When I have a seed that resists or takes a long time to germinate, I
soak it/them in Lipton Tea for 12 hours which greatly reduces germination
time. I have used the technique with Parsley and Orchids. A twelve hour
soak will kill many garden seeds and I haven't determined soak time(s) for
anything but Parsley and Orchid.
I also haven't tried it with seeds that require cold treatment but I
suppose it should be tried.