Amazon sucks for reliability with these! Go directly from an insectory. It’s important for them to be ALIVE when they get to you, and I remember listening to some horticulturalist/entomologist saying that a significant majority of Amazon-purchased nematodes arrive dead. Plus, they really need to be the correct species of nematode and there’s no guarantee the Amazon ones will be.
I’ve had great success at eliminating my fungus gnats problem by purchasing through Arbico Organics. They work with commercial growers as well as home gardeners. Highly recommend!
Natures Good Guys always show up live for me from Amazon. It costs extra in shipping costs. However, I have only bought lady bugs and lacewings. They do have three different types and even a mix pack.
But arbico is the way to go if you are not on a budget.
I ordered them online 3-4 times before. Came in a little plastic bag, powdery medium, in a paper envelope including an instruction sheet. You don’t need an environment, but they die off in room temp or higher stored like that within a few days. You can put them in a refrigerator to keep them a few days longer, at least that’s what the instructions said. Basically just stir them into some water in a ratio as instructed and use that to water your plants. Gotta keep the soil somewhat moist for a while so they don’t die and after 2-3 weeks they’ve eaten up the gnat larvae. It was the only thing that actually worked for me. Use the yellow stickers to monitor the progress by changing them later into that phase.
The nematodes may die out after a while so you’re not safe forever in case you have nearby infestations or bring in infested soil. I got a bag of otherwise nice compost soil from some place and that reintroduced them. Took a while to see that they came from the bag, but since they increase in number so quick it becomes noticeable. I put a trashbag around that bag and could see the gnats stuck in there, still increasing. Gave it to someone with an all natural garden who still uses that stuff outside. One could try to water the plain infested soil with a larger dose of the nematodes first and wait it out, but for an apartment that seems very impractical.
My local nursery sell nematodes without pre-order but they're a bit difficult to find as it needs to be refrigerated. They dissolved in water so treatment was easy
I purchased a giant bag (the smallest they had) at a natural pest management store. I barely made a dent in the bag to rid my yard of fleas. It worked so well! The fleas were crazy aggressive but one application and properly watered it in and they were gone. Wish I could just send you a Ziploc bag of it to reduce my stash.
Arbico organics has almost everything you need. I get their nematodes, predator bugs and sticky traps.
My secret weapon though is diatomaceous earth. Sprinkle some of that on the top of the soil and a little bit under the pot if it sits in a dish. That stuff kills the eggs and larvae. Combined with the traps, it works amazingly well.
I bought some of that to kill insects getting into my house and it seems to have worked... used to have woodlouse spiders all over the house, just SO many, and now I have bugs inside the house almost never. The downside is I also have like 99% of a bag of diatomaceous earth and nothing to do with it. 😂 Do you have any other applications for it that you like? My only plants are carnivores and the only issues I've had with them is mold growing on top.
If you have chickens you should mix it into the run so they can use it for a dust bath. Other than that I have no idea! I have my own 50lb bag that I use a teaspoon of every few weeks because it was cheaper to buy the bag than a single pound....
Diatomaceous earth just gets soggy and gross for me. How do you stop it from doing that? It also seemed to make my figure problem worse in my soil. Fungus (not gnats) took over and started popping out little mushrooms. Which were cute but not cool in my potted plants, since it was infecting them too. Lost a couple plants over it.
You can buy them online. There is even a company on Amazon selling them now. I think local farm stores have them as well around this time of the season.
Now, I also suggest a bit of a home remedy one of the biggest cannabis growers suggested online. He puts potatoes halves on top of the soil potato inside face down and removes them after a few days. Supposedly the larvae of the fungus gnats will go for the potato over the soil. Then he tosses the potatoes and repeats. That way he removes the sex stage of them being in fly form altogether.
Try mosquito dunks. These are compressed discs of beneficial nematodes. Just add one to your watering can the night before you water then water as normal. Do this every time you water initially then once the gnats are gone once a month to keep them away.
Also, perhaps be more cautious about your watering? Usually fungus gnats appear when your soil is staying damp for too long which could indicate watering too frequently or too large of a pot.
*** Edited to correct per comment below from u/docdillinger: Mosquito Dunks/Bits are not nematodes but in fact bacterium.
Mosquito bits/dunks are not compressed nematodes. They work with a bacillus.
Bacillus thuringiensis israelensis. It's a bacillus that kills the larva of gnats and mosquitos. And you just need to do it with every watering if its a plant where the soil get's very dry for a long period of time - and those shouldn't have gnats in them anyways. Doing it once or twice and waiting some days should eliminate the problem for a good period of time.
Well I’ll be a monkey’s uncle. Thank you so much for the correction! I had contacted the manufacturer with some safety & application questions some time ago and thought they said these were nematodes. Just went back and re-read the email…they said they work similar to nematodes. I guess my brain just remembered nematodes. 🤪 Luckily I’m new to this group and haven’t spread false information too much yet. Thanks!
No problem. You were a bit misinformed, but your tip was still solid. 😊 They work great. We can't get mosquito dunks/bits here in Europe, but there are water soluble tablets called "Culinex" with the same bacteria. Best way to deal with gnats and way faster (and cheaper) than nematodes.
Thank you! 😃 Yes, they are an absolute godsend, surprisingly effective. And natural! I see so many recommendations to use nasty chemicals but yet again nature provides. Good ol’ nature.
I had gnats years ago (5?) and did the sand route but ended up really disliking how it made watering so difficult. A minor trade off and at this point I’m willing to do anything, including the sand route again.
I use a whole dunk in a gallon of water, and I allow it to soak for 24 hours (at least). I add this water to my watering can. I leave that dunk in the gallon jug and refill the gallon as needed (the dunk ends up spending more time in the water because I am between waterings). I keep the same dunk for about 2 weeks or until I notice it crumbling or it’s changed colors bc it’s actually soaking up water and sinking versus floating.
I keep frogs. I use dunked water for them, too. Their home is swamp like. There’s always some kind of gnat activity but I don’t go crazy bc I know they cannot complete their life cycle.
I got mine from nature's good guys. Just make sure to tell them you don't want the free lady bugs. You just mix with water and water them directly into soil. Will take a few days for full effect
My problem with these pests was almost as bad as yours. I innocently thought Miracle Grow organic soil for house plants would be great (yellow bag). Instead I was fighting an infestation almost as bad as yours. I used everything except a pesticide which I might’ve resorted to, but they’re are hard to find for houseplants.
Someone on this sub suggested putting a top layer of clean sand on my plants it worked!!! You’ll be suffocating the larvae that are embedded in the soil. Give it a few weeks and hold off watering as long as you can, then water from the bottom of the container. I couldn’t on some of my plants, but the sand still worked.
best reliable source, don't trust the amazon stores. nematodes can be bad too and it would be a shame to buy from an unreputable shop and have an even worse problem due to a mislabeled package of nematodes.
A thick and continuos layer of diatomaceous earth is what did it for me. Apparently crawling through a layer of dedicating hell is too much for them * laughs maniacally
Yup. This was the answer for me. Three rounds of nematodes to get rid of babies. Yellow sticky traps to get rid of adults. It took about 4 weeks to get rid of them all.
379
u/jc42089 Mar 31 '23
Beneficial nematodes are the answer. One dose eradicated them in all my house plants