- Harvest the seeds only after the bloom is fully mature: The flower's petals will have dried and begun to fall. The back of the flower will be dry and yellow to brown in color, and the seeds will be visible. They should be plump and black and white in color. The seeds ripen unevenly, however -- those near the edge ripen before those in the center.
- Birds provide another indication that seeds are ready to be harvested. Once the birds notice the seeds are ripe for plucking, they may beat humans to the crop. For this reason, it is often recommended that the seeds are harvested prior to maturation. There are a couple of ways to save your seed crop from its natural consumers.
- Cut the flower head off before it begins to fully dry, leaving a long enough piece of stalk to tie a string to. Tie the stalk and hang in a room that is dry and well-ventilated. It is a good idea to cover the flower head with netting in order to catch any seeds as they fall. Be certain to take precautions against critters that might find their way to the blossom through the netting. Mice love sunflower seeds.
- Allow the blossoms to dry on the stalks but cover them with paper bags that are tied about the stalk just before fully ripened. The bags will need to be replaced if they get wet; a moist environment will cause mold. When they are nearly all ripe, cut the stalk just below the head and shake the contents into the bag. Use your fingers to harvest the remaining seed stragglers.
