That is good info about the Sevin. I am just now getting going on my planting, all of which is in 5" square pots on shelving in the basement. I saturated the pots with plain water to get the seeds going (were germinated under refrigeration). Going forward, since I did buy gnatrol, I plan to top dress with a small amount of gnatrol in solution each week and bottom water with regular water. My logic is that they gnats like to do their business generally in the top of the pot, at least to start. And, the organisms in gnatrol will find and feed on the larvae, multiplying as they go. I don't expect a complete weekly die-off of the BTI bugs, based on comments I remember from another thread.
However in the event that none of this works, I do have some old Sevin in the garage
