Learn how to use cold stratification to improve seed germination – & which seeds need it.
Have you ever bought a packet of seeds, planted them, and waited…and waited…and waited… And nothing ever happened? While it’s possible you got a bad batch of seeds, it’s also quite possible that the seeds needed cold stratification – especially if they were flowers.
Many flowers and herbs, as well as some fruits, need a chill period to germinate. Wild fruits accomplish this naturally; the fruit falls to the ground, decomposes, gets covered by leaves, and the seeds sit all winter and germinate in the spring (and wildflowers behave similarly). However, if you’re starting your own seeds indoors (as many gardeners do), you may need to cold-stratify your seeds in order for them to germinate.
Cold stratification is super simple and easy, but many gardeners don’t realize they need to do it.
First of all, let’s define cold stratification, and why it’s important. According to Melissa over at the Pioneering Today podcast:
Cold stratification is putting seeds into a dormancy state with temperatures below 40° Fahrenheit for a specific period of time in order to improve the germination rate (the number of seeds that will sprout).
This needs to be done with specific perennial and biennial herbs and flowers when trying to grow them from seed indoors.
In nature, these seeds won’t sprout without the cold period because if they did sprout early (right before winter) then they would die, so this cold period which signifies winter, allows them to sprout in the spring when temps warm up without the danger of winter freezes killing them just as they’ve sprouted.
So, let’s get started! This helpful video covers which plants need cold stratification, which ones don’t, and how to do it: