hello all.

last year i grew some sunflowers for the birds to munch when they have gone to seed, however the seeds that have developed dont have a heart in then if you know what i mean (its just husk with nothing inside), do some varieties not form seeds?ive done some investigating and read that sunflowers which produce oilseed are the best for birds does anyone know some varieties that i can grow that produce this type of seed.

thanks