I started seeds of several milkweed species indoors under lights in early spring. I had good germination, but the milkweeds were slow growing and spindly, even though they were close to the lights which were on for at least 12 hours a day. Once they were large enough and the danger of frost was over, I started getting them used to going outside. They started off in our screen tent and eventually were planted in the garden. I also started seeds right in the ground about the same time I was conditioning the indoor starts to outdoors. The ones in the ground germinated and grew well, eventually passing the ones started earlier indoors. I don't think I would bother starting any inside again. This was for a variety of native species, I would, however, start the tropical milkweed indoors. The tropical grows better indoors than the native species and it needs that head start to make sure it flowers and produces seed pods to give seed for next year.
Everyone's conditions vary, and those are only MY results. What works best for one person, may not be the best option for others. The seeds I sowed in the ground were placed in areas of new triple-mix garden soil, with a soil-less potting mix in the imediate area of the seeds. The area was kept well watered and new seedlings were protected from the hot mid-day sun until well established. I found that the swamp milkweeds (for me) grew faster than others such as Showy, Clasping and Poke.
Most of my milkweeds are for decorative purposes in the garden, but they provide nectar and plants for egglaying. Of course leaves are lost through egg collecting! We still collect milkweed from wild patches for feeding our caterpillars. I have plans to grow more milkweed for feeding purposes and I will try the fall sowing method for this new area.
John Beaulieu & Brenda Stride
Midhurst, Ontario CANADA
MONARCH WAYSTATION NO. 553