My 6yr old lemon tree is overwintering in a frost free (unseated but bubble wrapped)greenhouse,but the leaves are not green and glossy but yellowy green. It was repotted two years ago and has given me lemons since, I have fed it with Citrus food (winter) as per instructions on jar. What’s the matter with it and what can I do.Any advice please.
I had the same problem with a orange tree I grew in a pot from a pip. Fed it with magnesium and replaced the top few inches with fresh John Innes. Had it for many years. Sadly I lost it a few years ago.