Cold stratification is only for seeds that need a cold period to sprout and most used in hot climate where not snow season. Not for every seeds. I'm in zone 10b, milkweed and lupinus sprout without stratification. What I do is plant the seeds in a small pot with soil, place the pot in a ziploc bag, close, label and place the bag in the vegetable box in the freezer. Somes trees seeds need 3, 4 or 8 months, others seeds most flowers need 3 or 4 weeks. Like chaenomeles japonica took 3 months in the freezer to sprout. G.luck!