hey there
@420pete , what's going on is that the plant did her first vegetation stretch and canabalised itself looking for nutrients, specifically it's looking for N and Mg , that's Nitrogen and magnesium, you can tell from the yellowing in the bottom leaves (N deficiency) and the yellowing between the veins of the leaves (Magnesium deficiency), this happens all the time basically because the cannabis plant eats more magnesium than your average flower. The best thing you can do is pick up a cal-mag supplement they usually have nitrogen in them anyway. Use it as a feed and use it as a foliar spray aswell (6ml / L on the spray) if you spray it on once a day the plant should recover in 5 or 6 days no problem. Hope this helps brother ! 🚀