Those oranges could be outside in the summertime, too btw. They look pretty good, nice color and big leaves. But is that hard water deposit, the white spots on the leaves? This could be what's holding them back on you - if the pH of your water is too high the plants can't make use of the nutrients as readily.
You should clean the leaves off so the deposits don't clog the stoma and they also block the light getting to the leaves. Then, from now on when you water, add a few drops of vinegar to it first. The amount is about a tablespoon of plain, white vinegar per gallon. Citrus plants shouldn't be let to dry out. They like regular moisture as long as there is good drainage.
