I did not know if I should break open the pits or not, so at first I didn't.
I let them sit in a damp baggie of soil all winter inside but nothing grew. This is the same, basically, as the wintersown: you take a baggie of damp potting soil, add the seeds, and seal it to keep it damp.
Because nothing grew I gently broke open the pits with a hammer and I planted the kernals that I did not break: I now have 4 sprouted seedsin pots on my back deck.
I have bought conservation grade American Plums, which are now growing well. Conservation grade peaches? Well, why not? I will plant these out, by and by. I meant to plat the sprouted plants directly into the ground, with flags to mark the spots, but life happened and there was no time for it. So they will spend a little time in pots first.
I am aware that fruittrees do not come true from seeds, but I am enjoying the seedling apples that I bought (they were intended as root stock). Some of the trees have good fruit, though not all of them do.
Once, sitting on the back steps waiting for the BBQ to get ready, i was eating a nectarine, and just tossed the stone into a patch of dirt between the cement and the fence. Next year, a seedling sprouted, and reached 3-4 feet. The next year, it was 5-6 feet with some branches that I never pruned. The following year, I ate the lone nectarine that grew from it! I could not believe it! The nectarine was not sweet, but in subsequent years, they (few) were. I probably could have bought a $40 tree at a nursery with less results!