So if any of you have followed my grow you'll know that recently I changed pots & lights. I also gave them a massive haircut and stripped them right back. Fan leafs are coming back but they look a bit yellow. Can't figure out if it's nitrogen or calmag deficiency Thoughts and opinions? Sent from my CLT-L09 using Grasscity Forum mobile app
Looks more like Nitrogen deficiency than Calcium. Nitrogen gives an even paling (yellowing) of the leaves at the bottom like yours are.
btw, how longs it been since the transplant? It could just be unhappy (ie. transplant shock) and need more time.
Try a floral feed of Epsom Salt, 1 tsp per gallon of r/o water then ph it to within the range that your medium requires. Then if it was a magnesium or sulfur problem you will see those lighter leaves turn greener within 24 hours! But I feel like its a magnesium deficiency because the plants leaves look overall healthy, but they are canoeing upward, (a true sign of a lack of magnesium), and many of the leaf edges have a romaine lettuce top ruffling going on, which to me point to the plant needing more magnesium.