Fungus gnats in my soil....

Discussion in 'Organics' started by Thai_Lights, Nov 26, 2017.


    Thai_Lights Well-Known Member

    Whats the best way to get rod of em? Jjst sprinkle DE on top of my mulch?

    Thai_Lights Well-Known Member

    I have h202 also.... will this damage my microherd?

    green_machine_two9er Well-Known Member

    I like to mix the de with perlite and coco coir. Helps to keep an inch or so of dry stuff. I usually do 2 or 3 tablespoons per gallon of coir/perlite. Works well for rols pots. Gnats will disappear

    DonBrennon Well-Known Member

    I can't imagine h202 being good for your 'microherd' for the exact reason it's good for getting rid of FGnat.

    BTi is your best friend here 'I believe', I've done some 'asking around' recently as to if it also harms other 'bennies' in your soil, with no definitive answers, BUT it's the only thing that has decisively worked for me in the past.

    I've currently got a FGnat infestation that put all my others in the past to shame, I've got millions of the fuckers!!! Problem is BTi is banned here for some reason(I think it's purely a precautionary measure on an unproven link to the decline in bees, everything is getting banned here ATM except roundup apparently FFS), I've tried the nematodes and they seemed to make things worse, so I've ordered some BTi internationally hoping they get through customs.:neutral:

    Hope ya get things sortedbongsmilie
    DonTesla likes this.
    Richard Drysift

    Richard Drysift Well-Known Member

    Diatomaceous earth for the win. Let the soil dry out a bit and then sprinkle the DE as heavy as you like on top of your mulch. Use DE as a soil amendment as well which is actually a good source of silica once it breaks down. Don't use h2o2; that's only for cleaning your cloner or hydro system.
    Adding neem seed meal to your mix globally when you recycle helps stave off gnats and leaf munchers like thrips as well. Neem seed meal gives your plants a natural defense but nothing is more effective against gnats as a dry top layer of soil; they hate it. Try watering from the bottom for a couple weeks if you can.
    MrKnotty likes this.
    Canadain Closet Gardener

    Canadain Closet Gardener Well-Known Member

    I'm going to be trying this.
    Water with Dunks for 2-3 weeks then i'm going to add Nematodes. I also have been using yellow sticky traps.
    I would suggest getting your sticky traps from ebay / china. For around $20 cnd I got around 50 full size sheets. Each sheet has more surface than a pack Safers Stick strips. I just cut them up to size.
    They are also sticky on both sides.
    I've been spreading DE too and have a little bowl of Apple Cider to drown them.

    psychedelicdaddi Well-Known Member

    1"-2" of sand and add BT to your water every so often. BT is typically sold locally at farm/tractor stores.
    Bubba's girl

    Bubba's girl Well-Known Member

    Is BTi not the same thing as Mosquito dunks? Are do I have the wrong?

    RandomHero8913 Well-Known Member

    Same thing. Mosquito dunks contain the bacteria BTi.

    psychedelicdaddi Well-Known Member

    Doesnt seem to harm my teas and still works against the gnats. I just mix BT, EM, and fpe + a few T molasses, aerate for 24hours. It also can be put in a spray bottle by itself and just mist the soil line after watering. Im doing both with much success.

    MrKnotty Well-Known Member

    DE is awesome, u could also make a garlic and lavender extract and root drench with no problem
    mr. childs and DonTesla like this.

    DonTesla Well-Known Member

    Diatomite : DE Rocks.jpg

    3 inches of DE Rocks, not powder, is what I would do, that would allow you to keep on watering from the top..

    as mentioned, can use

    Sand etc
    wicks for watering from the bottom

    as well as potato slices one inch thick to trap larvae

    lots of airflow,

    blue and yellow sticky traps,

    slightly lower temps,

    garlic cloves planted in a circle around the stem of main plant,

    and if you are due for a re amending, try adding fresh worm castings, careful to keep totals under 25% which is best in my personal opinion

    I don't use hydrogen peroxide in my garden, but thats me.

    Thai_Lights Well-Known Member

    Don where' the best place in Canada for DE rocks?

    Danielson999 Well-Known Member

    I use organic soil which pretty much means you'll be dealing with fungus gnats. You need to break their cycle of life. This means if you treat your soil with h2o2 or whatever else, you still need to deal with all the living adults that are hiding on your plants leaves or sitting in the corner of your tent. This is where the big yellow sticky traps work well.

    H2O2 will kill microbes but you don't need to drench your entire pot with it. You can spray-soak the top of your soil with H2O2. Spraying some neem oil on top of the soil also works great. It fucks with the gnats ability to reproduce and function.

    This is all just making your environment inhospitable to gnats. You can put sand on top of your soil. Have fans blowing air around your pots. Whatever you do, make sure you use several techniques because there is no ONE technique that gets rid of them all.

    The best thing I ever did was to start bottom feeding my plants. I have 5 gallon smart pots sitting in 18" round trays. I pour water into the tray and let it sip up into the soil. This lets the top of the soil dry out which effectively stops your gnat problem.

    I tried using mosquito dunks and it never did solve the problem. It helped a bit but wasn't a cure for me. Gnats will almost always be a possible issue for me using organic soil. Hell, they come in the bagged soil I buy so as soon as I water the first time they start their life cycle. Now that I bottom feed my plants and spray-soak the top with H2O2 and neem oil and have good air circulation around my pots and use sticky traps, I have no fear of fungus gnats ever again.
    Last edited: Dec 1, 2017

    stoned-monkey Well-Known Member

    I have done what everyone else has mentioned, bti, sand, de, sticky traps, h202, neem, fans. the level of effectiveness varies each time.
    Prevent-big thing is dry top layer, sand has cause ph issues for me so I like perlite. de is just plain helpful for a lot so mix that with your dry top layer as well as Bti (I use the bits, same as dunks but already broken up), fans I thought everyone already kept fans moving air below canopy, you probably want to if not.

    spot-sticky traps are my warning signs, I see gnats I go to treatment,

    kill-neem works sm90 works spinosad works, h202 works, probably a million other things too, pick your "poison" and I like two different kinds. hit with one then 3 days later hit with the next then repeat one more time. should be over for now. if in full flower do not spray the buds... root drench sure.

    517BlckBerry Well-Known Member

    check out some PYGANIC i love that product

    Fastslappy Well-Known Member

    U need soil Pred mites & nematodes , rove beetles work too best is all three u never have them again BT DOESN'T work
    Bubba's girl likes this.

    SchmoeJoe Well-Known Member

    Yes, in a big way.
    DonBrennon likes this.

    SchmoeJoe Well-Known Member

    Gnatrol. Check it out.
    DonBrennon likes this.

    Lightgreen2k Well-Known Member what I have done for fungus gnats..
    Sticky traps one
    Basically you can have either of these peppers and chop them done fine, and put them in a pot and let it simmer for about 30 mins. Use a strainer and spray your plants. One pound of those pepers will make four gallons worth of foliar..
    mr. childs likes this.

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