Chris, incarvilleas are generally one of the easiest genera from seed. Just sow by sprinkling the seed on a smallish pot (regular seed or potting mix) and cover with a layer of fine grit about .5 of a cm deep. Water well then keep cool until germination starts which should be in 7-21 days or perhaps a little more if the seed is not fresh. The seedlings should be quite hardy with you but if in doubt, keep frost free until the spring and second leaves are growing on well. No problems!
