Fungus Gnat Problem

[knowledgeable]

So IK there are many threads and websites about this already but I have a question about these things. They are supposed to be attracted to the color yellow and I think they are but unfortunately my lights are 2700k cfls and have a yellowish color. So they are up in my lights and not sticking to the yellow sticky sheets. Any suggestions? I need them to not multiply so i need them out asap.

 

[jojo677]

The flying gnats aren't the only ones you have to worry about. You also have to kill the larvae, which live in your medium. The first time I had them, I sprayed every inch of my plants with dilute neem oil, and they disappeared in a few days.

I'm fighting them again now (several weeks later), and the neem oil isn't completely working, but they are flowering so I don't want to spray the buds. I'm guessing since you're using 2700k you are flowering also? You can treat the medium with a 4/1 ratio of water to 3% hydrogen peroxide, after letting the top few inches get fairly dry. This will help kill the larvae. Then you can use another method to kill the flying adults. Neem oil or other pesticides. It's a lot easier to kill them in the vegetative stage, since you don't have to worry about contaminating something you'll consume.

 

[knowledgeable]

The flying gnats aren't the only ones you have to worry about. You also have to kill the larvae, which live in your medium. The first time I had them, I sprayed every inch of my plants with dilute neem oil, and they disappeared in a few days.

I'm fighting them again now (several weeks later), and the neem oil isn't completely working, but they are flowering so I don't want to spray the buds. I'm guessing since you're using 2700k you are flowering also? You can treat the medium with a 4/1 ratio of water to 3% hydrogen peroxide, after letting the top few inches get fairly dry. This will help kill the larvae. Then you can use another method to kill the flying adults. Neem oil or other pesticides. It's a lot easier to kill them in the vegetative stage, since you don't have to worry about contaminating something you'll consume.

Hey thanks for the info. I already did the hydrogen peroxide, Im not in flower which I guess is good but I'm in the 1 st week of veg so the seedlings has very sensitive roots. Im just worried about the adults being a problem. Ive been super careful with my babies so its bothering that the sticky sheets don't work. Idk where to get neem oil but hopefully I can find a home remedy. I read about cinnamon or something but idk. I might try that or some type of pesticide

 

[jojo677]

The big box stores (Home Depot, Lowes), hardware stores, or places that sell plants should sell neem oil in the pest control section. I've been using it over the last few days, and I've seen the adult population drop dramatically. The trick is to keep treating for a few days after you stop seeing them, to make sure you kill the larvae too.

Another treatment I've read about is coving the top of your soil/medium with sand. I think they mentioned a layer about 1/2" thick, but supposedly the larvae can't get through it and die. If you have some sand around, it couldn't hurt!

 

[bozzo420]

1/4 inch of sands and it smothers the larva. as soon as sand is on them ,your gnat problem is gone in dirt grows. gnats are easy to get rid of.

 

[knowledgeable]

1/4 inch of sands and it smothers the larva. as soon as sand is on them ,your gnat problem is gone in dirt grows. gnats are easy to get rid of.

Hey that looks like it would work pretty well. Is there anything besides sand I can use? Idk when I'm gonna be able to get some. Also wont the sand smother the roots too. And will the sand add salt to the soil when I water

 

[drgreenthumb4]

if your in veg than why are you using that k rating of cfl, you need the higher k number if im not mistaken, thats why the other guy assumed you were flowering bc most people would use the 2700 for flowering and the 5000 or 6500 k for veg, just trying to help . u can do it , if i can , then anyone can....bc im no smart guy, by any stretch

 

[drgreenthumb4]

if you can avoid pesticide, you will be glad u did, keep it as organic as possible, since ur n veg u should be abke to easily remidy the problem with neem oil or sand, or both, ether way. u have plenty of time, just try and make sure they r healthy when u switch the lights on them ...8 weeks is a good amount of time to veg, and if u have a jewlers loop.....u usually can see preflowers buy eight weeks or so i read , my experience is limited. but ive been on out of work for 6 months due to an accident so ive had nothing to do but research and get baked....so anyhow....good luck, oh....good light, good dir(fox farms ocean forrest, and good air ventalation , humidity no higher than 50% and temps between 70-80 during there day and hopefully no more than 20 degree temp diff at night, but ten degree difference is much better of night temp, i was only saying 20 degrees + diff at night ant u would likely have problems, good luck ....wright everything down , keep track of the weeks, and when and how much they do everything, and as far as using cfls, tons of haters that hate cfls, but if you use maybe fifteen per plant placed all around her bc u need not flower top to be any further than 2 inches away from a bulb, i know thats a bitch, but if u can do that than likely u will have better results, i did great with some generic cfls

 

[Icemud]

Here is the solution that has worked for me in the past..... its a 2 part process.

First, get 2 things.... mosquito dunks or a BTi product, and yellow sticky cards.

Take the yellow sticky cards and place them all over your grow area, in the shaded spots where the fungus gnats love to hang out... (below the canopy, near the soil, rip a few yellow sticky cards in half and lay them on the soil).This will catch and kill the adult fungus gnats.

Next, use the mosquito dunks/BTi product for 1 month. I use about 1/2 a dunk per 5 gallons of water, crush it up in my fingers and then feed the plants. BTi will kill the young eggs/larvae in the soil.

From what I have read, fungus gnats life cycle lasts about 30 days, so repeat treatments for about 1 month is necessary to eliminate the issue.

Also adding yucca extract to your feedings will help repel the pests....

This process has worked for me a few times, and never had issues after using it.

 

[jddrews]

I've had success with perlite. Remove the top inch of soil to get rid of any eggs/larvae and replace with an inch or so of perlite. More breathable than sand and serves the same purpose. Looks nice, too. I also put yellow sticky tape at ground level for a couple of hours to catch any gnats still lingering around. Don't want to trap the good guys, though, so don't leave the tape up for very long.

 

[Dave Groomer]

Hang fly paper.