seed stratification

What exactly is seed stratification and how do you know if a certain seed needs it?

Exposing a seed to a cold period to break dormancy to aid in germination.It can be done by exposing the seeds to cold outside as in winter sowing or keeping seeds in the fridge for a length of time.Alot of perennials require this treatment.Annuals usually don't.You will have to look up seed germination requirements on the the seed you are trying to grow.If you buy seeds the packet will tell you.If you plan to winter sow,you are covered.If you plan to grow indoors store your seeds in the fridge till you are ready to grow.Edge

Just a note of clarification. Stratification needs to be done with moist cold. Merely storing the seeds in the fridge is not enough. If I only have a small amount of seeds to be stratified, I will sow them in moistened media and then refrigerate the pot for the required time. You can also put your seeds on a moist paper towel insert in a ziplock bag and refrigerate. If time is a constraint, you can often get adequate germination by cutting the stratification time in half, but if you have the time, stratify for the entire length recommended. Some seeds need a double stratification with cold/warm and then cold temps again before they germinate. Actual temperature isn't as important as the length of time. Usually a temp around 40 F is adequate. Do not put seeds into the freezer for stratification.

thnx

How long should I do it for

Length of stratification is entirely dependent on the Genus/specie. Most N. American natives need 60 to 90 days although less time is sometimes adequate. Tell us what you are trying to germinate and someone here will be able tell you what is recommended and what has worked for them.

Pawpaw I got some from a wild tree when out hunting

Pawpaw needs between 90 and 120 days of stratification. When pawpaw germinates, it actually puts down a root up to 10 inches long before anything emerges from the soil. They take from 4-8 years to begin fruiting and you need two plants for pollination. If you google "pawpaw seed germination" you can find some sites that list very good information on their growth. If you are looking for pawpaw trees and don't necessarily want to grow them from seed, Oikos Tree Crops out of Michigan offers some for sale - www.oikostreecrops.com

Thanks