I've got a few giant sunflowers that are hanging pretty low. I peeled off a few seeds around the outside just to see what they looked like and they look pretty big. They're fairly light though, not dark like the seeds I planted or the seeds you buy in the store, and the seed inside the shell was really flat and almost gooey.
How much longer do I have to go and when will I know they're ready to pick. I'd like to roast them. Also, should I knock off the petals on the flower (does this help them not rot)?