It's a multi-step program. First, you might want to take a good look at your potting medium. Perhaps it doesn't drain rapidly enough or is simply too fine-textured. Second, make sure that you aren't watering too much (frequently), which can be easy to do it the potting medium is not a good one. Keep the greenhouse floor as clean as possible. Provide good air circulation. Then, applications of Gnatrol (or other Bt-i) during your normal watering regime will get rid of the larvae, if you follow the directions. Repeat applications will be required, of course, until all of the existing adults are dead and gone.

Re: hemnancy I think I also got infested from a plant that came from outside. I wanted to see if I could get pomegranate to grow from seed off of a store bought pomegranate back in November. I also tossed in a Brandywine seed or two from a seed packet that I purchased at the grocery store at the same time (November). Three poms and one BW sprouted. So far, I've been able to keep all the plants alive all winter by bringing them into the garage on cold nights and letting them out in sun during days above 40 degrees. The BW is a short, stubby plant that I've become attached to and I really want the poms as the plants cost at least $40 at the nurseries that I've been able to find them at. Anyway, sometime last fall, the pot that all these plants sit in became infested and that infestation has spread to my Jiffy peat pellets and a couple of seed trays. Re: ekgrows I bought a can of flying insect killer. It's not as organic as your method, but if become a problem, it is an option to me. Also, I've purchased the mosquito dunks and put a chunk of one in a spray bottle and wet down all my pellets with it. I know that it's too soon to tell if it is working, but since last night, I've seen one gnat that I smashed with my finger. I plan on starting to move the peat pellets to peat pots now that I have a method of control. I plan on spraying the inside of the pots using the spray bottle, spray down the potting mix that I'll use and cover the entire thing with sand. I'm thinking that this one-two-punch approach should be effective. I'll let you guys know how it works out.

Nothing in your bin will hurt your worms (except on rare occasion). When you do see something seem to be prospering better than the worms, it is telling about the environment of your bin. Go to happydranch.com and click on their invertebrate page. Lots of good information there. I doubt you can see springtails but check out potworms. Keep a good 3" layer of shredded paper on top of your food at all times. The newspaper that is under your bin can be shredded and added to your bin also, or put in an outdoor compost pile.

Another factor may be the amount of organic/decaying material in the medium, which the larvae feed on. Two plants I've had fungus gnats in had both been repotted into fast draining 511 type mixes, and allowed to dry down between waterings, but had some root rot issues I wasn't on top of and I'm sure that was key. Adjacent plants in moister finer soil were unaffected. Seemed bit backwards. My ferns (ladder, button, doryoptis) are keep pretty consistently moist - I barely let the surface of the soil dry out - and the gnats haven't gone for them. So I wouldn't rule out a whole category of plants just because they like moist soil. I think there's more to it than that. By the way, are the houseplant fungus gnats the same insect as the gnats out in the garden? Which we have clouds of?