Ok, so I have fungus gnats. I've researched how to deal with the adults around the plants and how to attack the damaging larvae. But what about eliminating them from the grow space entirely. I'm cutting this grow short and removing all the plants and soil and whatnot from the space. Wouldn't this render the room unsustainable for the gnats, let me start with a clean slate? Is there a way to pretty much assure they won't be ready and able when I start my next grow?
Fungus gnats lay eggs in the soil. No place to lay eggs means no reproduction. You can hand some fly paper to help catch the adults if they are really bad.
Neem cake mixed into or topdressed on the soil - plus the tacky strips of flypaper as suggested above. j
I like to place sticky traps across the top of pots to catch them as soon as they emerge before they have a chance to breed and lay eggs. A product called "gnat off" works very well. You put it in your water and water in. You only need one application and it kills them all and stays active for the rest of the grow. It's a bacteria and completely harmless to the plants. Mulching is also a good way to keep them from laying eggs. Straw works well, as does perlite
Another product that I've heard growers talking about with positive results, and I believe is similar to the product Gold Grower referred to is called "Gnatrol". J
a fan with a nice breeze also discourages them from sticking around. they're clumsy fliers that can't handle a good breeze. doesn't need to be much either.
I had a friend who had a horrible gnat problem he loaded the room with fly traps hanging and laying on the soil. He also added neem oil into his nutrient mix and as a foiler spray. I havent had much of a bug problem but Azamax for me knocks everything out in 3 - 5 days. Expensive though depending on your grow size.
add diatomaceous earth to your soil and put a layer of it on the soil in each pot once the plants are well established. the larva will be 'shredded' by it..and emerging gnats softer shells will also be 'shredded' http://www.amazon.com/Diatomaceous-Earth-Food-Grad... neem oil dr bonner soap d.e. these three things got rid of gnats and thrips for me, and they haven't come back.