Confused on spike moss care?

So I noticed a few threads about spike moss care and I see well drained yet humid... How is that accomplished? I would think it couldn't be humid if is well drained. This is my 4th attempt of keeping spike moss alive it always seems to melt. It doesn't turn brown just kind of darker green then melts slowly into dirt. I keep Crested geckos not frogs but they seem to like either high or low humidity right now i have a girl laying eggs in dirt so im keeping one tank very moist right now (no moss in there). Other 2 tanks I can play with humidity and moist or dry dirt. I mist tanks 2 times a day once in morning and once at night. Any tips would be great as I love the spike mosses color and love idea of my tank being all green. Using florescent coil 5.0 repti glo lights. Turn on at 9am and off at 10pm. Soil is a cocoanut husk broken down.

Thanks for any help.