Sunflowers are fun to grow and great to eat. That is, if you can beat the birds and squirrels to the seeds.
Protect your harvest by covering the flowers with a paper bag or cheesecloth as soon as the seeds begin to form.
Harvest the seeds when the back of the flower head is banana yellow or brown and most of the yellow petals are dry.
This is also when you can easily rub the fluffy covering off the plump seeds that have developed their characteristic gray stripes.
Eat them fresh, roast a few, or hang the harvested flowerheads upside down in a warm dry location to dry. Remove the seeds by rubbing your hand over the face of the flower.
Store the seeds in a cool dry place. Shelled sunflower seeds can last several months or longer if placed in an airtight container in the fridge or freezer.
A bit more information: Roasting tips? Capture your success by taking a few photos of these giant plants before harvesting. Then make a few into birdfeeders. Punch 4 evenly spaced holes in the flowerhead with a screwdriver. Run twine or colorful yarn through the holes to create a hanger.