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Is this amount of fungus gnats a problem?

snack420

Well-Known Member
So, when I was watering my plant a few weeks ago I noticed some flying insects and after some research identified them as fungus gnats. Hopefully that is correct, but this is my first grow so I'm not totally sure.

Anyway, I've since added some yellow sticky traps on the top of the soil and also on the tent floor and they have caught some of those buggers, but I'm wondering if this is sufficient to address the problem? Also, can we tell from the number of caught gnats whether there is a real infestation problem or not? I do not see any visible issues with the leaves themselves, on either sides.

Here are some pics of the sticky traps with the caught gnats. Any suggestions on whether the gnats look to be a real problem would be great. More info about my grow can be found in my journal (see signature).

Thanks very much!!!

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Spimp

Nug of the Month: August 2013, June 2014 - Member of the Month: Oct 2013
I had gnats my first grow, and have some now.
Mostly they are just an annoyance. But if the numbers steadily increase they can become a real problem. If you grow healthy strong plants it will not be an issue imo. They will decide to move on to easier food.

However, If you would like some advice on getting rid of them, Sierra Natural Science offers several 'natural' cures/remedies. And they are a sponsor! :thumb:

Sierra Natural Science
 

snack420

Well-Known Member
Thanks for the feedback Spimp! At this point I don't think I'll worry too much about the gnats, but if their numbers increase, I'll get some SNS (213 I believe).

Also, since this is my first grow and I'm a little unsure of whether my plant is really good and healthy, I'm including a picture of it for any opinions. Thanks again.

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Spimp

Nug of the Month: August 2013, June 2014 - Member of the Month: Oct 2013
First off, don't worry about the yellowing lower foliage. That's natural culling done by the plant.
I do have a concern though.
The color of your plants looks very healthy, but the leaves should be more Vibrant and standing straight out, In the picture they look to be drooping some.

What is your watering schedule? Are you letting the plant dry out a lot before watering? Overall she looks good though. Nothing to panic about. ;)
 

snack420

Well-Known Member
Well, I'm glad you mentioned the droopiness because I also thought my plant seemed less vibrant that it should.

My watering schedule initially was once every few days, but soon I noticed some yellow mushrooms growing in the coco and also some fungus gnats. I read that moist topsoil can encourage these problems, so I let the soil dry out and sought some alternative watering solutions. Since I sometimes cannot attend to my grow for several days a time, the hydro shop suggested the "blumat" solution, which is an auto-watering system. It is very simple. Basically, it is an attachment you can put on a standard plastic water bottle opening and it allows the water to drain into the coco as needed by the plant. I thought this was a great solution for me, given my schedule, and also because it allows the topsoil to stay dry, but maybe it is causing an over-watering problem??? For now, I've removed the water bottle and will let the coco dry out for a day or two. Is that what you'd recommend at this point? Should I abandon the blumat watering system and water them with a watering can every few days instead?

My plant is getting near 1 foot tall now (measured from the top of the pot), so given the space limitations of the tent and the expected growth in the flower cycle, I was planning to switch it to flower either this weekend or next. I FIMed it for a second time last week with the hope that it would split colas and there is new growth, but I'm not sure if there will be multiple colas yet. (I FIMed it about 3 weeks ago but it didn't split into multiple colas so I suspect I didn't cut it low enough on the new growth.)

Thanks for letting me know that the yellowing flowers I showed are not a concern. I clipped them with the thought that they were dying anyway and that I should remove them so the plant doesn't have to divert unneeded energy to them.
 

coconutunococ

New Member
i'm a total gnat nazi. Any is too many in my eyes. sometimes it can be hard to completely eradicate them, but I do my best. hate the idea of those bloody little bastards devouring the roots on my precious girls.
 

Spimp

Nug of the Month: August 2013, June 2014 - Member of the Month: Oct 2013
I don't have any experience with coco so any advice would just be guessing. Here is a link to a forum that should help COCO GROWING

p.s. At this point you are just 'fine tuning'. Looks pretty good to me. :thumb:
 

snack420

Well-Known Member
i'm a total gnat nazi. Any is too many in my eyes. sometimes it can be hard to completely eradicate them, but I do my best. hate the idea of those bloody little bastards devouring the roots on my precious girls.

Yeah, I don't like that there are any of the gnats either, but I get the impression they are very hard to completely get rid of. Not really sure how they are evening coming into the garden, but probably latching onto me when I come in from outside. I'm going to rely on the sticky traps for now and step up efforts if they seem to increase.
 

snack420

Well-Known Member
I don't have any experience with coco so any advice would just be guessing. Here is a link to a forum that should help COCO GROWING

p.s. At this point you are just 'fine tuning'. Looks pretty good to me. :thumb:

Cool, thanks Spimp. I'm going to look over the Coco forum and see if I can learn more about my situation. I agree it seems to be doing fairly well, but I'm a little concerned about the droopiness and am going to let the coco dry out for a couple of days and see what happens. Thanks again!
 

brightlight

Grow Journal of the Month: March 2017
Yeah, I don't like that there are any of the gnats either, but I get the impression they are very hard to completely get rid of. Not really sure how they are evening coming into the garden, but probably latching onto me when I come in from outside. I'm going to rely on the sticky traps for now and step up efforts if they seem to increase.

Welcome to 420 snack. I've only had fair success w/ SNS 203. SNS told me to up the dose to 2x/3x the recommended dosage on the bottle. I didn't care much for that advice so only use it for very light infestations. The BEST thing for gnats in my experience are beneficial nematodes. Not that costly and more likely to eliminate than suppress like the drenches. Best type for gnats are Steinernema feltiae since they mostly live in top 3", which is where the gnats concentrate.
 

kikocorn

New Member
My first grow had these, I added a layer of arogonite(like beach sand) i got at the pet store on top of the soil. It'll keep the top of the soil dry and get rid of them and kill their eggs. Just water really slow so you dont have to keep adding more sand.
 

SWIM

New Member
Bti will sort them out! Reapply every 5 day until you see no more, usually two or three reapplications. The larvae ingest the bacteria which produce a toxin that inhibits the ability of the larvae to digest any food, leading to their rapid death. Good times!!!
 

snack420

Well-Known Member
What's is BTI? Thanks!

Bti will sort them out! Reapply every 5 day until you see no more, usually two or three reapplications. The larvae ingest the bacteria which produce a toxin that inhibits the ability of the larvae to digest any food, leading to their rapid death. Good times!!!
 

snack420

Well-Known Member
Welcome to 420 snack. I've only had fair success w/ SNS 203. SNS told me to up the dose to 2x/3x the recommended dosage on the bottle. I didn't care much for that advice so only use it for very light infestations. The BEST thing for gnats in my experience are beneficial nematodes. Not that costly and more likely to eliminate than suppress like the drenches. Best type for gnats are Steinernema feltiae since they mostly live in top 3", which is where the gnats concentrate.

Cool, I'm going to look into beneficial nematodes. Sounds very interesting. Thanks for the suggestion!
 

snack420

Well-Known Member
So, I went to the hydro store yesterday, looked over pictures with the very kind guru there, and he convinced me the droopiness is most likely due to the fungus gnats, which kind of had me panicking a bit. Anyway, sounds like it is recoverable and he recommended the SNS 203 which I applied last night; 4oz with 1g of pH'd tap water and poured very slowly over the coco.

I mixed up a fresh batch of water with nutes, half the full strength recommendation on the bottle (Flora Duo A, B, CaliMagic, RapidStart, Floralicious) and brought the pH down from about 7 to 6 using some drops of pH down. I mentioned to him that I abandoned the blumat auto-watering device because several people recommended letting the plant have a dry period, but he said that coco is different than soil in this regard and dries out much faster and typically should get watered more often and suggested I use the blumat, so I am giving it a try again. I also added a couple of new yellow sticky traps on the top of the soil and on the tent floor and since last night no gnats have been caught or were visible to me.

I will check in on her this weekend and with any luck she'll be in better shape. I will say that this morning she seemed a little bit perkier, but I don't want to get too optimistic yet since I'm not 100% sure what was/is wrong. Thanks for all the suggestion though - they are much appreciated. I'll update this thread with her health in a couple of days.
:Namaste:
 

snack420

Well-Known Member
So, I'm happy to say that she seems to be recovering quite nicely from the SNS 203 soil drench on 7/9 and is looking much more perky than droopy, which is great news. I also applied a couple of new yellow sticky traps which caught two gnats on (I believe 7/9), but no new one since them. I'm hopeful that the gnat situation is nipped in the bud, so to speak, but I guess time will tell. Without further ado, here are some pics...

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:peace:
 

finkelroy

New Member
One word - nematodes. You can buy them online from a company called Ladies in Red. They also sell ladybugs and preying mantis eggs.
You put the nematodes in the soil and they eat the larvae of the fungus gnats. The gnats may never totally go away (and likely won't with chemicals either), but you can avoid damage to your roots and having great swarms of them in your house by using the nematodes.
0.5% peroxide concentration in your water will also help to suppress them.
 
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