Organic Fungus Gnat Control

Discussion in 'Growing Organic Marijuana' started by jakrustle, Jan 3, 2011.

  1. I seem to be having quite an outbreak on my 4 week old girls. Could some of you guys remind me of anything besides spraying with Neem Oil that could be very helpful to get this under control?

    I have heard sprinkling cinnamon on the soil, letting your plants dry out well between waterings, and Chamomile Tea all help. I bought Mosquito Dunks. They are a Bti species, but I am scared to put it on my plant. Anybody ever hear of it, or try it??

    I have cinnamon and Chamomile Tea. How do you drench with Chamomile tea as far as mixing a solution? Brew a cup, cool it off and pour it on?? WIth the cinnamon, go very lightly??

    Any help would be much appreciated.

  2. Jak,

    There is little that I have experience in but this is one of them. I layed out one of the fly sticky pull out things across several pots and with in a few days they were under control. I must have had a thousand stuck to it within a week, I guess they were hatching.
    Worked well and now I only have a few. I am hopefull that the neem seed meal in my new soil will control them in the future. ;)

    Evil T
  3. #3 colafarmer, Jan 3, 2011
    Last edited by a moderator: Jan 3, 2011
    Normally we bring the fungus gnat into our grow area. Finding the source of the gnat and eliminating and confining the enviroment they live and lay their eggs is key.
    A likely place outdoors is a compost pile, extra unused potting soils, soil recycle area, fruit trees, etc and in general places that are humid, moist and provide a cozy enviroment for the adults to lay their eggs.

    Once in the soil with plants the larve can feed on young roots and affect healthy growth.
    At this point, if heavily infested you can look around for a soil drench for gnats that will not harm the microbes or, or organic matter and drench the soil.
    Place yellow sticky cards on the surface of potted plants to attract and kill the adults.
    When the soil has dried out some growers will place 1" of sand on the top of the container soil to eliminate the adults access into the soil to lay their eggs.

    If you were growing with chemicals hydrogen peroxide is the best cure and provides oxygen to the roots, but will kill microbes and not recommended in an organic grow...
  4. I agree with all this. As I said in my journal but differently here; You wanna know when you hav a fungus gnat infestation? When you see ONE of those little bastards. They're everywhere around us hitching rides to and fro.

    I'm not putting anyone's home methods down to control these suckers but I think the only solutions are; neem seed, karanja seed, Bacillius Israelis (mosquito dunks). Some commercial products are things like Gnatrol (Bacillius Israelis) and a couple of others which names currently escape me.

    I'm on the hunt for the neem seed now to make a tea to kill the larvae. I wholeheartedly agree with colafarmer that these little bastards will wreck heavoc with the root system. They all must die - men, women, and the kids too. They can not be allowed to cohabitate indoors with our gardens! Kill 'em!

    (anyone get the idea that I absolutely loathe the lowly gnat)
    • Like Like x 1
  5. That Gnatrol is good stuff, but never seen any local. The mosquito dunk is awesome...Use a 1/4 of the dunk crushed up and disolved in a gallon of water overnight and drench the soil dose the trick. Just have to be sure you keep adults from geting back in the grow area...The stickies cards are good for that, as gnats are attracted to the color yellow..;)
    A foilar spray with Pyrethin helps but, not the best solution.
    As Possum says neem seed is a good ammendment to add to your soil mix for controlling disease.

    You can check the infestation in the soil by placing a slice of potato on the soil surface, keeping it moist by covering with a cup or, something. The larve will be dining on that potato...;)
  6. Nothing I can add to the above two post, except to totally agree

    I use the mosquito bits. But basically the same thing.
  7. Neem + surfectant seems to work. Also been using Garlic and Cinnamon recently, mostly for fungus prevention, but the garlic helps with insects as well.

    Also spiders do wonders for keeping them from taking hold.

    Keeping a well ventilated, well drained garden and not overwatering it.
  8. Guys, thanks for the suggestions. I have a Mosquito Dunk, so I am going to be using that this AM. I sprayed with Neem Oil last night, then sprayed the twins with clear water this am. I put about a 1/2" of pumice on the top of the soil because I had no sand. I have not watered them in a couple days now.

    Their next watering I will definitely go with the Mosquito Dunk. When I watered this AM, all I saw was one, but I know the little bastards are there. I had my soil wet in the garage for far too long before I did this planting. I know that is where I got them.

    I have not gotten the neem seed meal yet, but plan on it right now.

    Thats for the support guys. You know, these plants look GREAT at 4+ weeks and thinking about those larva in there eating up my roots has got me a bit worried. I go in the tent now and then hunting for the little fuckers that are on the wing. I come out smiling every time I kill one.
  9. Ironically enough i had a similar problem, the gnats weren't out of control really just a few here and there that annoyed me, i ended up lucking out and found 3 daddy long leg spiders which i let set up shop on the bottom of my pots to web and kill and eat any insects they could, since they don't harm my plants they are more than welcome to hang out with my girls =)

    Unorthodox, yes very haha but did it work absolutely and i didn't end up with spiders in my bud either some insects are friends not many but daddy long legs and lady bugs will always be your friend =)
  10. Lightly spray the soil with neem oil mixed with water (same as you would use for foliar). I had a few gnats in my last grow, this took care of them quick like.

    Also top-dress/mix in some of that neem seed meal when you get it.
  11. Stankie, you know, I foliar sprayed them a couple times over the last four days with the neem oil. I have the soil covered with pumice now, also. I went in there today and just lightly foliar sprayed with water. What I am thinking is the heavy foliar might have dripped down on the soil, but I did think about a light spraying on the soil surface.

    I went out and got some sand and diatomaceous earth to put on my grow and my containers of soil out in the yard. I have a feeling I may have been contaminated from the soil I have stored out there from previous grows.

    I also have a 1/4 donut of the Mosquito Dunk soaking in a gallon of water. How long did some of you who used this let it soak for? This stuff seems to just float around the top of the container. Is there something microscopic going on that I don't see? Let me know if you have some experience. Thanks.

  12. I don't know about the mosquito dunk getting the fungus gnats. The gnats would have to land in the water. No?

    What I do know is the mosquito bits (which are like little granules of grain) contain a fungus gnat predator which eats those fucks, right in their home. baawaaaahahaaaa
  13. YG, the thing I heard to do is soak it in a gallon of water, then pour the water into the soil. Apparently, the bacillus are free swimming in the water, then get dumped into the soil to do their job. That's where I want to know I am doing the right thing. Thanks.

  14. Crush it up first and soak in water overnight....Soaking the crushed MD in hot water first and adding to water may be faster then, water throughly.
    I would not mist to often as the buds may form mold....The gnats will not bother the foilage. You just want to drench the soil and avoid the gnats from entering the soil.
  15. ColaFarmer solution make sense. My only comment would be not to make the water too hot because you are dealing with living things and not trying to make lobster :eek:
  16. Crustacean meal (crab, lobster or shrimp or some combination) will provide you with chitin (pronounced 'kite-in') and you can research that all over the WWW. It's probably worthless as a top-dress deal but 1 cup to 1 c.f. of potting soil will reap great rewards for a number of reasons like it's ability to trigger a plant's SAR (Systemic Acquired Resistance) as a start.

    Next up is neem seed meal (or karanja or a combination) - sprinkle about 2 tablespoons on top of your soil (top dressing) and water in with Dyna-Gro Pro-TeKt - no more gnats of any species. Ovah. Done. Finis.

    Better yet is to add about 1 cup to 1 c.f. of soil at the beginning of your garden cycle.

    Also the addition of any lactobacillus culture will greatly decimate the adult-egg-larva cycle of mites, gnats, et al.



  17. Jak,
    If you sprinkle diatomateous earth on the top of the soil they will all die, so will their young from eggs when they hatch. It will kill any hard bodies creatures as they breath thru their shell, and the DE fill up the holes and they stop respirating... works great on fleas if you have animals and get hit hard in the summer. It's non-toxic, easy to work with, has calcuim and silica in it, and can added in most any amount to a plant without issue.

  18. Snap, just caught your post. I use this too, it's great!
  19. yeah, i really like the results.

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