I have a sweet pomegranate tree (I bought a 2-3 year old plant from here) that I bought about 9 months ago. I have it planted in a 12" diameter, 14" deep pot with drainage holes at the bottom that sits on a saucer. I planted it in Miracle-Gro Performance organic all-purpose container mix. It is lit by a 36W full-spectrum 95 CRI grow light that I keep on 24-7, since as far as I can tell pomegranate trees don't have photoperiodism, and need as much light as possible. My apartment is north-facing in Michigan, so the only way to give it more light would be to have more grow lights. I have supplied nitrogen fertilizer with fertilizer spikes recently about a month ago and they still there. Our municipal tap water has an alkaline pH of 9.5, so I have used ferti-lome soil acidifier plus iron (w/ iron, zinc, sulfur, magnesium, and copper), to help lower the pH. The last application was awhile ago. I recently measured the soil pH at 7.5, which I see as just a bit high. My understanding is that the ideal is around 6.5. Because my apartment was a little chilly over the winter, I used some heating pads and a temperature control (like the kind for germinating seeds) to maintain the soil at 75F, and I still have that system in place, because I think it should be helping.
For a fairly long while, the tree has had aphid problems, but I think I have finally exterminated them with a fairly aggressive use of pyrethrins in neem oil, since my first less-agressive treatments did not seem to be effective. I think this is likely contributing somewhat to the plant stress.
My tree has never looked as good as when it first arrived with large dark leaves. Currently, the leaves are small and light green, and many of the tips are brown and dead. Slightly older leaves often turn mostly yellow and then fall off. I examined the roots today and have included a picture of them. They seem fine but had not extended through the pot as much as I had thought they would. I have also included pictures of the brown tips and of some new growth.
Even though I have tried many different things, I have not been able to see any noticeable improvements over most of past 9 months I have had this tree. What am I missing or doing wrong?
