Greg Pearson shares his expertise about getting milkweed seeds to germinate and grow into healthy specimens.
All native milkweed seeds except A. perennis need pretreatment prior to attempting to germinate the seeds. Cold storage in your refrigerator is not enough. The seeds need to be subjected to cold moist stratification (CMS) in order to produce a good yield of germinating seeds.
- Drill a drain hole in the bottom of an eight-ounce plastic cup and then fill the cup with vermiculite.
- Pour three eight-ounce cups of distilled water or rainwater through the vermiculite and then let the vermiculite drain for a few minutes. This procedure gives consistent results. Vermiculite that is too wet or too dry can lower your germination percentage.
- Place two or three tablespoons of moist vermiculite into a baggie. Add your milkweed seeds (20), seal the baggie and shake.
- Place the baggie into your refrigerator for 30 to 60 days.
- At the end of the CMS treatment place the baggie in a warm spot and watch for germination (two days to two weeks depending on the variety).
- Transfer the seedlings to a seed tray or a small pot. Adding a small amount of mycorrhiza to the soil produces healthy plants.