In article ,
K wrote:

Dwayne writes
Hi. I have never tried to start them inside, but I would think they need
some cold hours before they will sprout, almost everything else does.

Only things which naturally grow in a climate where there is a cold
period!

I wouldn't have thought this applied to peaches, but what would be
helpful would be getting inside the stones. This is probably why Dwayne
finds they come up in spring - it may not be the cold per se, but the
fact that the stones break open during the winter, allowing water to
penetrate to the seed inside.

I think thats right. The stones take some time to break down
and then open. But the dry storage period in the stone is likely
to be important too. Cracking fresh stones might not help.
There might also be an inhibitor which needs to be washed out.

http://www.theseedsite.co.uk/normdeno.html