You can save those seeds....I often save from plants in the middle of winter....because I haven't got the time to do them all in Spring. It's quite possible that the seeds have received some strat....being snowed on, rained on...and that moisture adhereing to the seeds for some time. However, it may not alway be sufficient.

Do you know what variety aster you have? A good many don't need stratification at all and will germinate with or without it.

T

These asters are a perennial short bushy variety. About 15-18 inches tall and they're in shades of purple blue and pink. Kind of bushy and full looking. Don't know exact variety though...