Chive seeds will develop after the flowers are pollinated. The flower head will dry to a pale tan color, and the stem will start to turn brown: At that point, the seeds inside should be ready to harvest. Snip off the dried flower heads (you might place a white plate or bowl underneath to catch any seeds that might fall), place them in a paper bag, and shake (alternatively, you can rub the flower head gently between your fingers over a bowl). The black seeds will release and you can collect them. Be sure to separate them from the chaff (the rest of the flower head pieces). Store in an airtight container in a cool, dry, dark place; the seeds may last 1 to 2 years. Chive varieties may cross pollinate, so you might not get exactly the same offspring as the parent plant if other varieties are about.
Chive seeds will develop after the flowers are pollinated. The flower head will dry to a pale tan color, and the stem will start to turn brown: At that point, the seeds inside should be ready to harvest. Snip off the dried flower heads (you might place a white plate or bowl underneath to catch any seeds that might fall), place them in a paper bag, and shake (alternatively, you can rub the flower head gently between your fingers over a bowl). The black seeds will release and you can collect them. Be sure to separate them from the chaff (the rest of the flower head pieces). Store in an airtight container in a cool, dry, dark place; the seeds may last 1 to 2 years. Chive varieties may cross pollinate, so you might not get exactly the same offspring as the parent plant if other varieties are about.