Hi,
These seed do benefit from stratification. A couple weeks in
the cold (between freezing and 40~f, 5~C) is good for most
Sarracenia and D.rotundifolia. Perhaps a bit longer for the Drosera
since it is a more northern plant. I usaully go with six weeks for
Sarrs but lately I've noticed that even a one or two weeks at those
temps are good for most of them.
Dave Evans