Hairy Balls Milkweed (Gomphocarpus)

Very easy to sprout the hairy balls seeds in small pots outside zone 8b in September. . Large amount of die off/damping off when seedlings were 2 inches tall in October. Now I have 3 seedlings left surviving but they have stopped growing. Getting cool. Maybe better to try to sprout in the late spring in z 8b. Will try to over winter the remaining sprouts inside.