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Watering Moss Terrariums
Reader Questions
Building a terrarium? Twelve species in stock, cleaned and pest checked for closed builds, from a quarter of a square foot. Sheet moss for the floor, cushion and mood moss as accents.
Dear Moss And Stone Gardens,
Hi! Let me just say, I’m a huge fan of your blog. Keep up the wonderful work!
Anyway, I have a question about tap water. I have three moss terrariums (all open) and I have been watering for a few weeks with tap water. The moss kept getting progressively browner because my tap water is apparently moderately ‘hard.’ But after some research, I’m starting to collect rainwater and I might even go buy some distilled water.However, will the moss that is already slightly brown bounce back from the damage once I start watering with rainwater/distilled, or should I harvest new moss?
Thanks in advance!
Lauren
Dear Lauren,
Short answer to your last question first: no, you almost certainly do not need to replace it. Brown moss is usually dormant rather than dead, and it greens up within minutes once the water is right. Give it a fortnight on rainwater before you write it off.
As for the rest, there are several factors that affect my advice: what species you are working with, and what you mean by brown.
If the species are pleurocarp, then chances of recovery in your terrarium are fair. If the species are acrocarps, to regenerate, they will need the help of Mother Nature. To do so, return to the earth for about three months.
If the color brown is dark brown, then too little light or too much moisture is the cause, if pale brown or tan you are likely to have too much light or stress from impurities in the water.
You may want to see the post Knowing your acrocarp from your pleurocarp to help determine which type you are dealing with.
Moss does keep indoors, but the build has to suit it. A closed terrarium holds humidity indefinitely and suits almost every species we supply; what fails is a sealed box that is never opened, or moss kept permanently soaking. Vent it, let the surface dry a little between waterings, and it will hold for years.
As for the water source, rainwater is best, then reverse osmosis, which removes the chemicals but leaves the trace elements. Distilled works. Untreated tap water is what browned yours: chlorine and hardness are both hard on moss. That is the same advice we give on terrarium moss.
Moss And Stone Gardens
Pending review by Olivia Milner, practitioner-scientist with a background in sustainability and education.