Er, so what does that make us with 9 of them?
Growing from seed is not really worth the effort. Most of the time the flower quality of seed grown ones is very poor compared to the named varieties on sale. Here they self seed all over the place and we have to weed them out rather often, before they get big.
If you really must, then the time to collect and sow the seed is when the birds start stripping them off the stalks, say from now on?