I have no experience with the product that you are talking about, but I really do believe that as long as you are not allowing the water in the birdbath to sit stagnant for several days (I would think at least a week or more) then you are not going to be having mosquitos hatching in the water. I am under the impression and also from the experience of having a birdbath and spraying it with fresh water every few days, that mosquitos need still water to be able to lay eggs and hatch. As long as you are spraying fresh water and probably also spraying hard enough to spill the old water over the edge, then you are going to be perfectly safe and don't need to take the risk of using any kind of chemical and having possible harm coming to anything whether it be the neighbour's cat or dog or the birds or insects which will come to drink.

momma, float the dunk in a container of water overnight, then use that water to water your container plants as you normally would. At least three consecutive times on your usual watering schedule, expect it to take three or four weeks to kill any hatching larvae and stop the breeding cycle. I brought the gnats home in a new indoor plant once (I saw them around the plant in the store and didn't realize their significance) - ended up with them in every container plant, some that were decades old. I don't over water. My feeling is that keeping soil on the dry side might prevent them from establishing, it wasn't helpful in eliminating an infestation. Years later, as I'm growing more from seed and need uniform moisture, I prefer the liquid form of BTi for convenience, but the dunks method does work.

I started feeding my seedlings when they got their second set of leaves, or thereabouts. They get a dilute solution of fish emulsion and seaweed each time I water. Soap is okay on larger seedlings with good roots, especially if the aphids are particularly persistent. I don't use it on really small seedlings (I figure there's a reason that it's not labeled for use on cuttings, and I want to be cautious.) For these, a sharp spray from my squirt bottle can be enough. My understanding is that fungus gnats are attracted to the damp organic material on the surface of pots. The layer of perlite is inorganic, and it prevents the gnats from getting to the soil. It also helps with damping off. Connie

I have never used them myself but I know "Bacillus thuringienis israelensis", the active "ingredient" in Mosquito Dunks will kill fungus gnat larva it is comes in contact with them so I see no reason why it should not control a population in your bin. I would use 1/2 a dunk and soak it in the recommended amount of water and use this treated water to soak some bedding in and mix it into the bin. Fungus gnats like wet conditions so after application I would let the bin dry out on the surface to further discourage any remaining adult gnats to lay eggs back into the bin. I had a gnat problem the first summer I had my bin. I think they started in the worm bin and quickly spread to all houseplants and then started swarming in the kitchen. I applied beneficial nematodes to some coco coir and used it to top dress all plants and dumped the rest into my bin. I have not had any fungus gnat problems since. I believe Bentley is experimenting with dunks on his blog now and may have more/better info... Here is a link that might be useful: Can Mosquito Dunks Kill Fungus Gnats and Fruit Flies?