could be either potassium, zinc, or sulfur.

marijuana bible suggests those . . . look at your nutes. . those are the ones showing yellowing at the edges/ brighter green leaves followed by the dark brown/red edges that are curled and look burnt. You might as well clip those brown parts off they be dead Im sure. :P

but the curling leaves suggest the fertilizer is too strong, or the plant is sensitive to it . . .

What is your pH right now? remember... 6.0-6.5 = happy pot plant imp: