes more accessible to the plants. Off the top of my head, the soil consists of:

Promix
Potting soil
Perlite
Worm castings
Bat guano
Bone Meal
Blood Meal
Azomite
Dolomitic Lime

So today I go to prepare some pots (yes I'm getting excited) and load the bottom half of the pots. I get to the container that has the soil for the top portion and the thing is CRAWLING WITH TONS of gnat flies. I'd been noticing them buzz around for some time and couldn't peg where they came from. I'd checked the other container twice (it was on top of the other) so I assumed that since that one was fine so was the other. But holy hell I was wrong.

So here be my dilemma. I'm quite upset that I've put this dedication into producing a microbial rich soil and fear having the back step the progress in my efforts to destroyed the little bastards. I live in a northern climate where the temp is still subzero. I'm not sure if putting the container outdoors to freeze will kill the gnats or only make them dormant. In either case, I'm pretty confident that the soil is riddled with eggs and freezing won't do diddly. My inclination would be to use a peroxide solution but fear killing all the microbial life I've put so much effort into attaining.

Any help or suggestions would be absolutely lovely and appreciated.

Cheers

get new soil, weather the old first.

a sticky trap dozen pack, some cooking/plant oil/soap/water mix, or even a torch...will kill all surface bugs. vacuum the bulk first? It would suck to bring these into your space though, and be over run with these bastards. they stick to buds, they eat delicate clone roots too.
good luck

mosquito dunks,
https://www.planetnatural.com/product/mosquito-dunks/

Pyrethrin.

chemphlegm said:

get new soil, weather the old first.

a sticky trap dozen pack, some cooking/plant oil/soap/water mix, or even a torch...will kill all surface bugs. vacuum the bulk first? It would suck to bring these into your space though, and be over run with these bastards. they stick to buds, they eat delicate clone roots too.
good luck

Click to expand...

Tell him about the real stuff.


Fuck Fungus gnats. I stopped playing with those little basturds a long time ago.

Excellent. Thanks for the fast responses folks. I've never heard of Pyrethrin and did a quick read about it. What I've read so far doesn't mention anything about killing the eggs. Would it be effective in that department?

3.5ml to one gallon water. It won't knock down house flys at that level. The smaller gnat files go to Hades as well as the larva. Apply to the top of layer of soil. Fluff with a fork. Mist again.

The brand I use is below. It's not organic. I use a Solo sprayer to apply. The cup on the end keeps over spray off the plant. Point it down and spray.

"Solo 418 One-Hand Pressure Sprayer, 1-Liter "


"Southern Ag Natural Pyrethrin Concentrate, 8oz "

Treat again after the eggs hatch. 4-6days. Then there's no more insect cycle. Fly tape to catch new adults entering the grow room.

Edit, added the window of the time it takes for gnat eggs to hatch.

I"m definitely thinking of going with the Pyrethrin and/or Nematodes. This is not some fly or two annoying me, these bastards have formed an army and must be subdued.

Thanks again for the heads up.

CannaBrained said:

I"m definitely thinking of going with the Pyrethrin and/or Nematodes. This is not some fly or two annoying me, these bastards have formed an army and must be subdued.

Thanks again for the heads up.

Click to expand...

Yes sir. Peace and good luck on your grow.

try this stuff first http://www.homedepot.com/p/Growstone-9-l-Gnat-Nix-Fungus-Gnat-Control-Top-Dressing-750GC33CF/300985886

I treat all of my soil with Gratrol (bti) twice. Its the same bacteria found in Mosquito dunks (an effective organic larvacide.). I try to stay away from pyrethrin but I know it works well for a lot of folks.
FFOF and RO are known to have fungus gnats but I think one (or both) have added hypoaspis miles predatory mites to combat the issue.
You can order the Gnatrol on Amazon or eBay in just about any size too. From 1oz and up. It works but you've got to treat more than once and use stickies to catch any adults.

Good luck with whatever you decide. Knock those little bastards out!

Oribated mites ate my fly problem, I found them by accident but they are a blessing of the woods

that sucks, nematodes work best against them. good luck.

Dunks and pyrithrins help. I don't spray the plants just the soil and I crumble the dunks and mix into soil and put some in my water also. I just top dressed with manure and castings that both brought them in last month The bacteria in the dunks eat the larvae and work but must be applie every two weeks. Amendments may look good when you use them only to open the bag later to be met with formation fo fighter gnats!

We make a good home for them also but they can be dealt with. 100% elimination may be impossible as they live in leaf mold etc. in the country and dumpster and trash with coffee grounds and other damp refuse.

Those plants I top dressed with contaminated amendments finished great with no ill effects.

Gnatrol

Gnatrol works very well and is probably the highest concentration of BTi and most expensive I believe but I found a product a few years ago called MicroBElift BMC (biologic mosquito control) which is very effective (10-11% BTi) and I believe the cheapest option.
Mosquito Dunks are okay 10-11% but stay away from the Mosquito Bits from the same company as they are only 2-3% BTi yet more expensive (RIP OFF).

Wiggle worm EWC are almost guaranteed to have gnat larvae from my experience, and need to be treated fresh out of the bag with BTi or else.

I got wiggle worm with millions of tiny little ants. And gnats in various compost including a local nursery-made premium compost, mushroom compost and Black Gold castings. I used my own compost until the skinks incident! Brought my own spider mites in the fall with house plants.

Here is a good reference for anyone new to these bastards. If you have fliers, it may be worth it to get a $20 shop vac. Give the plants a shake and vacuum above it.

I've used spinosad on a mild infestation. Only see one or two flying around now.

Spinosad works great and I think is organic , is it not? Correct me if I'm wrong.