theres some white mold in the soil in some of the pots and some of the leaves have started turning yellow. can somebody tell me what is causing this?
Any number of things, and the two may not be related. Mold grows in damp/humid conditions, so you could be over-watering and/or leaves are trapping moisture on top of the soil and/or your ambient humidity is too high. Good ventilation is the best way to control humidity. As for yellowing leaves, that could also be from overwatering but further could be a nute or pH problem.