Cold Stratification
- emilythyme
- Jan 14, 2025
- 2 min read
Updated: Jan 8
You've got the gardening itch? January is a great time to stratify your cold loving seeds!
Many of our perennial herb seeds require a period of cold stratification. Cold stratification is a process of simulating the natural conditions required for a seed to germinate. In the case of the seeds listed below, the stratification method needed is to subject them to a period of cold and moist conditions.
Here are seeds to stratify:
How should I cold stratify my seeds?
Stratify in your fridge:
Mimic these cold, winter conditions by placing seeds in a plastic bag along with a wet cloth or paper towel in your refrigerator and leaving them there for a month or more. It is wise to mark your calendar so you know when you need to take them out. Your seed growing instructions may indicate how long of a cold period the seed requires. For example, Echinacea purpurea calls for 1 week, while Echinacea angustifolia requires 3-4 weeks.
Stratify outdoors:
If you're in the Northern states, use the chilly winter weather to your advantage and sow seeds requiring cold stratification in pots or plug flats then set them outside to be exposed to the real deal. If you go the natural route, be sure to cover your pots with fine wire (like an old window screen) to let moisture in but keep hungry foraging critters out.
What supplies will you need for outdoor stratification?
The elements you will need to cold stratify outdoors include a seedling plug tray (we use 1-inch plug size), seedling mix, a fine screen and a cover that will allow rain to pass through but keep the critters out and the mesh in place.
After bringing your seedling flats into a warm space such as the greenhouse, you will start to see growth. Allow your plants to grow until they have developed their true leaves before transplanting up into a larger pot to continue to grow until outdoor overnight temperatures warm and soil is ready. Be sure to harden off your plants by setting them out under shelter for 3-4 days before planting to avoid shock.
As always, have fun and keep growing!
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