The Prairie Moon catalog had an interesting article on cold-stratification. Here are the basics.
- 1/3 cup silica sand – you can find this at some hardware stores or pet stores. It’s different from regular sand
- Add and mix 1 to 2 tsp of water so that the sand will clump into a ball.
- Add seeds – 1/8 ounce.
- Make a note as to how long the seeds need to be refrigerated.
- Put mixture into a plastic bag which can be sealed. Mark the bag ahead of time with the type of seeds and the dates.
- Put the bag into a refrigerator.
- Mark your calendar to take the seeds out of the frig.
- Plant outside when they danger of frost is past.
The Prairie Moon Catalog tells you how long you need to do cold-stratification for each plant. Here are a few examples.
- Echnacea – no pre-treatment necessary.(Germinates in 2-3 weeks)
- Most native milkweed – 30 days
- Liatris – 60 days