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I wish I could bring them home and have them grow like that all year but the moss only lasts like that for spring in specific conditions.

I guess it's the humidity

They seem to like a cooler temperature in the 40s to 50s with a dew mist once a day. I once tried to keep a rock like this at home but eventually after a couple weeks the moss dried out even though I misted it. I suspect it was too warm inside for it.