We went to the Washington rain forest in October. As a little reminder, we made terrariums around Christmas and they are still thriving. I only had to open the lid once after day two when I noticed there was too much water in there. I had to dry it out a bit.
The plan was to put real moss on the top layer, but that didn't work out so dead moss worked just fine. The other terrarium had a larger fern in it. I was able to break the first one up much easier. The one below looks more like the rain forest.
activated charcoal - in the aquarium isle