Unless of course you want plenty of free seeds for next year. In that case at the very end of your growing season , take the flower heads that have completely dried on the plant , remove them , grab what used to be the flower petals and pull them away from the dried husk . You should now have a hand full of seeds . Please note not all dried flower heads will produce seeds but a fair number will, you willl see the difference. Keep in a dry place till spring , drizzle on the ground where you want then , cover with a light coating of soil water , stand back and let Mother Nature do the rest.
Unless of course you want plenty of free seeds for next year. In that case at the very end of your growing season , take the flower heads that have completely dried on the plant , remove them , grab what used to be the flower petals and pull them away from the dried husk . You should now have a hand full of seeds . Please note not all dried flower heads will produce seeds but a fair number will, you willl see the difference. Keep in a dry place till spring , drizzle on the ground where you want then , cover with a light coating of soil water , stand back and let Mother Nature do the rest.