Petunias- I've always used the wintersowing method- i.e. outside in milk jugs- but I don't sow them until spring or close to spring. I generally have good germination, including with seeds that are a few years old. But I do think the pelleted ones don't do as well when they're more than a year old two old. They might still sprout, but percentage seems to decrease or germination delayed. That's just personal opinion/ experience.I've wondered if the clay coating hardens or otherwise becomes difficult.
OTOH, I've been using the same batch of pelleted alyssum for about 3 or 4 years, and saw no increased resistance to germination as of last year. Maybe it depends on the genus or cultivar, or the material and amount of clay mix used to form the pellet???
The problem is, with WSowing, the weather can have a big effect, and it changes so much from year to year...Last year was extremely hot and dry, the year before unusually cold and wet. That makes it harder to draw conclusions.
Karen
