Lemon plants stopped growing?

I am growing lemon plants indoors. They get great light and the right temperatures. They were growing quite fast, but stopped growing about a week ago, at about 3 inches tall. They still look very healthy though. When the soil is dry, there are a few white parts on the surface... is this mold? How do I save them?

Lemon plants stopped growing?
perfect thing to do is find a shady and sunny spot in your backyard , front yard , or garden replant your plant whith moist , organic , and dark rich soil , water it everyday , check the soil , and fertelize the plant with compost by , maybe yousing a jar or basket to throw in fruit , vegetable , meat or fish puree from organic products even bread , that's what i do and it works better than chemiclas that you use for planting to make your plants bigger , my garden is huge and your lemon tree wil be healthy and huge too , your lemon tree needs some Oxygen that's why , and the white stuff i don't think are mold but it could be a posibilty i don't think there any eggs either they mite be stones that come mixed in with the soil ! well hope i help , nothing to worry your plant will grow beautifully ! Good luck !