hello I tried cold stratification for many seeds, including Echinacea purpurea! I discovered with time that its best to sow a small amount of seeds in damp coarse sand perhaps 3/4 sand 1/4 the seeds kept in a covered plastic container such as a Philadelphia cream cheese pot and let it stand in the refrigerator from four to 8 weeks according to the species requirement and then "sow" the entire mix in lines in a tray filled with ordinary seed compost. By doing so, one can watch emergence along the lines and avoid confusion with weeds that can sprout anywhere. Getting seeds to try new species is quite a difficult venture this far south so they are great treasures when I get hold of some. I partition my seeds so that I can give them a try during few differing times. Unless I start off from seeds, I have no other choice since the cultivars are not in the gardening trade nearby. I prefer controlled conditions so later the trays are placed in a cool greenhouse. They only come outside to be transplanted in the follwing spring. I'm fortunate to have a small greenhouse that allows me enough room for all my experimental trial vegetables as well as for the rare ornamentals that I am able to lay hands on. Warm regards Arturo