Hi guys, fungus gnats keep coming back to one of my plants, I saw a video on youtube where a guy said he never gets gnats since he started using watering spikes cos the top soil doesnt get wet when you use them, but I dont have any and I would be frightened I damage the roots shoving things like that in it.
Iv been frying some sand in a pot on the fire today to dry it out and make sure theres nothing living in it. would a layer of sand be the best quick fix for it?
@stootie this problem comes up,frequently and you will get more than one answer to this problem. I’m going to repost a reply from me that explains my process. I grow in coco so the media is ALWAYS wet and gnats can thrive in those conditions. Here’s the post
First of all DON’T PANIC lol. I say that because most new growers think this is the worst, but if you have to get one pest, gnats are the easy one. Mostly they bother you far more than the plant but in severe cases they can slow down the growth, be a horrible mess and I’ve heard in extreme cases could kill a seedling. A biological control is available and I use it with 100% effectiveness.
These mosquito dunks have a biological toxin harvested from bacillus thuringiensis israelensis bacteria. This naturally occurring material is toxic to the larvae stage of fungus gnats and mosquitoes but not to other plants or animals or humans. This is a targeted approach aimed at one specific pest. I float the “dunk” in my water for a day or more before I water the plants. The donut is transferred from one bucket to the next one and last me the entire grow. The larvae ingest the toxin and it paralyzes the digestive system and so it can’t feed and it will die. No babies, no new adults.
Second option is to put a small fan blowing directly on the surface of the media. As simple as this sounds it works! I use small computer fans for this as I don’t want too much air moving down there which can dry the leaves out and cause other problems. Gnats are poor fliers and the wind is a deterrent to their flight. The air also helps dry the top layer of the media faster and that helps control the larvae that live in the soil. Keeping a dry layer on top the soil helps avoid gnats, they don’t like dry, but avoid starving the plants of moisture and remember that coco works best if it stays wet so watering a minimum of once daily with runoff is recommended. Whatever your course of action the plants health should always be a priority.
Hope some of this helps
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@monkeydo Cheers bud, sounds like that will fuck them up for good. I was going to order some of those yellow sticky things but never did because im only watering/feeding my plants about every 3rd day when the soil is dry and the gnats go away, but they keep coming back, I usually kill 4 or 5 each day and cant see any more by night, I thought seeing as I have sand I could try it but I wasnt sure if the sand would stop some of the nutrients getting through when I water them.
Im not really worried too much about the gnats cos theres only a few, they are just starting to piss me off. They have never gone near my other plant so there must be something about it that they dont like.
I'll get some of those dunks ordered right away, Thanks for that mate 
@monkeydo Cheers Monkey I think you've fixed my gnat problem, havnt seen any yesterday or today. Slam Dunk.lol
I just got an email from growell about a new product for fungus gnats, Lava-Lite No-Gnats
I still use dunks and they're working perfect, but thought I would share this incase anyone's interested
1 Litre is £6.99
3 Litre is £11.99
The dunks are pretty expensive but they last a long time, this stuff is cheaper but it might not be in the long run, could be worth a try sometime tho 🙂
@stootie, have you try a gallon of gas and a match? 😉 Much more cost affective. It's Monday, sorry. 🤣
@woodi2 We dont got US of A gas prices over here Hoss, I would have to sell a cow if I chose to petrol bomb the shower, But I do like to keep my options open so im not ruling the gas out just yet. lol 🤣 🤠
@macky Yea thats what I was kinda wondering too, I dont know if its just new to them and been on the go for a wee while or if its completely new on the market.
But seeing as its made specially for gnats you would think is should be good stuff.lol
I was going to order some of those yellow sticky things but never did
Always a good idea to have a couple, tells you instantly if you still have the issue 😉
@zn Yea Iv got ones a wee while ago, I wasnt expecting them to be so big, I thought they would be about 3" x 4" ish, I ordered a pack of 20 and when they turned up I thought it must be a book or something by the size and weight of the package 😆
I cut them in half got ones hanging in all my grows and I still use dunks, you still see gnats flying about now and then but I dont pay any attention to them anymore, they dont raise the same level of panic as they did in the first grow 😆
@stootie Yeah, they're not a massive pain in the arse...I have HotShot though, nothing lives 
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