Cold Stratification
What does it mean on the seed packet when it says, “seeds benefit from stratification prior to germination?”
Many people purchase packets of seeds in the spring with the intention of planting as soon as the weather gets nice and warm. Some seeds, however, will not sprout in the spring unless they have experienced a period of cold temperatures first; these seeds are in a state of dormancy. Seed dormancy is an adaptive strategy that allows plants to survive in climates with harsh winters. The plants drop their seeds in fall, and the seeds lie dormant until warm weather and moisture return. Once soil temperatures rise and rain comes, the seeds will sprout. If you try to plant these seeds in spring and they have not been exposed to the necessary amount of cold, they will not be able to break dormancy and germinate.
One way to deal with dormant type seeds is to plant in fall and allow nature to take its course. In some instances, however, fall planting may not be feasible or desirable. Fall planted seeds can be lost to wind and rain or be eaten by birds and rodents. Unfavorable soil or weather conditions may also lead to lower rates of germination. Or, you may have simply missed the fall planting window. If you want to plant these types of seeds in the spring, you need to chill them. The process of chilling seeds in order to break dormancy is referred to as “cold stratification.” Usually, this process involves layering the seeds in a moist, aerated medium, such as sand or vermiculite
and placing them in a refrigerator for as long as they need to break dormancy. Some gardeners have success placing seeds on moist paper towels or coffee filters set in plastic bags. Once the chilling requirement has been met, the seed will begin to exit dormancy and be ready to germinate once planted.
Because cold stratification can take up to three months for some species, you need to plan ahead so your seeds will be ready when you are. Seed packets may provide this information, or you may have to do some online research to discover just how much cold your seeds will need. If you are feeling spring fever now, you may want to give the “winter sowing” method a try as outlined by Rockwall County Master Gardeners here:
For step-by-step instructions for cold stratifying seeds, visit:
https://blogs.cornell.edu/…/stratifying-perennial…/
https://www.youtube.com/watch?v=ZR759sbEUcg
