Gnat problem, perlite top dressing

Hey all, I've been having a gnat problem, not too severe but still an issue. I'm growing in coconut coir so I water every day and the gnats seem to love it just as much as my plant. I tried sticky traps but they don't seem to work well enough.


My question is, if I dress the top of the coco with a layer of perlite will this help with my pest problem since they want wet soil? I hear a layer of sand works but would perlite work for this?

Try diatomaceous earth along with sticky traps; deadly for gnats.

Perlite is dusty AF.Dont do it.mosquito dunks when I pot up for flower works for me(you can also use them now)Yellow sticky traps help catch them as well as show you first sign of pests.
Hypoaspis miles are bad ass little beneficials that sometimes show up to help with fungus gnat larvae. I used the dunks my last grow,didnt have any gnats,but i had a TON of miles running around for a few days.They may have been snacking too.

Sticky traps will kill them all

Try gnatrol or mosquito bits, both have bti to kill the larvae. Standard fungus gnat arsenal is bti drench to kill the larvae, DE or gnatnix to stop the adults from getting into your medium to lay eggs, and the yellow sticky cards to kill some adults and help monitor the problem. Need to repeat bti treatment every 7-10 days.

How do you guys use mosquito dunks .I have problem with gnats whole grow..And whats is the best way to get rid if them in new soil before putting a seedling??

Nematodes are the only way to control fungus gnats ..it’s the larvae that do the damage.

I have mosquito dukns but dont know how to use them, I tried put them in water they won't dissolve..I bought new soil for new grow I think its contaminated too.

Yellow sticky traps work over time. You can expect to see them for weeks if not a month with them but it will eventually work. And put a whole shit load out, not just one or two.

I hang fly ribbon up near the plants, I also cut the fly ribbon up and tape it down flat to cardboard and lay them in the pots.

Just crumble them on top of your soil or mix them in prior to potting. Good air circulation will bust their hustle. I keep enough fans going to keep the plants moving,, especially near the base of the plants. It makes it very difficult for them to fly. I also use the sticky traps, one at the base of each plant. I think the larva must come in every bag of soil. It's very difficult to totally eliminate them.

cindysid said:

Just crumble them on top of your soil or mix them in prior to potting. Good air circulation will bust their hustle. I keep enough fans going to keep the plants moving,, especially near the base of the plants. It makes it very difficult for them to fly. I also use the sticky traps, one at the base of each plant. I think the larva must come in every bag of soil. It's very difficult to totally eliminate them.

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I agree 100% that the larvae comes in the soil. I struggled with fungus gnats for my first few grows then quit soil. Last bag of FFHF had adults fly out when I opened the bag. Switched to coco coir after that.

SF nematodes if you already have gnats. If you worry about gnats in coco, bottom feed. Don't let the top of the coco get wet and the gnats won't lay eggs. Works for me so far so good few years no gnats (I see them, but the larvae aren't eating my roots anymore)

With bottom feeding no need for nematodes. Bottom of pots entry point must be blocked off from gnats, I double up pots to achieve this.

DaFreak said:

Yellow sticky traps work over time. You can expect to see them for weeks if not a month with them but it will eventually work. And put a whole shit load out, not just one or two.

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I have zero gnats now. There called Growers Edge.


CikaBika said:

I have mosquito dukns but dont know how to use them, I tried put them in water they won't dissolve..I bought new soil for new grow I think its contaminated too.

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What cindysid said.

Sticky traps....and...

Cut up the mosquito dunks in a big bowl. You want big chunks, small, and dust. (New dunks....old ones might not be effective)

Cover the tops of your coco with a good layer of the dunk mix.

Every time you water some of the dunk bacteria will seep into the coco.

And you can drop a whole dunk in your nute water for a while.

Sticky traps only catch flying adults.
The dunk juice kills the non adults in the coco.

If top dress only...go too long without a refresh and they will be back.

Those corn bits can get moldy and nasty.

Gnats in every sack of Fox farms, no extra charge.

Fastest, foolproof way to get rid of gnats.

Micro-lift BMC just a few drops in your regular feed mix once or twice and done.

https://4hydroponics.com/microbe-lift-bmc-2-oz.html

This will last a long, long time..

I have yellow sticky papers A4 format, bought some kind of dolomite powder, even crumbled mosquito dunks into the water but fuckers still flying around.. But I will tray sprinkle dunks directly on soil!! Thank you a lot guys!!

If in the correct size pot for your set-up you'll see no yield difference from watering every day to every other day, first hand. If the plants are wilted feeding every other day then use a bigger pot. This however depends on your root/canopy temps and root establishment being optimal so that the top inch and outer edges of the pot dry enough to make the area uninhabitable to gnats, yet the inner core of the pot is still wet enough to support the plant with no wilt. You'll waste a little coco this way but it's a cheap and hassle free solution that requires one less product and gives you a lot more free time (the true upside -.^).

On the flip side if you use a pot that is too big for your root establishment (or low temps) the plants won't take up enough of the water volume between feeding's, the outer/top inch of coco will stay moist for too long and will then support gnats.

If you use monthly top dress or teas w/e you may see a slight foot hold in gnats but they won't last long with this method, a week tops.

Air pots are a blessing when you get this right, since they allow most of the outer edges to dry properly giving the gnats nowhere to hide. If you get it wrong though, it's a bit of a double sided sword, they then have full access.

It's a vague guess but say you were using a 5L pot and feeding every day, you'd probably have to step up to around an 8L pot to get away with every other day feeding. A 10L pot every day would require a 15L pot for every other day. Really just a loose guide, and temps etc also play a role in it, you have a good chance to get away doing it with current sized pots, it's something you'd have to play around with, but won't regret when you get it.

Use whatever methods before gnats show up.....and your stickies will look more like this at the end of a run.

I just harvested.

CikaBika said:

How do you guys use mosquito dunks .I have problem with gnats whole grow..And whats is the best way to get rid if them in new soil before putting a seedling??

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Gnatrol is a better way to get the BTI. New soil, the best way is to bake the soil in the oven but for larger grows this can become difficult unless you know someone with a large industrial oven like for powder coating.