I have a dwarf lemon tree. The leaves are turning light green, the veins are green, but the rest of the leaves are turning yellowish in color.
Lemon Tree Leaves
Certified GKH Gardening Expert
Healthy Lemon Tree leaves are reddish when they first appear, turn dark green below and then lighten as they mature.
Leaf yellowing can be caused by temperature fluctuations, watering issues and nutrition problems.
The links below will help you pinpoint the cause and how to correct.