Fungus Gnats – How To Get Rid of Them

Fungus gnats!? Grow Room Threat: Orange!
Small, pesty flies, two or three millimeters long, like many mosquitoes,
but they don’t bite, or sting. No, instead they love to crawl and creep around on
plants and growing media! They fly around stupidly, getting in your face, buzzing
from place to place, slowly and seemingly without purpose, but somehow very
irritating at the same time– kind of like my father-in-law on Facebook! Some
growers confuse them with winged root aphids, which are better fliers, with a
rounder broader body, and are more attracted to your grow lights. Sure, the
adult gnats, themselves, don’t do any damage, but they love to fly into my
eyes, and up my freaking nose, and seem to have a sixth sense of when I have
both my hands full and I can’t swat at them, but okay. It’s their larvae– hatched
from tiny eggs laid by the female adults in moist growing media– that cause all
the issues, especially to young plants. The fungus gnat larvae primarily feed on
organic material, algae, and soil fungus, but in increasing numbers, that
necessitates a broader diet, including roots, and plant stem tissue. Yes, they
nibble on your plants’ roots, people! This in turn creates wounds, which open up the
gateway to secondary infections from the likes of Pythium, Phytophthora, and
Fusarium. Seedlings and younger plants can die! Older plants could stop growing!
Leaves will discolor and wilt, and nutrient and water uptake will slow! It’s– enough
talking already. Let’s go neutralize some gnats. As with
all pests, you must first understand their lifecycle, and disrupt it,
preferably, at multiple stages at once. Ignored fungus gnats will breed
uncontrollably, and a few weeks after spotting a handful of gnats, you’ll have
a major infestation on your hands. Fungus gnats can hitch a ride into your grow
room on your clothes, or cuttings accepted from friends, through gaps
between doors and walls, in soil, compost, and soilless potting mixes. Once
introduced, they seek out moisture and humidity. Top feeding your plants too
often creates ideal breeding conditions, that is, moist surface growing media.
Consider irrigating your pots from below, and allowing your plants to wick up
moisture instead. At the very least, ease off with irrigations, and let your
growing media dry out more between waterings. Now, adult fungus gnats enjoy a
brief moment of sexy time together and then the females lay their eggs in your
growing media– sometimes also in the algae that forms at the top of stonewool blocks. Try using block covers, or fashion some
yourself with little squares of correx, or plastic sheeting to stop the algae from
forming in the first place, and to form a physical barrier against the gnats.
Okay, now that we know our enemy better, how do we kill them? I recommend a
two-pronged approach, my friends. Target adults with foliar sprays and traps, and
larvae with nematodes, mites, or biological larvicides. Now, you should
always have some yellow sticky traps in your store cupboard– even better: already
in your garden. Sticky yellow traps are a handy monitor for pests, not just a
reactive measure. Peel the protective wrapper from both sides, and lay them on
the tops of your pots, like this, rather than hanging in the air, so they catch
emerging adults. Next, call your local grow store, and ask them if they have
any predatory insects in stock. Do this right now because chances are they may
have to order them which can take a few days. For the adults, try something like
Azamax, a botanical insecticide. miticide, and nematicide. Use a foliar spray for
a few days before sending in any beneficial insects. Make up a medium
strength solution: one fluid ounce per gallon, and foliar apply immediately. Work
fast, wear a respirator mask, and get the hell out of there. Just like the zombie
apocalypse, my friends. As for killing the babies, if you have cuttings or
seedlings in blocks, you can dip them into a bacterial larvacide containing
Bacillus thuringiensis Israelensis, or BTI, such as Gnatrol WDG or Mosquito Dunks. Woo! Sorry, got a little carried away. Remember, if using multiple combat
methods, it’s important to know that they’re fully compatible with one
another, as some pesticide products will kill your predators. Also, ask your grow
store for advice on specific product combinations. Parasitizing nematodes are
incredibly effective against fungus gnat larvae, and can decimate fungus gnat
numbers in days, while causing no harm whatsoever to your plants. The nematode
species of choice for this application is: Steinernema feltiae.
You can buy them in little packets. It looks like dust, but lurking within are
millions of tiny little beneficial nematodes. Note the use-by date on the
packet. The nematode enters the body openings in many types of soil larvae
and uses them to breed– killing the larvae in the process. Excellent! Fill a watering can with dechlorinated water, and then add the nematodes, and
stir; apply carefully and evenly to the surface of your growing media. I redirect
the drain pipe of my ebb and flow table to catch the runoff so I can reapply to
other plants. They won’t survive long sat in water so use it up right away. Hypoaspis miles: a tiny, predatory mite, invisible to the
naked eye, has recently been reclassified with an even catchier name– Stratiolaelaps scimitus. Many growers deploy these mites is a preventative measure as
they can last up to 70 days without food, so why not just let them hang out, just
in case. Usually they come prepackaged in sachets or tubes of peat and vermiculite.
A 34 oz container of Stratiolaelaps scimitus retails for around 40 dollars, and can treat
between 100 and 200 3 gallon pots, so it’s not going to break the bank.
Sprinkle it onto the surface of your growing media, and you’re done. If you
can’t get ahold of predatory mites, then try a top dressing with diatomaceous
earth, Growstone Gnat Nix or Gnat Block by Flying Skull. I use DiaHydro, which is
fairly chunky. Try to get the most powdery stuff at the bottom of the bag.
Diatomaceous earth is fine for us to handle, but to a newly-born gnat it’s like
crawling over a razor wire. It’s only really effective when dry so try not to
get it wet. Once again, flooding from the bottom is
the preferred method of feeding. Some growers use neem cake in their soil mix,
or neem seed meal as both a soil enricher, and a preventive measure against
fungus gnats. If you’re growing in NFT grow tanks, then be aware that capillary
matting is also a favorite for fungus gnats, so be sure to secure the tank
covers well to avoid gaps. Finally, don’t forget to secure your air inputs with
intake filters or bug screens, and always keep your grow room clean and tidy. If
you’ve been gardening outdoors, take a shower, and change your clothes, and
footwear before entering your indoor garden. Thanks for watching, and don’t
forget: if you have methods of fungus gnat control, or techniques for complete
annihilation that I’ve failed to mention, then please don’t forget to share them
with us in the comments below. Sometimes battles with fungus gnats can
last for months, even years, but don’t lose heart, just stay on top of it.
Remember to always read the label, and take proper precautions when using any
pesticide products, especially indoors, my friends. Hit that subscribe button, you
know you want to, and it’s free and easy, just like a pair of frisky fungus gnats
having a last Tango in midair before meeting their inevitable demise. Life is
so short, amigos, and on that note, I’ll bid you farewell until next time. Adios!

100 thoughts on “Fungus Gnats – How To Get Rid of Them

  1. Thanks Everest! How do you feel about H202 in coco if you do not plan on building a beneficial microbial zone on purpose (more sterile like DWC?
    I had them for years in the home, just as a matter of locale so when I started to grow it was a fast problem. I tried Apple cider vinegar traps, dish soap traps, nothing worked until I found Mosquito Bits (same as dunks it's a BTI product -please read as I would like to know others opinion on the safety of this product
    I am looking for something as effective that I can be sure is safe to eat the end product.

    Here is what I did:
    Using this directly on top of my soil and watered through, added sticky traps for adults and they were gone in a week.
    So I went around the house adding Mosquito bits to coffee mugs with water along with sticky traps putting them above little lights that are on at night with the cups nearby.
    They love to breed in cups full of Mosquito Bits and water. It's like a magnet and they seem to ALL go there to party and lay eggs. Totally disrupts the cycle.
    Gone gone.
    put a fork in it.
    The controversy starts with this on the label:
    With the Mosquito bits it says there is BTI Strain 144 and "insecticidal toxins"

    A 40 year agricultural grower and I had a discussion about this as I was raving to others about the product and he said he personally wouldn't eat anything grown with it. 🙁 that stinks too because I finally won the war against the gnats….

    If anyone thinks this safe or know of folks that use this on edible plants I would like to know your opinion the MSDS chart on this isn't complete so it's not a help.

    I like the Azomax idea but these are still babies.

  2. Fly tape, Bowl of apple cider vinegar with drop of dawn, and diatomaceous earth… problem solved GG and if you are going to spray, spray the soil that is were they live, not the leaves lol.

  3. All you will ever need!  3 drops per 55 gallons so it goes a long way as well!!Microbe-Lift® BMC kills developing mosquitoes before they become breeding, biting adults. It is a liquid product, so it has no adverse effect on the aesthetics of ponds and water features. Microbe-Lift® BMC can be applied to areas that can contain aquatic life, fish and plants. It can also be applied to areas used by or in contact with humans, animals, horses, livestock, pets, birds or wildlife. 2 oz treats 400 gallons for 2 years. 6 oz treats 2,000 gallons for 16 months.

  4. My wife loves plants and had them all over our apartment. But one of them must have been infected. We didn't notice for a while, and the next thing we knew, our entire apartment was FULL of gnats. When I would look into the pots for her money trees, you could see the young flies crawling through the soil, and burrowing through it. There were so many. And that was just ONE plant. We tried soaks, covers, traps, soil replacements, etc. The infestation in our apartment was just so severe that we had no choice but to do the nuclear option and get rid of the plants.

  5. I got this tip from the Grow Your Own video ( and it works better than anything I have tried.  The name of the product is Microbe Life Biological Mosquito Control.  Not a single gnat after I started using this in my reservoir.  I follow his protocol of 3 times the dosage recommended for mosquitoes.  It's cheap also and the bottle I got will last me forever.

  6. Thanks so much, I have to say I was extremely stressed out when I sat down to search. I love the enthusiasm from this guy. Subscribed! #growsomething #10beeinc#staylocal

  7. In the spring, when starting seedlings for a garden, you'll always end up with a few fungus gnats. I love my sundews (predatory plants) for this reason. Set a few sundews up in the grow area in a painted 3" mason jar in a rockwool kratky hydroponic setup (with no nutrients, only distilled water) and it'll take care of a 'very slight' infestation of fungus gnats.

  8. It's very hard to hear your videos. A sound enhancer may help us hearing impaired folks…Besides that, great info!!

  9. Use perlite or pumice rock place it on top of the soil!! Put about an inch or two to stop the gnats!! This is their eviction notice!!!

  10. Also sm90 is a really great product!!! And also I heard you can use hydrogen peroxide mixed with water! But must be mixed properly. Ask your friend google for directions

  11. Our house has so many gnats, we bought sticky gnat traps and if you put them in every room, they decrease a lot.

  12. i use double sided tape and string it around the cieling area, it has lots and lots of gnats dead on it, but they still live in the soil!
    even though ive sprayed many times with Resolva insecticide.

  13. Why not just plant cilantro and other companion plants that repel pests like fungus gnats in particular?

  14. My houseplant has fungus gnats and I pulled the plant out of its pot (with dirt still connected) and all hell broke loose

  15. total fucked-up video…. hey man, stopp taking speed and try weed instead 😀 Slow down buddy, it's not good for your heart and lungs, seams like you are almost out of air in your lungs, and your heart starts to beat harder each video you make… take it easy on yourself man, or stop doing videos 😀 hahahah…. see you at cardiology unit

  16. What about 100% Neem oil?
    I've heard good things, so that is what i'm using now I've seen 2 insects that I believe may have been fungus gnats on my plants.

  17. I have the problem with my worm bin. Does anyone know if BT is safe to use with red wrigglers? I’d also like to know if I can use the mosquito baits in my worm bin and not hurt the red wrigglers?

  18. 1 part hydrogen peroxide to 3 parts water will kill all the fungus knat larvae in the soil! It will completely kill them and the eggs!

  19. As a lover of latin and the binomial nomenclature, ( which is often incompassing Greek origins as well as Latin and also Anglified additions often peoples names ), I have to correct the pronunciation in this vid of Steinernema feltiae. It is pronounced Stine-err-neem-uh felt-ee- eye. In Latin ae is taken together always, and is pronounced I ( like Eye ), the I however in Latin (just to confuse everyone ) is always pronounced in its short form I ( like "in" or "it"). Stratiolaelaps scimitus is pronounced Strar-tee-ole-eye-laps skim-it-uss. ( uss as in Puss, as in a feline ). Great vid, hope this helps.


  21. I’m so sick of these lil f’er’s here’s my story. Too mad to tell it right now. Most pathetic venting ever. I sorry.

  22. I know this video has to do with fungus gnats affecting plants, but what about the human body? Can these things infect you with fungus? I got attacked by those little no see um gnats during a trip to South Florida, they tore up my legs, and I had like a couple dozen bites on me from them. And then two months later I got very ill, it started out with a horrible stomach infection and pain, and then, this is so embarrassing to talk about, but this disgusting fungus stuff started coming out of my skin, and I'm still dealing with it. This has been going on for months now, it's disgusting, it's driving me insane, no doctor can give me any answers about it yet, and it's affecting my quality of life. I've tried everything to get rid of the stuff, but it just won't go away! I've been wondering if the bugs may have caused it, especially after hearing they are associated with fungus.

  23. The only thing more annoying than gnats is this guys’s maniacal voice and delivery. Jesus. Lay off the caffeine or cocaine.

  24. If you need to wear a mask when using chemical insecticide on a plant you intend to consume, you should not be using that insecticide.

  25. I haven't had fungus gnats in year's using taller pots and bottom watering when plants are young with top watering once a week and as the plant gets rootbound I top water every time.

  26. I use landscaping pebbles about 1/2 cm in size average, and have never had issues since. and they are about 2-3 cm deep. this allows air to reach the medium but repels the gnats as the stones dry out much faster then the surface medium underneath. it also has the advantage that you tend to retain more moisture in the medium for longer. and it looks aesthetically pleasing.

  27. I cannot get rid of this. Do you think repotting my monstera and washing the roots before putting into new soil might help?

  28. Ooook… Not quite sure on what just happened but I have gnats does anybody know how to get rid of them…?

  29. Bruh , relax sometimes ,
    I'm not getting the info
    Uve got much
    I get how that's uniquley u , I guess it's better than subtitles
    Just sounds like a tweakers//heavy sativa tweakin , already stressed n trying to understand what the hell your saying :/ I've got 30% n I'm not going back n replaying for much I'd rather play at .75 speed
    Nevertheless, really thank you, been watching some your vids here n there

  30. The nematodes work best in my experience.all the gnat control formulas are shit and very rarely work unless you use really strong pesticides but you don't wanna be using that shit on edible crops (or smokeable ones) especially if you,v went out your way to grow organically.
    Nematodes are cheap, safe to use ,don't harm your crops or your organic methods and are very effective wen used in conjunction with some sticky yellow traps for the fliers.

  31. When this happens to me I hoover the top layer of soil out the pot and water with gnat off soon exterminates them

  32. 1 part peroxide to 4 parts water applied to the soil is the cheapest most effective way I've used to kill the larva and eggs. Diatomaceous earth is messy and useless unless you irrigate. Never noticed Neem oil to deter anything. azamax works but not as well for the price. It does kill a lot of other bad insects so it's not a bad purchase

  33. Were you hitting the Meth/Crack Pipe before you made this Vid lol ? Speaking a Mile a Minute I couldn't keep up with ya.

  34. When you are talking like a fool it is very hard to understand. And I do have problems with my plants and fungus gnats, but I can’t take you serious.

  35. and you can get rid of these nats right now for a low price of 19.99 and if you call now theres more!!

  36. But HEY That's just a theory… A GAME THEORY – Wrong channel xD
    A Plant Theory! Thanks for Watching! 😛

    Seriously, are you MatPat's brother? You both sound very similar with your energy levels hitting extreme levels!
    Now I just wish you two would meet and make a theory together XD Best CrossOver waiting to happen!

  37. I have a serious question, I have three plants indoor in a green house tent in my room with window and door tight with air filter.. And I have bug's on my plant, where do this fucken bug's come from?? Do they form and born from coming from the soil?

  38. One day i was on the iowa river with my dad and we went into a half sunken forest and we ran into yellow gnats

  39. nicotine in water in various concentrations 1 cigar to 1 liter and from there 2 cigars and then 3 (let it stay overnight in shadow and the strain the tabaco) depending on the resilience of the pests

    apply daily and also always spray the medium and the sides of the pots and around the pots even the runoff dish can be sprayed spray the shit out of everything if you have to 😀

    also may be mix in 1-2 ml of dish soap and 3-5 ml of cooking oil

    if this 3 things combined dont kill them they will surely slow them down (try just the nicotine water first)

    and if you still have a problem the you can research natural pesticides to see what fits your needs

  40. In Minnesota, I buy soil in the winter and let it sit outside when we have cold spells -20 for a week works every time to prevent them.

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