I recently rooted a mini rose and planted it in a small terra cotta pot. it sits in my kitchen window with day and evening sun, and is showing out. it started as just a little green twig and now it has leaved out nicely and started a bud. when i water it, the pot grows a white fluffy layer that looks like mold. the part of the pot that faces the window fluffs up last. what do i do? this is the first rose i've ever had flourish in a pot.