Fungus gnats suck and would be extinct if I was god, but I’m not, so Ill do the next best thing and destroy any of them in my household. These pesky little flies start off their life as maggots which eat the organic matter on the top two inches of your soil and they will also consume your plant roots. They can also spread disease to your plants and what results is leaves that look like this and sproutlings that may not survive. There is two methods I use to get ridd of them completely and as long as you are willing to work for about 2 weeks, you too can have them gone for good.
To kill off the larvae or maggots, I use a mosquito bits tea. To make it,
I use 4 tablespoons of mosquito bits per gallon of warm or room temperature water. I place the bits in a mesh bag which I submerge and shake occasionally for 6 hours before the tea is ready.
The active ingredient in mosquito bits is BT which is toxic when consumed by the larvae.
Harmless to people, plants, and pets, Mosquito Bits® can be used on both ornamental and vegetable plants and will effectively eliminate the fungus gnat larvae that grow in the potting soilMosquito Bits Sell Sheet
For more information on BT, Check out this FAQ
You want to water your plants from the top and completely drench the top 2 inches of the soil. To play it safe, I let the water pool on the top at least 3 times. Then I let the excess water drain out from below.
The larvae lifespan is up to two weeks and the eggs are up to 6 days. So, you should rewater with this tea for another feeding or two to make sure they’re gone. Now the tea gets rid of the larvae.
You still have to worry about the flies. Flies can lay up to 200 eggs in their 7 day lifespan as a fly. To kill the flies, I use yellow sticky traps.
Have them hanging around your plants for a couple of weeks until you don’t notice any new flies getting stuck.
Now that the gnats seem to be gone there are 2 methods I use to further prevent them from appearing. The first is to bottom feed. Which is where I fill up a container with water and let the plants absorb water from the bottom. This takes about 2 minutes to absorb.
leave the top two inches of soil in my pots dry. So, the gnats have no moist soil to lay eggs on. The second method is the use of fans which make it too inconvenient for gnats to land on the soil.
I can honestly say: I have safely removed these pests forever.
All of my videos recorded since have ZERO pesky gnats flying around.