Yes, sunflower seeds from bird feeders can be grown into plants but at this time of year the new seedlings will be killed off the next time there is a frost. You may want to dig up the seedling and pot them up so you can bring them indoors on cold nights and keep them protected on cold days next to the house. Growing volunteer seeds can be thought of as a fun hobby but if you want great sunflowers for your garden I suggest you purchase fresh seeds to plant indoors following instructions on the package. The seeds from the feeder are most likely not the hybrid or most beautiful varieties. A package of fresh seeds is inexpensive and more likely to grow what you think of as classic garden sunflowers - plus there are so many new and more colorful sunflowers to grow from seed. Just remember that sunflowers are annuals so they cannot handle frost. Keep growing, Marianne Binetti