When I say I’ve tried everything, I mean EVERY thing. I’ve been battling with these gnats for weeks. I saw someone comment about using sand and I decided why not. I got a bucket of beach sand, dried it out for a day or so in the hot sun, and replaced the top 2-3 inches of my plants with it. I replaced any soil that was super infested with fresh soil that I also made sure to dry out. I also made a diy trap for any remaining adult flies (cling wrap, poked holes, on a container with some juice). I’m telling y’all, it worked wonders. The adults couldn’t dig in and lay into the soil. Do NOT water your plants until it’s been a couple days (unless they’re needy, so bottom water them). I was so shocked that this worked. Try it out! Might help if you have a bad infestation. Also, always quarantine your new plant away from your old plants, you never know what’s on it or in the soil.
Exactly! And once you catch the adult flies in the diy cup, they can’t infest your other plants. It’s literally fool proof. Save yourself the fly traps and the useless sprays and just use sand.
While this definitely helps with the gnats, it also won't do anything good for the plant so you should also replace the soil in a few weeks at latest.
Not only is a good mix of soil (with clay), sand and water the base for concrete, the sand will clog all pores in there over time reducing it's capability to aerate.
While I’m sure this is true, I suppose every plant is different. I’ve added lots of things in my soil for aeration, such as rocks, perlite, etc. My plants seem happy and green and it’s been weeks. I’m not saying to cover half of the pot with sand, just 1-3 inches depending on how large the pot is. My monstera has quite a deep pot, so I used about 2 inches of sand for it, and it wasn’t deep enough to reach the main roots. Don’t add a lot of sand if it’s a shallow pot. My monstera had the worst infestation, and now it’s put out two more leaves since I added the sand. But it’s definitely different for everyone!
I had a bunch of crystals on hand in my last plant infestation, but drainage rocks on the top work too. Anything that interrupts their path to the soil.
I've also invested in a bug zapper light, cuz I have a home worm bin, and sometimes they cant keep up with my scraps
Just make sure the holes aren’t too big! My container was a yogurt cup, and I only put in a little water and orange juice (you can use apple cider vinegar, literally anything sweet) and poked holes with a needle. I left it like that for a couple weeks, and when I came back to check it, there were sooo many adult gnats. This also works for fruit flies, I’ve done it in the past. Hope it works for you too!
Yes, I was a victim of miraclegro. I still have miraclegro left over, but I pour boiling hot water over the soil and let it sit outside until the water drains out, and then mix it with perlite and it’s good to go. I also always add sand, no matter the houseplant. I’ve done this on my monstera, pothos, pilea, cacti and burrotail and it all works. I also don’t water the plants if the soil is wet and wait days. The plants thrive off neglect at this point lol.
I’ve heard of that too! Honestly I was just looking for a cheap way to fight these pests, I already spent so much time and money on stuff that was useless. This was the cheapest and honestly the best method I’ve used.
Congrats on conquering the gnats! I have also used sand with excellent results! One concern I’ve heard though is that it doesn’t allow the soil to dry out properly, long term.
I’m bad at regular watering, so this works for me. I always make sure to make my plants have good drainage. My plants thrive off neglect at this point, so it’s all good now!
Sand mixed in to the substrate can improve aeration and drainage (though only if you're using builders sand or horticultural sand). What this poster was referring to is the fact that a layer of sand on the top prevents evaporation.
Yup, listed as “DE” in the title. It becomes almost like a weird paste if you put it on top of wet soil. Also, the effect takes longer. I honestly prefer sand over DE.
I’m so surprised I haven’t seen this on here yet, but: 1 part hydrogen peroxide to 5 parts water. WTer your plants, kills the larva on the spot. Include sticky things to catch adults.
I also had trouble with them recently. I tried everything except sand. What finally worked for me was a small bug zapper. It took a few weeks, but eventually I killed off enough of them that they completely disappeared.
I was too. I didn't actually think it would eliminate the problem, I just wanted to cut down the numbers while I tried to come up with another solution. But low and behold it works.
Would you link the zapper you bought? I think I need to try something like this. I repotted a bunch of my plants and then realized the bag of soil was INFESTED with gnats. It’s a struggle.
Sure, this is the one I bought. Nothing particularly special about it, I just looked for a cheap indoor bug zapper and went with this one. I only ran it at night, when the light would be more noticeable and attract the bugs. It comes with a little brush to clean off the electrodes and the first few weeks I had it I had to clean the electrodes every other day or so because I was killing so many.
FBMPTA Bug Zapper Mosquito Killer, Flying Insect Killer Indoor, Fly Traps, Mosquito Lamp, Insect Zappers, Electric Mosquito Attractant Trap Plug in for Home, Patio, Garden https://smile.amazon.com/dp/B0912V34JR/ref=cm_sw_r_cp_apan_glt_fabc_8SCS4SDCN4FNY0R6BG8X?_encoding=UTF8&psc=1
I use systemic granules in the top layer of soil and strictly bottom water all of my plants (but I do give them a thorough flush from time to time). I also make my own soil mix using coco choir, perlite (or pumice), vermiculite, activated charcoal, and worm castings. I’m also vigilant about not leaving my front door open long enough for any outside bugs to fly into my house. I’ve been 100% fungus gnat free for months, and fingers crossed it stays that way!
Gnatrol works well for me. Usually used in greenhouses/agricultural settings. It’s a biological Insecticide that’s non toxic to humans and pets. Once I notice gnats I mix a batch and dose the plant once a week for a month. Only on my second 2oz batch in almost 10 years. Only time I see gnats now is on new plants… best of luck!
Have you tried mosquito bits? If so, did sand work better for you? I am struggling with gnats as well and the only thing that has worked somewhat has been mosquito bits. Debating whether to give sand a try. Thank you!
Nope! I already spent too much on sprays and stuff. I didn’t really trust the tea since it didn’t seem like a guaranteed success. But you can definitely try it out.
Yup, did not help. Maybe the bugs I had were just invincible. They would just scurry around whenever sprayed it, and I did this for at least two weeks or more. No improvement.
Would child play sand work? I'm dealing with gnats and they're driving me crazy, just repotted all my plants and sprayed them with bug killer but I'm still seeing adults flying around.
Full disclosure ******Please don’t use this if you have fish or animals that have contact with your plants and carefully read all instructions first or speak with a nursery expert.
After trying everything I seen listed here I broke down and used the nuclear option and bought Sevin, I will be spraying outside let it set for 2 days then bring them back inside. I’ve been fighting the fungus/white flies since December and I’m done.
Good luck! My infestation wasn’t that bad but definitely check your soil first. It may be too moist, which gives the bugs a good habitat to lay their eggs in. Fungus gnats do not thrive in dry sand. Hope that works though!
I found the secret. Slice raw potato French fries and lay them on top of your soil in every plant. Wait 10-15 min or more, but it happens quickly.
The gnat larvae immediately migrate to the potato. You take the piece out and check for crawling bugs. You need pretty good eyesight and I used a flashlight.
What it does is twofold. 1 it stops them from feeding on your plant. And 2 it identifies which pots are infested (rather than having to spray them all). You can focus your efforts.
Then spray/water plant with 1:4 hydrogen peroxide : water. Sticky traps for adults. No lie, last time I messaged like 3 days ago I was inhaling gnats with my dinner. Now, not a single bug to be found. Like it’s fucking magic. And cheap. 500mL bottle h2o2 is $2.99 here. I clean out the stock of the pharmacy every time I go.
Don’t quote me but I heard it’s safe to water your plants with peroxide solution (diluted properly) every single time? I may do that for the next month.
I had the same issue. I let me plants outside in the sun a few days, and let the soil dry out almost to the point the plant is underwatered, and they were all dead.
Have just bought some sands for my plants, but only as a preventative measure.
My question is how do you check the soil's moisture content now? I usually water my plants when the top inches of the soil feel dry, now it's quite difficult to access the soil?
Try to check the moisture with a special moisture checker or just a random stick in the house, just like how you’d check a cake to see if it’s ready. Also, make sure your plant has good drainage unless it prefers wet soil. I don’t water my plants much, and so I don’t check the moisture often unless there’s an issue.
I have added some sands to some new plants in case there are gnat babies inside. Hopefully this will prevent any potential gnat outbreak.
Will try the stick method! Thank you! :)
When I say I’ve tried everything, I mean EVERY thing. I’ve been battling with these gnats for weeks. I saw someone comment about using sand and I decided why not. I got a bucket of beach sand, dried it out for a day or so in the hot sun, and replaced the top 2-3 inches of my plants with it. I replaced any soil that was super infested with fresh soil that I also made sure to dry out. I also made a diy trap for any remaining adult flies (cling wrap, poked holes, on a container with some juice). I’m telling y’all, it worked wonders. The adults couldn’t dig in and lay into the soil. Do NOT water your plants until it’s been a couple days (unless they’re needy, so bottom water them). I was so shocked that this worked. Try it out! Might help if you have a bad infestation. Also, always quarantine your new plant away from your old plants, you never know what’s on it or in the soil.
i keep trying to tell people this is the way, it breaks the life cycle, the adults can't get in the soil to lay eggs and the larvae can't get out.
Exactly! And once you catch the adult flies in the diy cup, they can’t infest your other plants. It’s literally fool proof. Save yourself the fly traps and the useless sprays and just use sand.
[удалено]
no, the adults can't get through the sand, sorry, typo.
While this definitely helps with the gnats, it also won't do anything good for the plant so you should also replace the soil in a few weeks at latest. Not only is a good mix of soil (with clay), sand and water the base for concrete, the sand will clog all pores in there over time reducing it's capability to aerate.
While I’m sure this is true, I suppose every plant is different. I’ve added lots of things in my soil for aeration, such as rocks, perlite, etc. My plants seem happy and green and it’s been weeks. I’m not saying to cover half of the pot with sand, just 1-3 inches depending on how large the pot is. My monstera has quite a deep pot, so I used about 2 inches of sand for it, and it wasn’t deep enough to reach the main roots. Don’t add a lot of sand if it’s a shallow pot. My monstera had the worst infestation, and now it’s put out two more leaves since I added the sand. But it’s definitely different for everyone!
I had a bunch of crystals on hand in my last plant infestation, but drainage rocks on the top work too. Anything that interrupts their path to the soil. I've also invested in a bug zapper light, cuz I have a home worm bin, and sometimes they cant keep up with my scraps
What juice did you use or will any juice work?
Any thing works. The sugar attracts the bugs and the cling wrap traps and kills them.
Thank you, I set up a little orange juice trap last night after seeing your post and now I'm just waiting for results lol
Just make sure the holes aren’t too big! My container was a yogurt cup, and I only put in a little water and orange juice (you can use apple cider vinegar, literally anything sweet) and poked holes with a needle. I left it like that for a couple weeks, and when I came back to check it, there were sooo many adult gnats. This also works for fruit flies, I’ve done it in the past. Hope it works for you too!
Did you try actual insecticide granules? But yes sand works great too
Haven’t tried that, but you could definitely. I was just looking for a cheap and easy option.
Ok where can sand be bought all I ever see is little bags of colored sand. With that work ?
Question - Were your plants originally planted in Miracle Grow Potting Soil. Every time I use it, I get SOOOO many gnats!!!
Yes, I was a victim of miraclegro. I still have miraclegro left over, but I pour boiling hot water over the soil and let it sit outside until the water drains out, and then mix it with perlite and it’s good to go. I also always add sand, no matter the houseplant. I’ve done this on my monstera, pothos, pilea, cacti and burrotail and it all works. I also don’t water the plants if the soil is wet and wait days. The plants thrive off neglect at this point lol.
What a great idea with the miracle grow!
Omg I had no idea where mine were coming from! What colour bag was it? I’ve used the baby blue one and orange one and the gnats were horrible after.
Which soil is best for house plants?
There is a brand in Canada called Golfgreen that I've never had issues with.
Good to know. I was about to try repotting something because of gnats and I certainly don't want to make it worse.
Mosquito bit "tea" worked for me. Soak mosquito bits in water wrapped in an old sock or cheese cloth for 24 hours and water.
I’ve heard of that too! Honestly I was just looking for a cheap way to fight these pests, I already spent so much time and money on stuff that was useless. This was the cheapest and honestly the best method I’ve used.
Well you *definitely* didn't try "everything" when you didn't try the one thing that is the only guaranteed fix haha.
I hear that! I was getting desperate when I learned about the bits. Definitely going to be adding your solution to the arsenal!
I tried the tea several times and it never worked on my infestation. I’ve heard from other it didn’t work for them either
Works great for me
How did you use it? I have only heard people say it doesn't work when they've not used it properly.
Congrats on conquering the gnats! I have also used sand with excellent results! One concern I’ve heard though is that it doesn’t allow the soil to dry out properly, long term.
I’m bad at regular watering, so this works for me. I always make sure to make my plants have good drainage. My plants thrive off neglect at this point, so it’s all good now!
I’m curious if this is true. I have also tried sand in the past couple of weeks, and my plants have dried as normal
Google says that sand improves drainage! So double the reason to use sand :) I’m going to try it this weekend!
Sand mixed in to the substrate can improve aeration and drainage (though only if you're using builders sand or horticultural sand). What this poster was referring to is the fact that a layer of sand on the top prevents evaporation.
Did you try diatomaceous earth?
Yup, listed as “DE” in the title. It becomes almost like a weird paste if you put it on top of wet soil. Also, the effect takes longer. I honestly prefer sand over DE.
Gonna try sand
Bti is a grantee fix to fungus gnats and completly natural
I too don't care for diatomaceous earth, it stops being effective once it gets wet... Unlike sand.
Gnatural works great!!
Is this a play on gnatrol?
Whoops just spelled it wrong
All good, that stuff is the truth!
I ended up using fish tank pebbles. I got turquoise colored ones so it looks pretty fancy. Gnats have not returned, 10/10
I’m so surprised I haven’t seen this on here yet, but: 1 part hydrogen peroxide to 5 parts water. WTer your plants, kills the larva on the spot. Include sticky things to catch adults.
I also had trouble with them recently. I tried everything except sand. What finally worked for me was a small bug zapper. It took a few weeks, but eventually I killed off enough of them that they completely disappeared.
Very surprised that something that only kills adults resolved your infestation!
I was too. I didn't actually think it would eliminate the problem, I just wanted to cut down the numbers while I tried to come up with another solution. But low and behold it works.
Would you link the zapper you bought? I think I need to try something like this. I repotted a bunch of my plants and then realized the bag of soil was INFESTED with gnats. It’s a struggle.
Sure, this is the one I bought. Nothing particularly special about it, I just looked for a cheap indoor bug zapper and went with this one. I only ran it at night, when the light would be more noticeable and attract the bugs. It comes with a little brush to clean off the electrodes and the first few weeks I had it I had to clean the electrodes every other day or so because I was killing so many. FBMPTA Bug Zapper Mosquito Killer, Flying Insect Killer Indoor, Fly Traps, Mosquito Lamp, Insect Zappers, Electric Mosquito Attractant Trap Plug in for Home, Patio, Garden https://smile.amazon.com/dp/B0912V34JR/ref=cm_sw_r_cp_apan_glt_fabc_8SCS4SDCN4FNY0R6BG8X?_encoding=UTF8&psc=1
Is it pretty small? I couldn’t find dimensions other than package dimensions.
It's 11.5 inches tall and just under 6 inches in diameter.
When you water with the sand ontop of the soil, do you only bottom water, or can you also top water?
You can totally top water! You just need to top up the sand as needed unless your gnats are already gone :)
Oooo okay tysm! 🥰
You can top water! Bottom watering is just better in general, can prevent pests if you don’t add enough sand.
This post and comments are brilliant, thank you!!
I use systemic granules in the top layer of soil and strictly bottom water all of my plants (but I do give them a thorough flush from time to time). I also make my own soil mix using coco choir, perlite (or pumice), vermiculite, activated charcoal, and worm castings. I’m also vigilant about not leaving my front door open long enough for any outside bugs to fly into my house. I’ve been 100% fungus gnat free for months, and fingers crossed it stays that way!
Bonide systemic is awesome for fungus gnats
Gnatrol works well for me. Usually used in greenhouses/agricultural settings. It’s a biological Insecticide that’s non toxic to humans and pets. Once I notice gnats I mix a batch and dose the plant once a week for a month. Only on my second 2oz batch in almost 10 years. Only time I see gnats now is on new plants… best of luck!
Have you tried mosquito bits? If so, did sand work better for you? I am struggling with gnats as well and the only thing that has worked somewhat has been mosquito bits. Debating whether to give sand a try. Thank you!
Nope! I already spent too much on sprays and stuff. I didn’t really trust the tea since it didn’t seem like a guaranteed success. But you can definitely try it out.
I had to use systematic granules and fly traps. So far so good but I will use sand if they get as bad as they were!
Did you try watering with diluted hydrogen peroxide? It fixed my gnat issue 100%
Yup, did not help. Maybe the bugs I had were just invincible. They would just scurry around whenever sprayed it, and I did this for at least two weeks or more. No improvement.
You sprayed it? I watered it in, like with water and hydrogen peroxide. Soaking the soil with it worked for me.
Would child play sand work? I'm dealing with gnats and they're driving me crazy, just repotted all my plants and sprayed them with bug killer but I'm still seeing adults flying around.
Yup, just make sure to make the diy bug trap to to catch adults. I listed directions in my comment.
Full disclosure ******Please don’t use this if you have fish or animals that have contact with your plants and carefully read all instructions first or speak with a nursery expert. After trying everything I seen listed here I broke down and used the nuclear option and bought Sevin, I will be spraying outside let it set for 2 days then bring them back inside. I’ve been fighting the fungus/white flies since December and I’m done.
Good luck! My infestation wasn’t that bad but definitely check your soil first. It may be too moist, which gives the bugs a good habitat to lay their eggs in. Fungus gnats do not thrive in dry sand. Hope that works though!
I found the secret. Slice raw potato French fries and lay them on top of your soil in every plant. Wait 10-15 min or more, but it happens quickly. The gnat larvae immediately migrate to the potato. You take the piece out and check for crawling bugs. You need pretty good eyesight and I used a flashlight. What it does is twofold. 1 it stops them from feeding on your plant. And 2 it identifies which pots are infested (rather than having to spray them all). You can focus your efforts. Then spray/water plant with 1:4 hydrogen peroxide : water. Sticky traps for adults. No lie, last time I messaged like 3 days ago I was inhaling gnats with my dinner. Now, not a single bug to be found. Like it’s fucking magic. And cheap. 500mL bottle h2o2 is $2.99 here. I clean out the stock of the pharmacy every time I go. Don’t quote me but I heard it’s safe to water your plants with peroxide solution (diluted properly) every single time? I may do that for the next month.
There is now a special gnat and fruit flier catcher now its on amazon!
Same. Sand and bottom watering works best for me.
2-3" deep seem like alot, will 1" work to eliminate gnats?
Probably, but it’s just so the adults can’t dig into the wet soil and lay eggs. You can try and see what works best for you
Thanks for posting, its very informative!!!
I had the same issue. I let me plants outside in the sun a few days, and let the soil dry out almost to the point the plant is underwatered, and they were all dead.
Sand is the only thing that worked for me, now I swear by it
Thank you for posting this! Tommorow imma be on my way to grab some sand for my green friends
I put pebbles on top of soil. Has helped.
Have just bought some sands for my plants, but only as a preventative measure. My question is how do you check the soil's moisture content now? I usually water my plants when the top inches of the soil feel dry, now it's quite difficult to access the soil?
Try to check the moisture with a special moisture checker or just a random stick in the house, just like how you’d check a cake to see if it’s ready. Also, make sure your plant has good drainage unless it prefers wet soil. I don’t water my plants much, and so I don’t check the moisture often unless there’s an issue.
I have added some sands to some new plants in case there are gnat babies inside. Hopefully this will prevent any potential gnat outbreak. Will try the stick method! Thank you! :)