Fungus Gnats - Strawberry Cough 31 days

[kbfl0912]

Hi all,

Well, I got some Feminized DP Strawberry Cough seeds. Out of 5, 4 germinated. I recently moved them into 1 gallon containers using an organic soil and perlite. They are 31 days now and are extremely small and the growth has been very slow. I thought I had a fungus gnat problem under control until yesterday....I walked into the room and the buckets that the plants are sitting on were covered in gnats. The top soil was crawling. Worst infestation I have ever seen. So, I took everything out of the closet....cleaned and disinfected all surfaces......removed the top 2" of soil......replaced w/ new mix of soil........watered in w/ hydrogen peroxide at 1 Qt to 4 Qt of water. I was told that the peroxide solution would kill the larvae. The larvae that was in my soil to begin with really caused the plants alot of problems. They have slowly turned yellow, wilted and stunted.

My questions are:

Is the peroxide a good solution? I also ordered some Gnatrol, but will take about a week to get to me.

If I can get the gnat problem under control, what long lasting effects will this have on my little crop of girls?

What else can I do to help w/ the recovery of the roots, etc.

Here is some general info on my grow:

Lighting - 4' 8 bulb T5 lights
Soil - 50/50 soil/perlite
Fertilizer - Earth Juice Grow every other watering
PH - 6.7
Temp - 74 - 87F - I know, that's a big swing
Schedule - 18/6
Age - 31 days from sprout


I've always had such great help here. Please give me any suggestions to help these girls recover. Thanks.

[Ganja Guerrilla]

scrape off the top layer of soil, water the soil with neem oil put new soil in the pot
sprinkle garlic powder on the soil and yellow sticky traps on the soil surface work well

[kbfl0912]

Thanks for the tips. I will try them. I already scraped the top layer of soil. Need to make a trip to HD. Since I just watered w/ the peroxide solution, should i wait until my next watering before using the neem oil, or should i just go ahead and water again? i would think overwatering could aggravate the problem.

[Ganja Guerrilla]

you can wait till next watering, fungus gnats are more of a nussiance than anything

you need more air circulation or the gnats wouldnt arrived

[kbfl0912]

I believe I brought the gnats in from the soil. The bag had been previously opened and I think the larvae was already in there when I planted them. Thanks for your help!

[Grower27]

Your grow is so much like mine, except I'm using four 2' t5's and my soil is probably crappier.
I have gnats, too.. And I finally got my Gnatrol 2 days ago. I used it once as directed, but still see the little buggers crawling around... I feel like pouring the Gnatrol right into the dirt, I swear!
And yeah, my plants are growing very very slow....

Good luck!

[eyec0n]

growing in crappy soil would make it grow very very slow. Did you add anything to it like perlite or sand?

[Grower27]

Originally Posted by eyec0n

growing in crappy soil would make it grow very very slow. Did you add anything to it like perlite or sand?

Was that directed at me? Cause the OP said he used perlite... No, I didn't add anything..

[kbfl0912]

Yes, I used a good organic potting mix and perlite...about 50/50. But the organic mix that i used had previously been opened (by me) and i believe that is how the gnats got in.

So, Grower27......the Gnatrol didn't work. that sucks....i am going to go by some neem oil tomorrow and see if that works as GG suggested.

When I scraped the top 2" of soil off, some of the roots were exposed and i could really see that they were small and not very healthy looking. the larvae really did a job on them. apparently they are sucking all of the nutrients out of the plant too because i am fertilizing more than i normally would and they still look N deficient. i haven't had a problem with any pests before, but these gnats are bad because of the many cycles they have. i thought i had them under control when i couldn't see any adults flying around any more...then bang...they all hatched and went crazy breeding again. i heard w/ gnatrol that you have to use it weekly to catch them in all of their stages. good luck w/ your grow. keep me posted if you find something that works great for you.

[Grower27]

Well I've just used it the one time.. First application. Tomorrow I'll do another application.... It's supposed to take a week to eliminate them.
Then, yeah, you're supposed to reapply monthly after that.
The good thing about Gnatrol (or so I heard) was that it didn't harm your plants.

Hey, I checked out your grow journal for your last grow... That was awesome seeing them go from sprout to full harvest... How did they turn out? Was that all T5 lighting? Did you use 3000k for bud? ... Well, I'm sure you did, but how did it go? I have 4 3000k lights ready to go when it starts 12/12.

[SinjinDamaja]

How bad are these things really? i just pulled like a week ago my first one and i noticed when i checked the roots they where brownish and they had these gnats everywhere.When i asked about this on these forums i was told that it just means i got good decomposition in my soil that I shouldnt worry. I first noticed them towards the last 2 weeks of the grow. but i know my new ones have them.

Will they affect yield and growth if in the soil early in flower?

my last ones got infested toward end thats why i ask.

[Ganja Guerrilla]

it just means i got good decomposition in my soil that I shouldnt worry.

what it means is you need more air circulation and you water too much too often



they are more of a nusiance than anything , but the larve does eat the tiniest of the roots

who knows possibly these attract other insects not so easy going on the plants....

& you can get infested!

[kbfl0912]

I've read that the "gnats" aren't the problem, but it's the larvae that cause damage to young plants. I think the older the plant, the less you have to worry about, but the younger ones....the larvae can really cause problems. They survive on the roots. They hollow them out, so the plant is weakened and stunted. The older plant would have larger, stronge roots.

here's a good article on them: http://everything2.com/index.pl?node_id=1388265



I had such an infestation that when i lifted up the pots, there were patches of solid black (gnats). So, i know they just laid about a billion eggs and that is why i am worried. my plants have been really stunted by the first round of these larvae. this will be the second round so i need to do something quick. i am going to use the neem oil and cover the tops of the pots w/ the sticky paper. this should break the cycle.

[kbfl0912]

Originally Posted by Grower27

Well I've just used it the one time.. First application. Tomorrow I'll do another application.... It's supposed to take a week to eliminate them.
Then, yeah, you're supposed to reapply monthly after that.
The good thing about Gnatrol (or so I heard) was that it didn't harm your plants.

Hey, I checked out your grow journal for your last grow... That was awesome seeing them go from sprout to full harvest... How did they turn out? Was that all T5 lighting? Did you use 3000k for bud? ... Well, I'm sure you did, but how did it go? I have 4 3000k lights ready to go when it starts 12/12.

Yes, I used the T5's for the whole grow. I have 8 bulbs. I used the 6500K for veg and the 3000K for flowering. I accidentally deleted all of the pictures from the last posts that showed the final product. I got about 5ozs. dried from those four plants. Not that great, but it was my first full grow. The White Rhino was great!

[Grower27]

Sweet! I'm only using four 2 foot bulbs.. But I only have 2 plants.. I hope it's enough light for them.