I'll join UnknownClown in welcoming you to the forums. Where is your VFT? In a terrarium? Mold is usually a sign of lack of air circulation and warm temps. If you have your VFT enclosed in something, you might want to leave some kind crack (lid, cover) to allow more air in. VFTs don't require real high humidity so you can grow it uncovered (but kept wet in a tray of water).