Best germination is at 65 to 80˚F. I was amazed this year to watch a single older migrating female Monarch lay her eggs on the flats of Asclepias seedlings on my deck for at least four hours. I would try to speak with someone in your region that has actually used milkweed seed bombs before, to see how effective they are. Just be sure to poke holes in the containers so excess water can drain off. Who Knew!