Buy the 2015 Old Farmer's Almanac!
Reporting
It sounds like the problemIt sounds like the problem may be your soil. Sunflowers are heavy feeders. If you try again, work some slow release granular fertilizer into the soil.

2015 Special Edition Garden GuideCooking Fresh with The Old Farmer's AlmanacThe Almanac Monthly Digital MagazineWhat the heck is a Garden Hod?