Any idea what could be causing this? At first, I thought maybe it was grow light burn but am now highly doubting that is the case. I’ve used the same grow light for about 3 years now and haven’t had an issue before. Yellowing is effecting (mostly) the bottom half of tree and has remained on the tips of the leaves so far. Noticed this maybe 2 weeks ago, doesn’t seem to have gotten worse.

I’m in the Chicago suburbs, plant has been inside all year in southern facing window, potted in 511 mix that is about 2 years old now? I use dyna-gro 9-3-6 but have been very inconsistent with it…. The reasoning behind that is because I may(definitely) have way over fertilized about 9 months ago. I planned on repotting in new 511 but never got around to it plus it seemed to recover from me pretty much poisoning it so I let it be. After I accidentally drowned it in fertilizer, I did flush the soil in the shower at each watering- maybe 3 times after & have since pretty much let it be. I can’t remember if or when I fertilized again after that, I’m sure I have but it’s been a while now.

I have fertilized again with the last 2 waterings because of the yellowing and the lemons that are still on the tree. I’m just at a bit of a loss because I have no idea where my nutrient levels could possibly be at now. I may still have too much of something but lacking other things. I guess my tree is finally trying to scream the answer at me but I cannot figure out what it’s saying! Can anyone translate please?