What would you want to grow directly under your feeder? I think if you cleaned up all the hulls, amended the soil and did not let the hulls accumulate you could grow just about anything you want provided the other conditions are good. There may be some plants highly sensitive to sunflower seeds but I don't know what they are, and likewise there may be plants that are immune to the effect of them. I have never seen a list of such plants, so it will be interesting to see if some people do have plants that do well under bird feeders using sunflower seeds. There is nothing growing in a small circles directly under my feeder, not sure how much is caused by the hulls and how much of that is caused by all the squirrels and birds constantly patrolling the area for stray seeds.