As a general rule, deadhead sunflowers when they start to fade or when they are damaged and no longer attractive, before they produce seeds. ... If you want to save the sunflower seeds that form in the center of the flower heads, then don't deadhead the flowers until their backs start to turn yellow.

Should I cut the dead flowers off my sunflower?

If you want a longer flowering season, plan to deadhead sunflowers. Cutting back the spent blooms encourages new flower shoots to grow. If you'd prefer to have sunflower seeds for roasting or future planting, do not cut the spent sunflower heads until they are dry and brown.

How do you keep sunflowers blooming?

Keep them deadheaded until the end of the season. If you deadhead your sunflowers, they will keep pumping out new blossoms in their will to create seeds and more sunflowers. Don't cut the stalk way back, the next sunflower often forms just inches from the place you deadheaded.