Ridges in leaves

Too much nitrogen for a start and the ridges can be an early sign of a magnesium deficiency.

Hi, even after 10 years growing, diagnosing issues is crazy. First we rule out the basics, ph, lights, temp/humidity, airflow through plant. Check runoff, I've seen conflicting info on this so if mine doesn't have bizarre readings I leave that alone. I've read pH can show 1 point lower then actual, say 5.2ph runoff soil is 6.2. Not positive but all the time I've checked mine it's in the 5's but I feed 6.2-6.8. If TDS are over 2000 I would flush. It would help to see a pic of whole plant. Most nutrient issues have varying effects on different parts, higher and lower, new and old growth. The only thing may be Phosphorus which is essential in flower. Deficiency shows dark green leaves on whole plant lower may be yellow. As mentioned in other comment about phosphorus, toxicity though would have curled down edges and tips, even wilting and I don't see that. Good luck

could be climate realted - high temps or low rh. Or, is a fan pointed directly in this area? Older leaves, especiially if shielded, do age, but they are still useful. If isolated or only on older leaves, i wouldn't overreact. just keep an eye on it.