100% solution to Fungus Gnats?

so i just got done with my first organic grow ever....

fucking nightmare.

i wanted to go 100% organic for my first grow and i decided to go with MSM for my soil and watered with calmag RO water.

about 1-2 weeks into flower...i saw a few small gnats. i did a search and found out that they were fungus gnats and i started reading all the options of getting rid of these fuckers. problem is most of the ways to treat them is not organic and so since i didn't want to "taint" my first organic grow i decided against using chemicals and did the whole "dry out the soil" trick.

didn't work, they just got worse and worse. luckily my cab is completely enclosed...but around harvest time i had absolute shit yields, crappy roots, and a swarm of these annoying motherfucking gnats. the last two weeks i maybe opened my cab 2 times because i would get so fucking annoyed every time i open my cab only to see like 30+ gnats flying around inside.

even then...i sorta just ignored the gnats and harvest....i figure...what the hell, i'm going to have a crappy yield but at least is 100% organic. while trimming i had to spend probably 2+ hours picking these stupid fucking nasty gnats off the nugs.

i'm now thoroughly disgusted with these stupid gnats, organics, and fucking SOIL in general. i've come to the conclusion that soil is disgusting and since organic soil is nothing but animal shit...its super disgusting and pest infested.

i'm at the point of just leaving SOIL in general forever. but, i still have like 60-70lb+ of MSM soil sitting in my shed. its probably infested with gnats crawling all over bat shit by now...but whatever..

should i just throw out all the soil or is there some way i can do another round with the soil? i refuse to deal with these fucking gnats another round. i am willing to do whatever to kill these things, i will pour a gallon of acid over my soil if it will kill the gnats - screw organic this time...every last gnat must die.

FUCK FUNGUS GNATS. i'm beginning to think chemicals are out there for a reason.

Just for your two cents, hydro mediums can hold fungas gnats as well as soil mediums. And another note, I use chemical ferts and have a shitload of gnats but I know how to control the population with sticky strips and gnatrol so it works for me. Organics not what gave you your gnats. They might like to stick around with organics, but they do so with chems too.

beneficial nematodes - 100% success.

Gnatrol, mosquito dunks, etc.... anything with Bti in it will also work and these are 100% safe and organic.

To prevent in the future, find a way to keep the top inch or so of medium dry. Fungus gnat larvae need moist media to live in.

HeadyPete said:

beneficial nematodes - 100% success.

Gnatrol, mosquito dunks, etc.... anything with Bti in it will also work and these are 100% safe and organic.

To prevent in the future, find a way to keep the top inch or so of medium dry. Fungus gnat larvae need moist media to live in.

Click to expand...

Nailed it. If you have a fungas gnat problem already, and you use mosquito dunks, youll just have to wait until the adults die, which may take ~2 weeks. It's best you also cover the top of the medium with sand and/or perlite to keep them out of the medium.

Fungas gnats= OVER WATERING imo

I used to always be guaranteed a batch of fungus gnats... now i have a slow release organic fert with neem cake mixed in. Since using this i have ZERO problems with gnats. I always use compost and that from outdoors and bring it in too.

Before i discovered neem i had a spray bottle of pythrum (organic) that i sprayed whilst watering as they all rise to surface... this will keep the numbers down and keep em out yer buds.

Diamatecous earth works well too...

Dont give up on the organics!!! Get yerself some coco!!!

Good luck.

An effective method would probably need to be applied once a week for three weeks to interrupt the cycle.



Namaste, mess

Gnats loved my Rockwool E&F (no organics) They're largely oblivious to my DWC. It's the moisture they love. I used to vacuum them out of the grow.

Nematodes are really the best solution. Not only do they seek and destroy all gnat larvae in your media, the will consume 100s of other pests, pathogens, fungi, etc all while gently avoiding damaging even the finest root hairs. They will live and reproduce as long as the media is moist and there is prey for them to consume. They are also very hardy and resistant to fertilizers and most chemicals.

Air flow, Air flow, AIR FLOW. Check my gallery, take a bungy-cord-o-fans, add them to the inside of your cab so the air-flow hits the top of the soil (and the gnats), gnats might last about a day or two depending on air-flow.

Top-dress when watering, don't water till they disappear, let the soil dry out for the top 20% of the pot, stick your finger in don't water until it feels DRY. Top-dressing after drying-out will smoother the eggs, dry-ing out kills the parents.

I get pretty dank with my teas and topdressing (like stinky, sticky mud) and always have a few gnats (nature is like that). I feel companion planting comes into play here. My last few grows I've been companion planting a shade/ornamental fescue grass (Red Fescue) with my babies. The areas with the fescue seem to have no gnats. Companion planting seems to have a synergistic effect rather than a competitive affect, if container is big enough.

Infestation of Gnats=something went wrong (over-watering/air-flow combo?), IMO there is no need for any chems when it comes to gnats. Controling the enviroment is all I've ever needed.

Put some sand on the top of you media, or get some fly strips, and coil them around the top of the bucket. Let everything get good an dry, without having your girls wilt.

Your giving up to quickly, if your kid had lice would you blame in on the organic veggies he/she had been eating?

I've seen and dealt with bug problems of all kinds, chems dont make anything easier, in fact, they just fuck with the nervous system of plants and people alike, take your time, figure out why the bugs like the environment they are in, like stated above, overwatering is probably the best thing for keeping gnats around, here's an easy solution, try mixing up some soapy water with dish soap in a spray bottle, spray it on the top of the soil, that's where they breed and the larvae feed on roots, the sudsy mix chokes them as they eat, and soap will not harm your plant, a few waterings later its all gone, plus some people use dish soap as a wetting agent.

Tobacco tea. I have a tropical outdoor and my potted plants used to be heavily infested by many kinds of nasty bugs, including fungus gnats. I found a recipe of tobacco tea (there are many in the net) and sprayed my plants, and the bugs never came back. Also, I poured some dissolved tea in the pot and I have no gnats anymore. Use it every 15-20 days. Of course, you should not spray your plants in blooming

(EDIT sorry CSTV I did not see your post)


NO NO NO!!!!!!!!

Not to step on anyones toes here but I have the cheepest and quickest way to get rid of fungus gnats.
I spent close to $100.00 buxs and nothing

just go to the hardware store and get sand any sand wil do or just go to the beach
and get it there.
Put 1/4 inch of sand on top of the soil and they will be gone Guaranteed in a week.

Beleve me I had them and I had them bad,
also I might add 1 yellow no pest strip to get the rest of the flying buggers.



Stay safe and high.
.........HYDRO.......

Careful with tobacco treatments as they can spread tobacco mosaic virus to marijuana.

screw the top dressing of perlite/sand, screw letting your medium super dry out in between waterings (this does NOT work at all), and screw everything else. these things are annoying as hell and just will not go away.

I just went and bought a pack of beneficial nematodes for $19.99. as far as I can tell from what I've read this means problem solved. save all yourselves the hassle and if you see the sign of a fungus gnat infection (if you see one there is many, many more to come, believe me) just go ahead and buy a pack (you can get nematodes on AMAZON for christs sake). i've been dealing with them since they infected my main batch of soil and they will not go away. I've should have just bought the nematodes a long time ago instead of using methods that may or may not work.

just FYI i've had a 2 gallon grow bag filled with infected soil that I have used for experimenting purposes. it was placed away from everything in an isolated area about 3 weeks ago. it has not seen water in probably 4-5 weeks (no plant in it just dirt). it also has a layer of dry perlite on the top of it. I dug up the soil some just the other day just to see whats up and I'll be damned if there aren't gnats coming out of the middle of it. not many but they are still there. that should give you an idea how well the whole "let your medium dry out/use perlite on top" strategy works.

just ordered some beneficial nematodes,ill also be getting the yellow sticky strips to get the ones alreadys flying, my problem isnt soo bad yet, ive seen only 2 or 3 of them, but not trying to get anymore, im also in my 5th week 12/12, just wondering how fast till it will start to help? Will they take away nutes from my guano tea?

I had them somewhat under control when I used them but the gnats were gone within 3 days. the nematodes also annihilated any sign of gnats in my main batch of soil. by far the best $19.99 i've spent in a while my problem is finally solved. and no, they will not effect anything in your grow besides eating the nasties and anything associated with them. I love beneficial nematodes! I'll probably buy another set to deal with the fleas in the yard when spring rolls around.

so in my experience beneficial nematodes work extremely well and have been the only permanent solution to gnats so far.

Gnatrol is all you need, this place has it for cheap:

http://www.ghorganics.com/

Highly recommended. Every organic soil mix I've ever used was sporting some fungus gnats within a week of planting & watering.

I used a low dose of Gnatrol (2 tsp/gal) when I transplant, usually that is all that's needed to permanently kick their ass. If you see any afterward, add some more every 1-2 weeks until they're gone.

Nematodes work very well too. Fungus gnats are very annoying but these two 100% organic solutions make it easy to completely beat them. Much easier to wipe them out than spider mites.

freeradical said:

Nailed it. If you have a fungas gnat problem already, and you use mosquito dunks, youll just have to wait until the adults die, which may take ~2 weeks. It's best you also cover the top of the medium with sand and/or perlite to keep them out of the medium.

Click to expand...

my theory is that if i just made a gallon of consentrated mosquito dunk-water , then flitered threw a kitchen seive -or use gnatrole the proper way, both get deluted only one has proper measuring- i can soak all of my pots most importantly the small/younger most vulnerable plants then the pots have been enoculated from the gnat ever succesfully reproducing 'in that pot' for quite some time.

my theory is that a bti treatment enoculats the soil and oasis cube, rockwool whatever medium you clone in aswell. ive have 20 clones go to shit and start from scratch cause fungus gnat adults got under the humidity dome and the larvea literally would eat/bore tunnles around the outside 'skin' of the soft cuttings, they become softer as they want to push roots -well the larvea eat the roots befor they could set and while their trying to form.

the website repotme.com had some granular form of gnatrol that had 2 years or twice the shelf life of the original liquid form, i contacted them and they no longer cary it. i have found atleast one site that says the original liquid has been discontinued by the manufacturer, originally i ordered the liquid gnatrole and had got refunded.

another waky theory i buit up is that as you dry the soil out and inturn dry the larvea out, they will be more attracted to the main-big roots that naturally hold more moisture. this is from what ive seen in oasis cubes, how they slithered up and down the cutting and fed off it.

something els has colinized my dirt now, little tiny mite looking things, they look just like the fungus gnat preditors. let me know if theas can become a nusance in absance of fungus gnats, if they unturn eat the plant and over-colinize in extreamly organic media???

Edit; ill get an order of nematodes and continue on that rout, thanks dirkdaddy. any hint as to what breed you chose that worked soo well? thay should get rid of the fungus gnat preditors too id imagen. i found out that broad spectrum pesticids are toxic to nematodes so try them befor trying pyrethrins or even insect soap

-gnatrole is also avalible @ bghyrdo.com, a 32oz for like 22.95. i just called to conferm cause other shops havent updated their sites, no longer cary it and dont update information. -thank you bghydro