You have to be living in a hole if you have not heard of the concern for the decline in Monarch populations across the United States. Much of the loss is thought to be destruction of habitat and of the native milkweed species that provide food for the Monarch larvae. In response, many organizations have started propagating milkweed and in some cases are giving away free milkweed seeds. However, if you are lucky enough to stumble upon a patch of milkweed close to where you live, you may want to collect some of the seeds yourself.
For all the hype of milkweed being a weed, in the case of Showy Milkweed (Asclepias speciosa), it sure does not spread like a weed. It is difficult to start by broadcasting seed on the ground and is best started in a greenhouse and then transplanted when it is about a year old. However, you will have greater success at starting Showy Milkweed from seeds if you can collect some seed from near your home as the environmental conditions will be similar.
With that being said, collecting milkweed seeds is a matter of timing. A lot of people say you need to go out daily and monitor seed pods as they do not all open at once. You want to collect the seeds as the pods dry and turn light brown but before the pods open up. If you collect the seeds too early they may not be fully developed and will fail to germinate. Seeds collected too early are typically light brown or white.
If you wait until the pods have opened, small milkweed beetles (Lygaeus kalmia) which are granivorous, may beat you to the seeds here in the Willamette Valley. These milkweed pests look much like our Western Boxelder Bugs (Leptocoris rubrolineatus) but can be distinguished with younger eyes than mine or a small hand lens. In addition, if the pods have opened the seeds are harder to separate from the fluff (coma) once they have opened.
The easiest way I have found to harvest the seed is to put a rubber band around each pods when they are fully formed and green to prevent them from opening. In that way you do not have to check your patch as often. If you are a little late the seeds stay protected from pests or wind. When they are ready, cut off each pod and drop into a paper sack.
When you get the pods home, take off the rubber bands, open the pods and grab the coma below the seeds. While holding firmly, you can rub off the seeds closest to your fingers. With those gone, choke up and hold again just under the remaining seeds. The rest should come off easily and all the coma stays intact. It really is that easy. One last note, please only take a small portion of the seed pods from a patch and leave the rest for nature to propagate.