Can anyone point me in the direction of what this may be? Is it a deficiency or toxicity? Increased her feed then within a few days this appears, I accidentally let the soil get too dry before watering which I think has possibly caused lockout maybe
Based on what your saying and what I see I would lean towards the ph in the substrate has gotten out of range. So you would be correct on a lock out. You would have to measure the ph of the run off to know where it is at. Heavy feed can cause a ph to drop fast if the plant can't use it as fast as it gets it. So your run off ph can tell you where you are on feeding as well if you track it. Ph Going down too much feed. Ph Going up not enough feed. Then follow the correct ratios for NPK at the stages they are in. This is what I would check first.