Prepare peat or other biodegradable pots before removing the butterfly weed seeds from the refrigerator. Fill 3-inch starter pots with a mixture of half seed-starting compost and half coarse sand. Moisten the mix and press it firm.
Leave the bucket outdoors for two or three days to let the fluff blow away. Stir the seeds occasionally to loosen more fluff. Do not worry if some of the fluff remains, since it won’t inhibit the germination process.
Before you begin to harvest the butterfly weed pods, sterilize your cutting tools. Dip the blades into a full-strength household cleanser, such as Lysol or Pine-Sol. Repeat between cuts to prevent the spread of diseases.
Place the butterfly weed seeds in a plastic bag filled with 1 cup of moistened perlite. Store the bag inside the refrigerator for three months. Mist the perlite with water every few days to keep it from drying out completely.
Watch for germination in two to three weeks. Turn off the propagation mat one week after the seeds sprout. Move the pots into a cold frame outdoors or against a south-facing wall with noonday shade.
Arrange the starter pots on a propagation mat near a source of bright, indirect light such as near a partly shaded south-facing window. Set the temperature on the propagation mat to 86 F during the day. Turn it off at night.
Butterfly weed and milkweed seed pods may be harvested and planted to support Monarch butterfly caterpillars. Butterfly weed grows well from seeds, which must be harvested in late summer and either sown immediately in the garden, or started in spring after a lengthy chilling process. The seeds are viable and will germinate with little care, although they must be planted at the appropriate depth to ensure successful sprouting.
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Share your tips for how to harvest butterfly weed seeds in the comments section below.
How To Harvest Butterfly Weed Seeds Step-By-Step
You don’t need to plant them very deep. The rule of thumb for planting seeds is to plant them twice as deep as the seed is wide. I would plant butterfly weed seeds maybe 1/4″ to 1/2″ deep. I would space them 2-3 inches apart, and then thin them so they are about 12-16″ apart once the seedlings start to mature. You can also just spread the seeds over the top of the dirt if you don’t want to be fussy about it. That’s the way Mother Nature does it. 🙂
Amy Andrychowicz says
Yes, unfortunately it does sound like you harvested your butterfly weed seeds too soon. It’s weird that the seed pods were brown and cracking open before the seeds were mature. Are there any other pods on the plant? If so, wait until the pods open up and the white cotton is starting to stick out before harvesting them. Otherwise, I think you’ll have to wait until next year. You could try planting the seeds you have and see if they’ll grow though, you never know.
Butterfly weed is a member of the milkweed family (Asclepiadaceae). The genus name Asclepias is named after the Greek god of medicine Asklepios. The species name tuberose refers to the tuberous (knobby and with swellings) roots.
Butterfly weed grows commonly in dry open habitats and is very common in the prairies and grasslands of the Midwest and Great Plains. This beautiful native wildflower is found from Maine to South Dakota to the desert southwest to Florida.
Butterfly Milkweed (Asclepias tuberosa L.)
Butterfly weed is commonly planted in formal garden borders and in meadow and prairie gardens. This wildflower does not transplant well as it has a deep woody taproot. It is easily propagated from seed. Collect the seed from the pods has they just begin to open. Butterfly weed seed need a three-month cold stratification. Therefore, it is best to plant the seed in autumn and they will easily germinate the following spring.
Butterfly milkweed (Asclepias tuberosa). Photo by T.G. Barnes.
Butterfly milkweed (Asclepias tuberosa). Photo by Daniel Reed, courtesy of the University of Tennessee Herbarium.