I was growing my live sphagnum moss in two terrariums but noticed white patches appearing in both containers. Fearing that they could be a fungus, which seemed to be spreading, I decided to open up the containers to improve the air circulation instead.
Anyway, I am positive that the sphagnum mosses were growing because the threads were elongating. It's amazing how they can just grow without any medium. I just added some to my carnivorous plants terrarium and hopefully, it would provide a green ground cover for the plants in time to come.