Fungus gnats and hydrogen peroxide

hello all,
Trying to find the correct dosage of hydrogen peroxide (3%) for a gallon of water.
I don't want to know in parts. I wanna know in terms of Millileters. I'm growing everything organically and of course the gnats love that.
Most of my fans are yellowing now. (They hit hard while I was away on vacation).
Is my yield going to suffer dramatically?
Potency?
They're on day 30 of flower. Great genetics and buds look lovely (growing gg4s)
These fungus gnats are killing my babies slowly!

Hey,
I'm having a similar concern! (Outdoor and organic as possible)
Gonna Google a few home brew solutions.
I used 3% food grade peroxide a few weeks ago just preventative, apparently gnats thrive in most media.
Got eccofective defender pesticide free spray, but again most gnats seem to be in/on soil ,
Will let ya know what I decide on and progress!

1part 3% h2o2 to 4 parts water.


When you get tired of fu¢king around with the little basturds. Consider Pyrethrin.

that would be greatly appreciated! I came back to a TON of yellowing leaves. They werent even in sight during veg. Of course, they wait til I'm starting to actually see some great buds. bastards!

I've read 3ml per liter. or up to 2.5 teaspoons per gallon with the 3%. But it's also recommended to start much lower and build up to that. However, I'm not sure if that's in line with the 1 part 3%h202 and 4 part water ratio...
It would seem there would need to be more h202 for that ratio to make sense...

SouthCross said:

1part 3% h2o2 to 4 parts water.


When you get tired of fu¢king around with the little basturds. Consider Pyrethrin.

Click to expand...

Got it, I'm still looking for exacts here not parts. If i had to take a stab at math ( i hate math) you're saying for one gallon of water, use .25 gallons of h202. That equates to roughly 946.3529 ml of h2h02... but that is drastically different than the other mixtures which have it as low as 3ml per liter.

Pyrethrin... I'll look into it. is it foliar ? I'm not trying to spray the ladies with anything at this stage?

Worth soaking the grow media or just topical application? I did both a cupla weeks back ?

All h2o2 does is kill one stage of the gnat fly. The fresh hatched larva. It doesn't do anything about the adults laying more eggs or the eggs.

You don't spray the plant with Pyrethrin. Application is the top of the soil. The source of the gnats. You kill the adults, there won't be gnats hanging around up top. Chilling out, waiting for you to finish using h2o2 so they can get back to it.

Check out, 'Southern Agriculture natural 1% Pyrethrin'. Research what exactly Pyrethrin is. Also the stuff added to it.

I really hate gnats...most homemade remedies are useless against these dick bugs.

1st off, fungus gnats will take swims in H2o2 solutions, it won't do a fucking thing.
The only damage a fungus gnat will do is to a young plant, and then the larvae will attack the stem and destroy it.
Your yellowing of the fans is a normal occurrence, no sweat at this stage of your grow.
I know they are an annoyance, but in reality, they actually do no real harm to a mature plant.
They will not cause your leaves to yellow

SouthCross said:

All h2o2 does is kill one stage of the gnat fly. The fresh hatched larva. It doesn't do anything about the adults laying more eggs or the eggs.

You don't spray the plant with Pyrethrin. Application is the top of the soil. The source of the gnats. You kill the adults, there won't be gnats hanging around up top. Chilling out, waiting for you to finish using h2o2 so they can get back to it.

Check out, 'Southern Agriculture natural 1% Pyrethrin'. Research what exactly Pyrethrin is. Also the stuff added to it.

I really hate gnats...most homemade remedies are useless against these dick bugs.

Click to expand...

Yeah I have the yellow traps of death set everywhere, unfortunately as you mentioned that only stops the adults after the damage has been dealt. I will certainly look into it. thank you southcross!

Jimdamick said:

1st off, fungus gnats will take swims in H2o2 solutions, it won't do a fucking thing.
The only damage a fungus gnat will do is to a young plant, and then the larvae will attack the stem and destroy it.
Your yellowing of the fans is a normal occurrence, no sweat at this stage of your grow.
I know they are an annoyance, but in reality, they actually do no real harm to a mature plant.
They will not cause your leaves to yellow

Click to expand...

SO wait... the yellowing of most of the fans on only my gg4s, not my other two OGS ( which look perfect everywhere) isn't from the fungus gnats? I mean, I understand the fade for sure... but that would usually happen towards week 8-9. these were barely past a month when i noticed.
I'm wondering if me going to light on the growilla bud amendment might have caused it. You're certain they can't do serious damage to mature plants?

jmoneygrows said:

Yeah I have the yellow traps of death set everywhere, unfortunately as you mentioned that only stops the adults after the damage has been dealt. I will certainly look into it. thank you southcross!

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Gnat eggs take about 5-7 days to hatch. Pyrethrin won't kill the eggs. So it takes two applications to make sure to kill the whole chain.

Reapply any time you see a single adult. It might have just flown in or its from a hatch. Same thing. Repeat about 6 days later. Pyrethrin breaks down fast. ~36 hours.

They don't stop.

SouthCross said:

All h2o2 does is kill one stage of the gnat fly. The fresh hatched larva. It doesn't do anything about the adults laying more eggs or the eggs.

You don't spray the plant with Pyrethrin. Application is the top of the soil. The source of the gnats. You kill the adults, there won't be gnats hanging around up top. Chilling out, waiting for you to finish using h2o2 so they can get back to it.

Check out, 'Southern Agriculture natural 1% Pyrethrin'. Research what exactly Pyrethrin is. Also the stuff added to it.

I really hate gnats...most homemade remedies are useless against these dick bugs.

Click to expand...

Yellow sticky traps are somewhat useful, but once you got those motherfuckers, it's impossible to get rid of them witout a total soil change.
Been there, done it.

to add to that, GG4's are monsters..no theyre goliaths... they drink gallons of water a day, and still thirst for more. I'm just crossing my fingers its a possible nutrient deficiency and not root rot caused by gnats. I never overwater either, as most waterings occur right at the last minute when the biggest stalks start to tilt downward.

jmoneygrows said:

SO wait... the yellowing of most of the fans on only my gg4s, not my other two OGS ( which look perfect everywhere) isn't from the fungus gnats? I mean, I understand the fade for sure... but that would usually happen towards week 8-9. these were barely past a month when i noticed.
I'm wondering if me going to light on the growilla bud amendment might have caused it. You're certain they can't do serious damage to mature plants?

Click to expand...

Absolutely sure, no way the gnats are the reason for your yellowing leaves.
Some of my plants start yellowing at week 5 of bloom, so by the end, around 50% of my leaves have yellowed.
But it is totally dependant on the strain. Some strains don't yellow, others look like they are dying before harvest.
All depends on the plant.

Jimdamick said:

Absolutely sure, no way the gnats are the reason for your yellowing leaves.
Some of my plants start yellowing at week 5 of bloom, so by the end, around 50% of my leaves have yellowed.
But it is totally dependant on the strain. Some strains don't yellow, others look like they are dying before harvest.
All depends on the plant.

Click to expand...

yeah, this is my first time growing GG4s, but this isnt "some" this is a lot of the fans. Must be a deficiency. with growilla amendments they say to stop using the veg 10 days before.. looking back i think that mightve been a mistake, they prob needed that extra dose of nitrogen. Oh well, live and learn. The buds look great, I just hope yield doesnt suffer greatly

jmoneygrows said:

yeah, this is my first time growing GG4s, but this isnt "some" this is a lot of the fans. Must be a deficiency. with growilla amendments they say to stop using the veg 10 days before.. looking back i think that mightve been a mistake, they prob needed that extra dose of nitrogen. Oh well, live and learn. The buds look great, I just hope yield doesnt suffer greatly

Click to expand...

Could you post a picture?

Jimdamick said:

Could you post a picture?

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I'm under HDS lights, its gonna be hard to detect the yellowing. I'll try and snap a pic tonight right after lights out to get a clearer visual for you all. the leaves are yellow, a lot of the bottom ones were necrotic and shriveled, falling off. I chalked it up to heat as i was out of town and of course a fucking heat wave hits socal, the grow room hit 100 for god knows how long.
I had my friend water the plants exactly every 3 days, which shouldve been just enough to keep the girls from dehydrating.
this is my 3rd grow now, and I just love how every grow comes with different problems totally worth it tho...

First fungus gnats are a sign of over watering. Cut back on watering.

Second, the easiest way to deal with them is to disrupt the breeding cycle. Add a layer of sand, perlite or mulch to the top of pots or holes. This keeps the mother gnat from laying eggs in the soil.

They lay eggs and the larva live in the top couple inches of soil. Let it dry and it will rid them.

Yellow sticky cards will catch the rest of them.

whitebb2727 said:

First fungus gnats are a sign of over watering. Cut back on watering.

Second, the easiest way to deal with them is to disrupt the breeding cycle. Add a layer of sand, perlite or mulch to the top of pots or holes. This keeps the mother gnat from laying eggs in the soil.

They lay eggs and the larva live in the top couple inches of soil. Let it dry and it will rid them.

Yellow sticky cards will catch the rest of them.

Click to expand...

It doesn't matter when or how much you water. It takes a week for the eggs to hatch. You have to water the plant before that. I run my crop medium dry. The adults just dig deeper...but by then the plants need water. About the time for larva to emerge....

These bugs are serious basturds.

SouthCross said:

It doesn't matter when or how much you water. It takes a week for the eggs to hatch. You have to water the plant before that. I run my crop medium dry. The adults just dig deeper...but by then the plants need water. About the time for larva to emerge....

These bugs are serious basturds.

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Ok. Its still a sign of over watering and the steps I provided will eliminate them.

You can also take a water bottle and cut the end you drink out of about 2-3 inches down. Flip it upside down like a funnel and stick it in the bottom part of the bottle.

Put some apple cider vinegar in the bottom for a good trap.

jmoneygrows said:

hello all,
Trying to find the correct dosage of hydrogen peroxide (3%) for a gallon of water.
I don't want to know in parts. I wanna know in terms of Millileters. I'm growing everything organically and of course the gnats love that.
Most of my fans are yellowing now. (They hit hard while I was away on vacation).
Is my yield going to suffer dramatically?
Potency?
They're on day 30 of flower. Great genetics and buds look lovely (growing gg4s)
These fungus gnats are killing my babies slowly!

Click to expand...

I found this
http://www.plantadvice.co.uk/garden-advice/articles/general/the-ultimate-guide-to-killing-fungus-gnats/125