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why do i have fungus gnats?

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why do i have fungus gnats?

imgrowing 38 Replies 4,699 Views
Page 2 of 2 · Replies 21–39 of 39
#21
Well I'll be darned. Mosquito bits. It's not a jar full of pieces of mosquitos......

And as a bonus, the pieces look like little tiny people!
 

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#22
Drgreenthumbs1 said:
Fungus gnats eggs sometimes come in store bought soil mediums. There’s just no way to avoid them sometimes even when you’re drying down properly. Water with BTI and they’ll be gone in 3-4 days. Keep watering with BTI and they’ll never come back
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This!!! BTI is great, one of the many good reasons i use Great White inoculations.
 
#23

Bacillus thuringiensis israelensis…​

Google mosquito bits or dunks. Thank me later.
 
#25
cannafarmer420 said:
A tip I learned was to open your soil bags and dry them out for a couple weeks and if any gnats came in the bag, that drying process will kill the babies.
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This is why I open all of my bags of dirt and put the stuff in totes with holes drilled in the lid, i work out of that instead of the bag. I always let it breath before using, my feed shop that supplies my dirt has coverage for their stock, but the bags still get wet from time to time, so if you do this and check it out real good you can dodge the bullet. If I open an active bag, I’ll snap photos, and drag the bag to the feed store to swap no questions asked. My feed store and I have a many years long relationship at this point, but I’m sure any good vendor would do the same. It’s a bitch, but worth it.
 
#28
Or instead of any of all that stuff assuming you are in soil you can scratch in cinnamon and top dress, be sure to turn fans off when you apply and spray the cinnamon with a little water so it doesn't get air born once you turn the fan(s) back on..

kills larvae and adults won't survive if they land in it.. as a bonus roots love it!
 
#29
alpha.ganjaguy said:
Or instead of any of all that stuff assuming you are in soil you can scratch in cinnamon and top dress, be sure to turn fans off when you apply and spray the cinnamon with a little water so it doesn't get air born once you turn the fan(s) back on..

kills larvae and adults won't survive if they land in it.. as a bonus roots love it!
Click to expand...
Some swear by peppermint essential oil around the rims of your pots.
 
#30
imgrowing said:
everything i've ever read said unless you over water and have wet soil for a long time fungus gnats won't be a problem.
i'm really careful about the wet dry cycle and yet i have them.
treated with DE and a layer of perlite and then sticky traps today.

why would i have them after being so careful?
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To paraphrase Clint Eastwood, "Careful's got nothin' to do with it." It's because of fungus gnats that scientists used to have a "Spontaneous generation" theory. Because of how fast the little bastards show up, science used to think they just appeared from nowhere.

I bought some rove beetles and beneficial nematodes and it completely wiped them out.

But what I think really worked the most was the nematodes. https://a.co/d/3Lze5Np

I didn't mix it with water - ohh, no. I divided it amongst all the plants by pouring it on well-watered soil and working it into the top inch or so, then mulching so they stay happy the first few days after activation.

In a couple of days the fungus gnat population dropped dramatically. In a couple of weeks they were all gone. A few days ago I planted a couple of plants in some compost that hadn't been treated, and now I have fungus gnats again but it's not an infestation.

Personally, I don't think it's worth the trouble to completely wipe them out. They won't hurt your plants (or tender little seedlings!) unless there are a lot of them. Besides, if you see them now they're probably going to keep coming back. I just tell myself they're not spider mites and that keeps me relatively-happy. Once I shut down my grow completely because of those little phuckers (spider mites, not fungus gnats).
 
#31
Oh yeah, I forgot the mustard seed. I applied it first and it wiped out a bunch of them. I applied it too liberally though, and killed off the seedlings the fungus gnats didn't eat.
 
#32
ok thanks for the responses.
now onto the next dilemma, what i've done so far looks like it's working as i have no new pricks on my sticky traps, i've also added mosquito pucks to my water pail.
my girls need water tomorrow or the next, but that will destroy the DE.
will 2 or 3 days be enought for the DE to work?
 
#33
imgrowing said:
ok thanks for the responses.
now onto the next dilemma, what i've done so far looks like it's working as i have no new pricks on my sticky traps, i've also added mosquito pucks to my water pail.
my girls need water tomorrow or the next, but that will destroy the DE.
will 2 or 3 days be enought for the DE to work?
Click to expand...
I top dress with de all the time I find it best to put on the day after watering (about 1 tbs evenly spread ) and scratch into the top 1/4” might do it every 3-4 waterings works well for awhile but it’s your best defense wet or dry I I also mix it right I do my soil when amending

I have a soil bin (huge Rubbermaid) so I’ll mix that with de then let it sit for … however long until I need it seems to do the trick nowadays I hated to get them, I got them nonstop before I did this method
 
#34
rasterman said:
To paraphrase Clint Eastwood, "Careful's got nothin' to do with it." It's because of fungus gnats that scientists used to have a "Spontaneous generation" theory. Because of how fast the little bastards show up, science used to think they just appeared from nowhere.

I bought some rove beetles and beneficial nematodes and it completely wiped them out.

But what I think really worked the most was the nematodes. https://a.co/d/3Lze5Np

I didn't mix it with water - ohh, no. I divided it amongst all the plants by pouring it on well-watered soil and working it into the top inch or so, then mulching so they stay happy the first few days after activation.

In a couple of days the fungus gnat population dropped dramatically. In a couple of weeks they were all gone. A few days ago I planted a couple of plants in some compost that hadn't been treated, and now I have fungus gnats again but it's not an infestation.

Personally, I don't think it's worth the trouble to completely wipe them out. They won't hurt your plants (or tender little seedlings!) unless there are a lot of them. Besides, if you see them now they're probably going to keep coming back. I just tell myself they're not spider mites and that keeps me relatively-happy. Once I shut down my grow completely because of those little phuckers (spider mites, not fungus gnats).
Click to expand...
The key is to get them in before there's a problem.
 
#35
I pulled this from another forum, just be careful with DE

"One factor to consider when you use DE is the arsenic content. Diatomaceous earth has some of the highest arsenic levels I've seen in any soil product/amendment/fertilizer etc. It varies from brand to brand of course, based on which deposit it came from, but it's high enough to fail heavy metals tests for commercial growers if they add it to their soil. The CDFA Fertilizer database only has a single DE listing because the dangers of it really isn't on any important people's radar right now so no one is testing it-go here and next to "product" type "diatomaceous" and you can see the single listing they have is quite high in As. I think for most people who use it sparingly to kill insects, it probably won't build up all that much in the final product. But I've seen a trend lately where people want to add DE for the silica or some other such reason, and that's where it becomes a problem. Plus, it's just not good to use it indoors-any mixing of DE, rock dust, perlite, etc, should be done outside-none of those dusts are good for your lungs. Good luck to you!"
 
#38
rasterman said:
Sure. The company that sells them recommends buying some for every grow. I wish I could do that...
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I grab mine from Natures Good Guys, they seem to be the most reasonably priced around here.
 
#39
Anyone here (growing in pots) experiment with landscaping weed barriers to prevent fungus gnats?
I don't have the problem, that comes when garage season opens, (month from now) and I've found a product that kills them dead in their tracks, the whole cycle, larvae to adults. Azamax.
Just wondering if a simple landscape weed barrier can help.
 
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