This is sure to be the strangest thing I see all day. I also don't think it will work. It seems to me that when the gunpowder ignites it will burn all the seeds and the force will break them all apart.
A lot of the seeds might get wrecked, depending on the type of seed. But the wadding would prevent any heat damage I'd think. I'll get some peony seeds and try it out. Shooting them at some hard soil and finding a few seeds to see if they still germinate should be adequate.
I'll have results after the snow melts. I'm writing this on a sticky note right now so I don't forget.