Are the seeds hard? I have dollar store sunflowers (Mammoth Sunflower, probably) and the heads are drooping over. I checked this week and the seeds were white, but they will change color. Depending on the sunflower, imho, not all of them develop with hulls. When I save seeds I don't save the ones without hulls--I toss those in the trash. There always seem to be some that are flat with no 'meat' in them. It may have to do with the pollination process of the plant. It takes a long time for the seeds to develop fully. If you get immature seeds they won't grow next year because they won't germinate. On the other hand, don't wait until they fall out on the ground. Some people tie a paper bag around the head to catch the seeds or use other such ideas (you can Google that). Just keep an eye on it and you'll have lots of seed to trade and plant next year. Oh, and be sure to dry out the seeds completely or leave in a place that gets air. Paper envelopes work well. You might not think they have moisture, but a little moisture can cause them to mold before spring which isn't good, especially if you save seeds in plastic baggies. Heidi (I'm already planning my sunflowers for next year. Isn't it exciting?!)