Gnat problem?

I think I may have some gnats. I have three plants coming up on 5 weeks vegging under 250w HPS, Roots organic soil, no nutes, water at a pH of 6.5 .. Room temp is also at 80 degrees, and the tops of the leaves are at 73. And I have noticed a few gnats flying around. All of the tips at the ends of the fan leaves have been curling down, started on all of the plants about 4 days ago. There is no yellowing anywhere, all the leaves are a nice green. I placed potato slices an inch into the soil to see if I get any larvae, I heard Roots has been having problems with gnats lately. I took these pictures about an hour after they were watered.


So, possible gnat problem?

i have the same problem, do you have fans blowing? that takes care of them.

that would be an awful lot of gnats. why no nutes?

gnats would make sense, they like it wet and your plants look a bit overwatered. let them dry really good before next watering and like other said, it`s an easy one to get rid of if you take care of it right away.

It look like I got rid of mine, I dont see anything flying around anymore, I did the habaneros solution, I sprayed every other day for 6 days.

Endur0xX said:

gnats would make sense, they like it wet and your plants look a bit overwatered. let them dry really good before next watering and like other said, it`s an easy one to get rid of if you take care of it right away.

It look like I got rid of mine, I dont see anything flying around anymore, I did the habaneros solution, I sprayed every other day for 6 days.

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If I am going to take care of the gnats, most likely just going to go with D. Earth. I last watered them last monday, and the soil started to feel a little dry yesterday, so I decided to water today. I am watering with about 2L of water in 5 gal. pots

scroglodyte said:

that would be an awful lot of gnats. why no nutes?

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I didnt go with nutes because of money, and I heard RO was a pretty good soil to begin with. When I start to flower these in a few weeks, I'm going to introduce nutrients for flowering.

Oh yeah, and btw I forgot to mention, this is my first grow.

Mosquito dunks work like a charm for me. I crushed up a 1/4 dunk and sprinkled on top and water regularly to my schedule, then boom in a few days those suckers were gone. Also topped my soil with perlite.

benign said:

Very possible...I use Roots Greenfields and have a similar problem, luckily it's probably one of the easiest bug issues to solve just order some Food Grade Diatomaceous Earth and sprinkle it over the top of your soil and you should be good to go. It's cheap too around 12 bucks for 10lbs

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Sorry for the double post, but this is one question I cannot seem to find a strait answer on. If I were to sprinkle D. earth on the soil, would I be able to water right on top of it? I heard D. Earth tends to turn clay like after getting wet then drying

i too just solved a gnat problem. I crushed up one mosquito dunk per 5 gallon pot and placed on top of my growing medium (coco and hydroton). That cut down on their numbers a lot. However, gnats were still able to lay their eggs in the holes on the bottom of the pots. That area seemed to be unaffected by the dunks. So... I taped half a used fabric softener sheet around every hole... on every pot. That stopped anything from moving in or out. No bugs within a week. I'm proud to declare I am bug free today. In the future I will be filling my pots 1/3 full... adding half a crushed dunk... then filling full and sprinkling with the remaining half dunk. Mosquito dunks are like 10-12 bucks for 6.

prep1801 said:

i too just solved a gnat problem. I crushed up one mosquito dunk per 5 gallon pot and placed on top of my growing medium (coco and hydroton). That cut down on their numbers a lot. However, gnats were still able to lay their eggs in the holes on the bottom of the pots. That area seemed to be unaffected by the dunks. So... I taped half a used fabric softener sheet around every hole... on every pot. That stopped anything from moving in or out. No bugs within a week. I'm proud to declare I am bug free today. In the future I will be filling my pots 1/3 full... adding half a crushed dunk... then filling full and sprinkling with the remaining half dunk. Mosquito dunks are like 10-12 bucks for 6.

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I am more than likely just going to go with Diatomaceous Earth.. Its basically considered the nuclear bomb to gnats, so i hear

a fan aimed at some fly paper sure puts a hurtin' on their population. i also have a resident assassin bug living in my box, and he seems well fed. i mean......my friend in California's box.

i'm spoiled when it comes to nutes. i have room for composting and worm ranching. i pick up rabbit crap, coffee grinds, tea leaves, etc. from ads on Craigslist, and keep a couple of piles going. there are free nutes out there, and that's my favorite price. alfalfa meal is a cheap source of many of the nutrients plants need. its animal feed, so its not a lot of ducats. coffee grinds contain a lot of N. happy farming!

I had gnat problems and I used the potato slices (which I never saw larve) also used cider vinger in a cup next to the plants. and the only thing that really worked is putting a thick layer of sand over the the top layer of my soil. the only thing that sucks about that is after a few waterings the sand mixes with your soil and evenetually the gnats come back. I hate those little fuckers, Im afraid everytime I water that I will see them again. they really did a number on a few of my plants/.

looks like u may be overwatering. compare the weight of your soil in containers from wet to dry, then check your plants by lifting them, if the containers feel light, then water. after a few times, you'll geit the hang of it, just make sure you water them before wilting occurs. as far as your gnats, they problably came from your soil as i have gotten them from ro greenfields and green lite. Gnats love high humidity so lower it a bit and use fly paper or the yellow(not the blue)leaf hopper strips( hang them from lower branches if possible). also try using a few inches of coco fibers on top of your soil for it will make it harder for them to get to the soil to lay larvae and you can put organics such as worm castings, bat guano etc.. on top of coco fiber and water without the organics getting compacted onto the soil. As long as your plants are big enough( not in seedling or clone stage), the gnats shouldnt pose any real threats. the larvae eat young roots so as long you have a good root base, you should have no worries. Just remember, the most common problem with growers is overwatering. It is very important that the soil dries out a bit to supply oxygen to the roots also gnats love wet soil. i hope this helps

forgot, if the gnats are going through the bottom holes of pot, place nylons around the pots. will prevent the gnats from getting in and still allows for drainage

I just used those yellow sticky traps. Apparently the gnats are attracted to yellow, or so the traps say. It worked for me!

If you do have gnats really bad in soil. try using 15 ml/gal of h2o2, just make sure you flush 12 hours later. this will kill all larvae and the traps will get the rest. just make sure you dont have any opened or unused bags around area and always keep area clean and pick up dead leaves and unwanted debris ( they love to hide under them).i have had many issues with gnats and have tried many things and i find the above to work best. As long as you can keep them controlled, you will be fine. A few gnats will be ok. i hope this helps and good luck

the top of the pot is easy to control... its the holes in the bottom that you have to worry about. You have to cover them. I used fabric softener sheets... I guess another guy used nylon. you have to do something about the holes on the bottom.

I just bought mosquito dunks, I couldn't find any diatomaceous earth locally. When I use mosquito dunks, would there be a need to flush a couple days later? also for those who are saying I am over watering, are you referring to frequency, or the amount? I last watered on Sunday, but the last time before then was a week before. I just checked the soil today and the top inch and a half or so was completely dry after watering on Sunday. And one of my plants aren't starting to look good, the leaves are starting to curl down even more.

you can use RW 2" blocks cut in half to block of the holes in you pots. It keeps the dirt in and the bugs out, they can be reuse lots of times. D. earth is your best weapon ionized air from a air purifier also kills the little bastards , i got a old school bathroom scale i use to check my pots weight with and its spot on every time, i can check mid watering and know exactly how long i have before i need to water, scales dont lie, but a injured back like mine will lol