How do you know when the sunflower head is ripe?
The best way is to test the seeds by taste and appearance. If
the inside of the seed looks green or empty then it is not ripe.
The seeds ripen from the outside of the head to the center. The
petals will be shriveled, the head down-turned and yellow on the
back. Sometimes the seeds - especially those in the middle - do not
ever fill properly. When ripe, it is easier to rub the seed loose
from the head. The seed color usually darkens also.