Yeah, I don't use manure, except when it is in compost, since all my trees are in containers. Knowing they are heavy feeders I try to load them up in the summer, but I must have gotten behind the power curve this year. My tangor is doing awesome and never drops leaves, and makes yummy fruit. Sure wish the others would follow her lead!
My potting soil is about 1/3 perlite and drains really well, and I keep them relatively dry during the winter. In addition to hitting them with fertilizer, would more light help? They are in the sunniest part of my greenhouse but it is still 50% shade, so I could put them under lights if that would help.
Carolyn