Fungus gnats

woody333333 said:

http://en.wikipedia.org/wiki/Diatomaceous_earth

Click to expand...

I love the stuff. I had gnats when I started this recent grow and it took me a while to get rid of them. The final thing I did though was dust the top surface of your soil with diatomaceous earth and the drainage holes when they're relatively dry. Let it sit there for a good 2 days and the gnats will start to drop, when you water it's like it just disappears with seemingly no affect on the plants. I also did a final watering of Mosquito dunk water to kill of any leftover eggs/larvae that were still in the soil. Haven't seen another once since, just dead ones .

To dust it i just filled up a dry empty water bottle, and poked small holes in the cap. just a gentle squeeze and the dust comes out

A few fungus gnats in a large container is not much of an issue if you are only a few weeks from finish, the issues is as they multiply they will naturally move around and infect other plants, as the populations grow...the problem multiplies. Because a few fungus gnats in a clone box or other young plants will defiantly be an issue and at best will cause slow growth, worst will be so much root damage that it can lead to disease and death.

I just found the initial signs of a fungus gnat population on a coco grow that I am consulting on and will be starting an immediate chemical free program of most of the above mentioned products. Sticky traps to monitor adults, BTI into my mixes, DE and finally predators and nematodes.

Get em early and do it organically...I hope to have some very good news in the next few weeks.

Thank you so much for the help everyone! Just wanted to let you all know that your advice really helped out. I managed to kill all of them in my flowering room within about a week of getting my products. The gnat nix seemed the most effective to me, followed by the gnatrol & sticky traps on Popsicle sticks.


i hadn't seen any for about two weeks, then two days ago I saw one that managed to somehow get into my 9 vegging plants :/ back to the drawing board lol. I bought a 50 pound bag of D.E. powder so hopefully I have good luck with that. I will post results. The only problem with the D.E. powder is my drainage pans are to small so I can't really cover up the drain holes. Won't they just go & lay there eggs there? Anyone have any ideas to cover up drain holes when drain pan is to small for for container to sit down in it?