AaronT· Premium Member
It sounds like you've got some surface algae or fungus growing on top of your soil. The soil should be very wet, but the water does not need to be visible on top. Many of us use pots filled with substrate that are set in water that is about half the height of the pot. The substrate stays wet enough through high humidity levels and capillary action and the chance for fungus and algae to rot out the plants is reduced.