frost seeding is what some call it. basically, broadcast seeds by hand or tool early enough in season to allow the freeze/thaw cycle to implant the seeds into soil. this requires contact with soil and solar exposure, though. also, some species seeds require stratification before proper germination. often that’s a cold strat like over winter conditions - but sometimes it’s heat from a fire, replicated by prescribed fire disturbanceWinter planting is the best way to propagate milkweed. I forget the details but the seeds overwintering on the ground helps them to grow in the spring.