I'm new to the terrarium world and having mixed success with my first few creations. Hoping to get some advice from all the terrarium veterans out there. Mould and limp plants are my main problems. I've tried open and closed containers and had those problems in both. I'm using quality potting mix on top of small stones or scoria and charcoal. Fittonias are my main plant of choice (love 'em!). I've been giving them a good spray when first planted to get them going and clean the inevitable debris off the glass. Is my initial watering maybe too much? Any help would be very gratefully appreciated.