Soil drench for fungus gnats

doug mirabelli

Well-Known Member
i bought this product sns 203 as a soil drench. I took a pic of the ingredients. I’m 6 weeks into flower. Also got some gnatnix which I’m Definitely using as a top soil. Should I hold off on the soil drench? I’m worried about a funky taste for the final product. Also I feel like it’s made more for aphids. Any input?
 

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Mafiaal

Well-Known Member
I'm having a gnat problem now myself, I've started with Garden safe neem oil and did a spray along with putting out sticky pads all over.
Still saw a good amount in the soil this morning, I'm going to replace a few inches of soil from the top and use DE plus some fine aquarium rocks to see if i can break the life cycle.

If that doesn't work I've read about this product called old stage green clean.

These things are a PITA!
 

Chunky Stool

Well-Known Member
Seeing an adult fungus gnat once in a while isn't a big deal because they do zero damage to your plants.
Adults lay eggs in damp soil, and that's where the damage begins. Their larvae burrow and feast on roots -- while carrying fungal badness with them.
Then they hatch and the process repeats.

(NOTE: This is not true for thrips, which can look similar.)

So what does all this mean?

Controlling fungus gnats is a process, not an event.

Contrary to popular belief, you CAN control them without letting your medium totally dry out between waterings. That's where the biologicals excel, but you've gotta use them each time you water.

My soil is a death trap for fungus gnat larvae, so I don't mind seeing an adult once in a while.
They can't multiply and will eventually die off. 8)

(Again, adults do *not* damage plants.)
 

hillbill

Well-Known Member
I watered with Gnatrol and the problem has disappeared. Available again on EBay in small amounts. Worked very fast. Now I water maybe once in flower with 1 tsp/gal.
 

Mafiaal

Well-Known Member
So after the first round of Neem oil via spray i saw a major decrease in Gnats on the plants but it took 4 rounds of spraying plus clearing out the first couple of inches of soil with fresh soil, covering it with DE and using fine river rocks. Almost all are gone now.
Sticky pads worked well too.

I took this opportunity to repot a little deeper and add some Mykos from xtreme gardening so it all worked out.
 

DonTesla

Well-Known Member
You are so far along and so close to the goal.

I would just drop some DE Rocks down (NOT powder!) and top those with some clean sand.. Not a gnat in the world that can get through a few inches of that.

Then the pupae cycle will be interrupted .. and they won't be able to survive/thrive. Meanwhile, your air roots will be thriving / thanking you.

And switch to bottom feeding for a week too, to give them extra hell.
 

Zero_OS

Well-Known Member
I use mosquito bits and have zero problems with gnats. 1 tsp / gal and you're golden. Just let em soak a few minutes before watering.
Mosquito bits didn't work too well for me (tried direct application to soil and soaking in water). So I used mosquito dunks, crushed them and put some on the soil surface, then covered with 1/4" soil. Solved the problem. I think the mosquito bits don't have as much bt as the dunks, as they are mostly corn kernels.
 

Chunky Stool

Well-Known Member
Mosquito bits didn't work too well for me (tried direct application to soil and soaking in water). So I used mosquito dunks, crushed them and put some on the soil surface, then covered with 1/4" soil. Solved the problem. I think the mosquito bits don't have as much bt as the dunks, as they are mostly corn kernels.
Gotta soak em.
I add mosquito bits first so the anti-bug goodness can disperse in the water before applying to soil.
It doesn't take long, 5 mins max.
-- edit --
I should also note that freshness matters when it comes to mosquito bits.
I bought an old jug with a faded label and it definitely didn't work as well.
The fresh stuff will have a sweet smell when you open the lid, like candy or molasses.
 

Zero_OS

Well-Known Member
Gotta soak em.
I add mosquito bits first so the anti-bug goodness can disperse in the water before applying to soil.
It doesn't take long, 5 mins max.
-- edit --
I should also note that freshness matters when it comes to mosquito bits.
I bought an old jug with a faded label and it definitely didn't work as well.
The fresh stuff will have a sweet smell when you open the lid, like candy or molasses.
Yeah, the direct app did not work. I soaked for 2 hours, then watered (did this multiple times)...still not that effective. I probably had an old batch, but now that I have tried the dunks and seen how effective this method is, I swear by them
 

doug mirabelli

Well-Known Member
What’s the best method for removing the gnats from the buds? I’m
Swarmed with gnats. Tried to vacuum them out with a heavy duty vac/blow. I put down some gnatnix but that did t seem to do much I should have bought two bags. I got 8 7 gallon pots to fill. Traps are full with them I need to get more. Not really sure what to do 7th week of flower just going to power through. Try to vacuum the bugs after drying or bud wash before drying. Might try both methods
 

Thegermling

Well-Known Member
What’s the best method for removing the gnats from the buds? I’m
Swarmed with gnats. Tried to vacuum them out with a heavy duty vac/blow. I put down some gnatnix but that did t seem to do much I should have bought two bags. I got 8 7 gallon pots to fill. Traps are full with them I need to get more. Not really sure what to do 7th week of flower just going to power through. Try to vacuum the bugs after drying or bud wash before drying. Might try both methods
I think youll end up damaging lots of trichomes with the vacuum (I could be wrong). Gnatnix should cut the Gnats up. If you went to my thread about fungus gnat control then you should have read that using three or more of the techniques to combat fungus gnats should work. I used gnatnix (larvae and flies), yellow sticky traps (for flies), and BTi (for larvae) and I was successful in stopping infestation.
 

hillbill

Well-Known Member
Rinse your buds at harvest to remove most as trichs are not bothered by water. I used dunks for years and mostly “contained” gnats. Ordered Gnatrol and watered in and most gnats were gone in a couple days. Similar to dunks but also has the toxin produced by the bacteria. It is hot humid summer here and no gnats. I use 1 tsp per gallon every few weeks for maintenance.
 

Chunky Stool

Well-Known Member
Rinse your buds at harvest to remove most as trichs are not bothered by water. I used dunks for years and mostly “contained” gnats. Ordered Gnatrol and watered in and most gnats were gone in a couple days. Similar to dunks but also has the toxin produced by the bacteria. It is hot humid summer here and no gnats. I use 1 tsp per gallon every few weeks for maintenance.
Rinsing your harvest is a very good idea.
I use two 18 gallon totes and do a double rinse.
Cut big branches, remove fan leaves, rinse, then hang to dry.

EZ-PZ
 

doug mirabelli

Well-Known Member
Rinsing your harvest is a very good idea.
I use two 18 gallon totes and do a double rinse.
Cut big branches, remove fan leaves, rinse, then hang to dry.

EZ-PZ
Rinse your buds at harvest to remove most as trichs are not bothered by water. I used dunks for years and mostly “contained” gnats. Ordered Gnatrol and watered in and most gnats were gone in a couple days. Similar to dunks but also has the toxin produced by the bacteria. It is hot humid summer here and no gnats. I use 1 tsp per gallon every few weeks for maintenance.
I’m too afraid this late in the game to add anything to them so I’m just going to power through.

I’m going to try bud washing I hope it removes all the bugs. I can find anywhere online that showed someone with the same problem as me. I have so many bugs stuck to my buds it’s scary. I’m going to wash but I’m nervous that it won’t do the trick.
 

ACitizenofColorado

Well-Known Member
My 2 cents: gnatnix isn't a viable option in my experience. Try beneficial predators.

Chunky stool is on point.

Gnatnix is dusty. I use fans below the canopy, and became very concerned about the fans blowing dust up and onto flowers. In the end, I couldn't take the risk.

Are you doing hydro or soil? A convention often repeated is, if you have gnats, let the soil dry out significantly, then let the soil dry out in between watering. Drying out the top of the soil creates an inhospitable environment for the fungus gnat larva, disrupting the life cycle of the fungus gnat.

But there's a delicate balance. I often couldn't dry the soil out enough to completely eradicate the fungus gnat larva, thus the adults. Also, drying the soil out so much seemed to impact my growth. It's not that I noticed significantly less growth between traditional water from top or bottom methods and letting the pot dry out enough to kill the gnats. It's that once I started using a SIPS pot, which creates a constant level of soil moisture and avoids the drying cycle, my growth exploded.

You're already where you are. Many people speak highly of gnatnix. After throwing away the entire half of a canopy due to concerns about gnatnix drifting up and settling on flowers, I decided to figure something else out.

I use predator mites like rove beetles and hypoapsis miles/mites. I have used nematods; it's possible they are still there, but I can't tell.

I've had the same crop of rove beetles for nearly a year and a half. I chopped, put the smart pots in trash bags for a few months, opened the bags and saw that the rove beetles survived. Every time I transplant something into another pot, I put a few rove beetles into the new mix.

Grab some sticky traps; put fans below your canopy, blowing on top of the soil; use and repopulate new pots with predators.

I'd hope you can salvage this one, and that in the future you can keep populations down.

I wish more people would look at this issue with me:

for anyone that has every moved their hand through a bag of gnatnix or tried to put that stuff in pots that already have flowers, how does one keep that powdered glass from blowing up into the flowers?

The only option is to have no air movement below the canopy to prevent the gnatnix from being disturbed and, potentially, ruining the flower.

I'd rather have fans above and below the canopy, beneficial predators, and sticky traps.

Good luck.
 
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