Then damp vermiculite, or perlite, damp kitchen paper or whatever (damp peat moss is not good if you want to separate the seeds after stratification because the seeds are dark too and hard to pick out) for 4 to 6 weeks. If you can't make up your mind do 5
I wouldn't bother going over 6, and for some 3 weeks or even less works. The time depends on the individual seed so you have to cater for the longer ones. Then move them to room temp for germination.