Purple Punch 2

Looks to be a magnesium deficiency, A light green or yellow coloring will begin to show on the veins and edges of the lower & older leaves – this is one of the classic signs of cannabis magnesium deficiency. You may also see red stems. Magnesium is a mobile nutrient, which means that the plant can move it from old leaves to new leaves The edges of the leaves may become yellow or bright green and may start feeling crispy to the touch. This crispiness around the edges is different from nutrient burn, which does not lighten the margins inside the leaves. Hope that helps