Hello all. I am new here. We just bought two weeks ago a Ficus Benjamina . About 5 feet tall. We notice everyday it drops about 3 to 5 leaves . Some are yellow , some are still green. I’ve heard they like humidity so I have a humidifier next to it. What humidity should they have ? I also noticed , I watered about six days ago , and the soil is still moist and looks like maybe mold may be forming on top the soil ? Any help would be greatly appreciated. Thanks.