I have a spider plant. Some of the leaves appear variegated (photo 1) and some of the leaves do not (photo 2, maybe some of the leaves are lighter in the middle, but nothing like the stark green-white contrast on the leaves in photo 1). Both photos are from the same plant. Is this normal? Is it because of genetics or some other thing, like that I recently started giving the plants plant food?
Note that I also have two other spider plants; all three are parents/children of each other (I am not sure of which came from which). The other two appear much more like those in photo 2.