Anyone try Hydrogen Peroxide for fungus gnats?

I have been battling these @!#*ing fungus gnats for months now.
I did the top dressing of sand and that definetly slowed them down, but I observed the little bastards entering the pots through the drain holes on the bottom.
I ran out of sand and recently added some plants to my flower room that weren't top dressed.
Less than a week later I noticed the little bastards flying around the surface of the new plants.

I applied the crumbled mosquito dunk/water solution 5 days ago. Since this is a bacteria, it doesn't effect the adults. I am going to dig a little around the first inch or two of my plants and seek out these larvae.
The dunks work by the larvae ingesting the bacteria.
My concern is this. Most bacteria require 4 things to succesfully grow and develop a colony. moisture, temerature, PH and a host or food source to grow and feed on.
These dunks are designed to suspend in standing water and dissolve slowly over time, thus releasing the bacteria into the host (the host being the standing water)
I am wondering if the bacteria in the dunk, can thrive and grow in an environment that dries out every couple days and is not constantly moist.

I am going to see if I find any larvae today. If I do, I am going to dilute 4/1 water and peroxide and water my plants with this.

I have read several articles in gardening and horticulture websites regarding the uase of peroxide to kill fungus gnats.
Apearantly it kills the larvae on contact, and the chemical reaction with the soil, causes it to foam and break down into oxygen and hydrogen.
There are gardeners on some sites who even water periodicaly using this solution as a nutritional supplement.

I will try and find some larvae today and I will apply this technique to one plant and post my results.
I understand that any damage to the plant caused by this may take several days to notice, so I will follow up a week from now and so-on.

Be careful with H2O2, if you use the concentrated stuff it can easily fry your plants.
I was reading about those who use the weaker drug store 3% stuff regularly in their res too, but not the 29% stuff I don't think, at least not at in the quantity of 1 tbsp/gallon.
My hydro shop guy said that much of the strong H2O2 would sterilize stuff and kill the plants. He said to use 2 ml/gallon tops, so I just dosed my 5g res with 8 ml (2nd time, 1st was 2 days ago). I was treating fungus gnats and think they're gone, but wound up with a touch (I hope) of root rot, which is why I got the 29% H2O2, to help clean up the roots.
The stink of Pythium (root rot) certainly got knocked down after the first round, hoping this will be the end of that sad story.

Use lots of sticky traps. I got some sticky tape like strips just hanging up and to start out I put a few strips on the tops of the soil.
I don't know if the ones I use are scented or something but I had a tent teeming with them one time and just one day with a hanging sticky trap knocked them down to barely seeing any flying around. The strip went black with how many stuck to it in just 24 hours.

You can also use pyrethrum as a knock down spray.
But what ever you do, use strips as well. Ones that hang and some cards to put on the soil surface.

h202 can be used to F with larvae and also other things like pythium- but it has to be used in the right concentration so as not to fry your roots etc. If you are trying to have any organic soil life then forget about it because it will annihilate both good and bad.
Oh and you don't have to buy a 3% bottle... you just use less per bucket of water if it's stronger. Just like alcohol right? Beer is weak so you drink more and whisky you don't drink straight out of the bottle. You need to find the right ratio- ideally if you want to use it then your local hydro store will have a bottle made up for horticultural reasons (my store has a h202 + colloidal silver bottle for spraying benches, plants and to go in res tanks etc. The plant and room cleaning dosages are on the bottle so it's easy to use).

Look into Neem oil if you are trying everything and it's not working. Neem oil doesn't kill the bugs instantly- it instead ruins their hormones so they don't mature properly, don't eat, don't mate- etc. It can be used regularly as a preventative to make it hard for bugs to take hold and also used once you have them to make them weaker- which can help other things you are using to kill them. It can be used as a foliar and as a soil drench.

I haven't seen any gnats since the last time I sprayed for adults using Schulz's Fungus Gnat spray.
The smell of Pythium is practically gone after 3 cycles of change the res and add 10 ml of 30% H2O2 every second day.
I just added 5 ml after changing the res last night, hopefully the end of pythium.
The plants, especially one, sustained damage, but have healthy new growth.
I believe what started the whole mess was improper drainage, which I've addressed, along with the increased aeration of the res., I also stopped feeding during the dark cycle.
This is my 3rd round using a drip system.
1st one was great, but included a fight with thrips.
2nd one I thought had thrips again, but turned out to be fungus gnats, and had a severely reduced yield.
This one will have a reduced yield as well, but not as bad as last time.
Not as good as next time though....

I apllied 3% h2o2 diluted 4-1. I applied it to all 6 plants in the veg tent a couple hours ago.
I grow in soil and it foams quite a bit when you pour it on. You can actually here it kinda sizzling and popping. I probably just sterilized my grow medium of even the benefical life, but I guess it will be a lot like growing with coco coir now.
AS LONG AS THOSE LITTLE FUCKERS ARE GONE, I can deal with it.
I also hung several strips vertically suspended between the pots, and all the foaming seems to have agitated the adults. I already see 20-30 of the little bastards on the strips.

That has always been the battle with these. The larvae are killed by ingesting the bacteria in the mosquito dunks, but the flyers lay more eggs and the cycle begins again over the next couple weeks.
I am going to continue applying the dunks on a reguar basis, to prevent any future larvae, from maturing.

I am confident, this will end eventually.

3% diluted 4:1 gives 0.75%, I don't think that is strong enough to nuke your medium.
The adult flies aren't hard to kill, but you have to break the cycle.
I saw one fly on a sticky trap a week ago and I sprayed with Shultz's Fungus Gnat spray, and had sprayed 5 days before that as well.
Right after that I started fighting pythium, and haven't seen any flies in the room or on the traps.

It always ends eventually.

Stinky Buds said:

3% diluted 4:1 gives 0.75%, I don't think that is strong enough to nuke your medium.
The adult flies aren't hard to kill, but you have to break the cycle.
I saw one fly on a sticky trap a week ago and I sprayed with Shultz's Fungus Gnat spray, and had sprayed 5 days before that as well.
Right after that I started fighting pythium, and haven't seen any flies in the room or on the traps.

It always ends eventually.

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Yeah, I think your right. I need to apply some arial or foiliar spray. I see the adults getting trapped on the strips, but they always lurk about, and seem to reapear. I have neem oil. Do you think I should give the plants a spray? I cleaned and disinfected the entire tent last week also. (I used a 50 ppm bleach/water)
I just want to eradicate them in all stages at once.
Maybe I'll just go get some gnat spray.
Thanks Sticky

I rock 34% and it definitely will mess em up but you not gonna get rid of them until every piece of dead foliage and food is cleaned up (i.e. can of pop, old coffee cup, old leaves, soil on the ground) I'm sure your grow probably isn't all messy but you never know I've seen some funny shit. once you got it all clean and swept up you can go at em.

make sure to heave a lid on all soil and powdered ferts.

Mighty wash is awesome for em it kills them on contact and its not bad for your plants from what I've seen in my room. i usually take a pump sprayer and loosen the nosel a bit so it has more volume coming out. make sure its still a shower just a little bit thicker of one. Spray your soil down substantially, really let it soak in. i even spray the dray holes really really really well cause as you've noticed they sneak in there. if you use saucers under you pots I've even found they hide between the saucer and the pot AND between the saucer and the floor. so its good to spray those down.

The Yellow folded paper sticky traps work by far the best. i found a neat little trick too. when its brand new sprinkle soil on it, just a little tiny bit all over it. i don't know if it looks like bugs or it they are going to get the soil or what but it will fill up in a day or so compared to a week or 2 without. i went through them like crazy. i still kinda am to i haven't sprayed in a few weeks and they seem to always come back.

My buddy told me if you work a compost pile in your yard at all your pretty much guaranteed to catch gnats if your not like scientist careful.
they definitely suck but at least you can still pull 99% quality harvest with them, unlike most pests.

gnatrol is working wonders for me. azaguard is also effective. The gnatrol cannot be used in conjunction with h202 the azaguard can. As someone else said LOTs of sticky traps. I like to put one in each pot during a heavy infestation.

also, never feed at night. It is unnecessary and will only contribute to the overly wet conditions that gnats love.

HGK420 said:

I rock 34% and it definitely will mess em up but you not gonna get rid of them until every piece of dead foliage and food is cleaned up (i.e. can of pop, old coffee cup, old leaves, soil on the ground) I'm sure your grow probably isn't all messy but you never know I've seen some funny shit. once you got it all clean and swept up you can go at em.

make sure to heave a lid on all soil and powdered ferts.

Mighty wash is awesome for em it kills them on contact and its not bad for your plants from what I've seen in my room. i usually take a pump sprayer and loosen the nosel a bit so it has more volume coming out. make sure its still a shower just a little bit thicker of one. Spray your soil down substantially, really let it soak in. i even spray the dray holes really really really well cause as you've noticed they sneak in there. if you use saucers under you pots I've even found they hide between the saucer and the pot AND between the saucer and the floor. so its good to spray those down.

The Yellow folded paper sticky traps work by far the best. i found a neat little trick too. when its brand new sprinkle soil on it, just a little tiny bit all over it. i don't know if it looks like bugs or it they are going to get the soil or what but it will fill up in a day or so compared to a week or 2 without. i went through them like crazy. i still kinda am to i haven't sprayed in a few weeks and they seem to always come back.

My buddy told me if you work a compost pile in your yard at all your pretty much guaranteed to catch gnats if your not like scientist careful.
they definitely suck but at least you can still pull 99% quality harvest with them, unlike most pests.

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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.

Ive heard of them coming in soil too. I bought a bag of Greenlight once but i didnt run it before i found out. I was worried i got them from that just being in my house for a day before i found out but who knows.

anyone had issues with sunshine advanced #4?

You should pour glue all over the surface of you soil.

You need an ovicide, a repellant, and a contact killer. I use Gnatrol to kill the larvae and eggs. I make a solution of cinnamon, neem, cayenne, garlic and dr. bronners peppermint soap and after a watering spray the surface of my coco and the bottom 1/3 of my plant. This combination Gnats DO NOT like at all. 5 days with a pest strip and another application of the spray and Gnatrol and no more gnats. If you decide to make this spray, just be careful. Wearing a mask and eye protection is a good move. Also it has a strong smell so dont apply it too late or hit any flowers. Best of luck.

burgertime2010 said:

You need an ovicide, a repellant, and a contact killer. I use Gnatrol to kill the larvae and eggs. I make a solution of cinnamon, neem, cayenne, garlic and dr. bronners peppermint soap and after a watering spray the surface of my coco and the bottom 1/3 of my plant. This combination Gnats DO NOT like at all. 5 days with a pest strip and another application of the spray and Gnatrol and no more gnats. If you decide to make this spray, just be careful. Wearing a mask and eye protection is a good move. Also it has a strong smell so dont apply it too late or hit any flowers. Best of luck.

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Cool. I have everything but the peppermint soap.

RockyMtnMan said:

Cool. I have everything but the peppermint soap.

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You can proceed without it. Just mix it all in hot water to suspend the Neem. Just don't saturate the soil beyond a thin layer....it is not meant for the root zone. I think you will be happy with this. Good luck.

Nah burger time don't let him get away without some Dr. bronners!! that shit is amazing for way more then plants.. hell u can brush your teeth with it if you wanna lol!

i recommend a full body scrub in the morning (ESPECIALLY sensitive areas!) This stuff will wake you up more then 25 cups of coffee lol


Quick H202 question. I'm about to harvest and the last time i watered i used a healthy spot of H202. now is this gonna be apparent in the buds? i don't really think its a danger but who knows any advice would be awesome!

I think it is relatively neutral....it reacts releasing oxygen which leaves h2o? I think that is more than likely its appeal. Can I ask why you used it? I did once use a "root zone conditioner" which does the same thing but just concentrated. How do you mean apparrent? like fluffy? Burned?

I used it to get rid of the stink! one of my big ole 18 gallon tote was getting funky. this boss hog I'm running is an insatiable feeder and i just don't have the heart to mix up a tough batch so i was resorting to H202 and over watering her. i run a top dress organic based polish hydroponic system! (my own invention!) not realy my own invention but the name is. i use advanced 4 peat moss medium and rainbow mix and a bunch awesome myco's and then i feed them up to 400 ppm of some organic based hydro nutes that are pretty clean but not totally. (the ones most people use and think they are growing organic)

Now the polish hydro part thats me. instead of pumps lol i do it with a watering can. this is most peoples definition of dirt growing but most people are wrong

And like harsh. harsh smoke is a no no. i didn't figure it would theirs no metals or anything in it.

unrelated but u are a hgk guy right?

Might i suggest ground cinnamon. Thin layer ontop and when you water put another layer on. my gnat population is gone.