Beginner Gardening: Dwarf Meyer lemon tree with lightly mottled leaves, 1 by CapeCodGardener

CapeCodGardener wrote:
Hi! I have a dwarf improved Meyer lemon tree, about 3 ft. tall, which I acquired in December--never grown one before. It lives inside under a gro-light in my kitchen. The air is somewhat dry because of our house-heat. I haven't fertilized it yet, since this is a dormant period for citrus (?) The leaves are beginning to appear lightly mottled (see photo). It hasn't dropped many leaves, and it has lots of blossoms on it, but I don't like the mottling. I don't see scale or other pests. Is this mottling happening because it needs fertilizer? If so, what sort is best? Should I do a foliar feed?
AS you can see, I'm a beginner at this.
Thanks!