Tomatoes & Peppers: okay, the next affliction: bluish or purple leaves, 1 by 6aseeder

6aseeder wrote:
actually, my tomatoes are doing smashingly this year but i do have this strange condition on one plant. ( it is a purple cherokee.) this plant is in a 5-gal bucket, treated identically to other nearby plants. the leaf perimeters are bluish or purple. the leaves seem to be folding or turning over slightly. otherwise the plant looks great: growing nicely, blossoming, a few good-sized tomatoes.

the last photo definitely looks like a deficiency to me, but i am not sure what of. i generally feed a flowering fertilizer (higher middle number).