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Tuesday, June 16, 2009

Q and A: Are moss terrariums ridiculously easy to care for?

Thanks to Molly for a great conversation starter regarding terrariums.
I always see vibrant green moss terrariums on etsy which are advertised as being ridiculously easy to care for etc etc. After contacting the sellers, I learned that they actually grow the moss themselves.
I know moss thrives in humid, moist conditions, and the seller lists the terrarium as being extremely low maintenance and easy to care for, but in my experience, open-air moss requires almost daily misting. Is this person just confused about the nature of these terrariums?

Terrariums can be extremely easy to care for if they are a balanced and complete system. If there is a proper water cycle and enough air circulation- an ecosystem can thrive even in a completely sealed system. When a terrarium reaches a degree of "self-sufficiency" it can be extremely easy to care for- and may need water and a quarter-turn in the sunlight only once every few months or so. However- if moss exhibits signs of dehydration or disease the system can need careful water, management and maintenance.

A healthy terrarium requires proper moisture levels- which an open container may not provide. If a terrarium container is mostly open- it would take constant humidity or moisture to keep most mosses alive. This is most easily achieved by keeping a lid on a brandy-sniffer or fishbowl shaped terrarium. A lid can be a fitted top or even something akin to a dinner plate or a piece of plexiglass.

Sphagnum or peat moss (pictured above) as available in most craft stores- as a dried but live moss. You may have seen this dried moss stuffed on top of silk plant arrangements or worse- spray painted green and advertised as "dried moss" in a terrarium. However if given proper lighting and water this craft moss will come "back to life" and will grow green and begin sprouting. You can propagate this moss yourself at home by misting it and keeping it in an incubation terrarium. If it is given a chance to really thrive- this plant becomes the almost grassy-looking moss you see in many terrariums for sale. It just takes a little patience, some creativity and some insight into what moss requires for optimum growing conditions.

Often this means high acidity, constant moisture, some degree of air circulation and a somewhat enclosed system to protect the moss from insects, mold or rotting.

Tips and How-to guides at the Fern and Mossery


  1. I too love ferns and moss. We're having an extremely wet spell in Virginia and my moss and ferns are thriving. Wish I had more moss and less grass to cut. I will enjoy reading your older posts!

  2. hey there,
    just happened across your blog -- lovely!
    i was wondering if you could offer any more details on how to revive dried sphagnum moss? and how would i know if what i have is even capable of regeneration?

    thanks, and i'm excited to keep reading here. :)

  3. Hello there!
    I am also a fern and moss fanatic and I own a flower shop in BC Canada and am doing a big display on terrariums. I am having a hard time finding the glass hanging terrarium orbs. Do you sell them wholesale or do you know who does?
    Thanks so much in advance for any tips: squamishflorist@gmail.com

    1. Alanna...Did you ever find a good supplier?

    2. They are on sale at west elm right now for $10!!

  4. Hi Alanna,

    Thanks for your question. People seem to like the prices of hanging vases from CB2 (http://www.cb2.com/search.aspx?query=hanging) but I can't personally vouch for them as I have never actually purchased or handled these ones.

    Good luck!


  5. I make hanging glass terrariums. . . You can see them at http://www.etsy.com/people/ManyMinis?ref=si_pr
    Please let me know if you have any questions or are looking for custom shapes or sizes. Since I handblow all the globes myself I can do custom terrariums for you.

    1. Beautiful glass vessels Melissa! Thanks for sharing.

  6. Good morning - we could really use your advice as we're having just a dickens of a time with our terrariums. Some are open, others closed, some with ferns, some are just moss, some "wild" from the yard and some revived... none are doing quite well. Ferns are loosing leaves or turning black. Mosses are browning or yellowing. & the wild ginger, oh, I can't bare to discuss their sad plight, they were so pretty. Just can't seem to pin-point why.
    The latest theories are:
    a) our house doesn't get much light as the southern exposure faces dense woods and the windows are east and west facing... so we don't put them against the window or they could fry in the direct light, but elsewhere in the house isn't enough? ... & yet a boring philodendren on top of the kitchen hutch is having a hey-day in the shadows. To test this theory I've just taken two "controls" into work where I think the large glass windows will provide more light, time will tell.
    b) we like our AC temp set cooler than moss or ferns care for (75-77)?
    We have a few posts here - http://nestingranch.blogspot.com/ - if your expert eye has any pointers, would greatly appreciate it.

    1. Hi Nesting Ranch! I looked through the photos on your blog and I can definitely say I have had terrariums start looking as poorly as many of yours started to look. It is a tricky balance between finding the right plant, for the right terrarium vessel, and then striking a balance with sunlight and water levels. The truth is that I have planted and re-planted many of my terrarium vessels before I found the right balance that could sustain itself.

      1.) I see that some of the terrariums are lidded and some were not but you had some plexi covering the openings. That is good- you can't have them covered too often but you also cannot have them open to the air all the time. It takes some experience with "settled" terrariums to learn to watch the moisture on the sides as a gauge for how frequently to cover/uncover the lids. 2.) It appears you used a soil mixed with peat? I use soil mixed with sand to ensure that I can water frequently and have it drain through the soil quickly. As the environment is so small and enclosed I do what I can to make sure roots aren't standing in overly dry soil or damp soil. 3.) It looks like you placed large swatches of moss directly on top of the soil in some of your terrariums rather than splitting it into smaller chunks. I find that tearing the moss into smaller parts (after washing it and often after having it in quarantine to confirm its health) and slightly planting the torn pieces into the soil help it "take" better. 4.) Your unhappy fern photos are a sad casualty of terrarium-keeping. Some ferns just can't handle the conditions. I would encourage you to experiment with different varieties and if you spend money or have a special fern to use in the future - you may want to divide it into smaller, self-sufficient plants before trying one out in a terrarium to see if it takes.

      I'm going to modify this reply into a full blog-post this week so I can add links to some of the other resources on my site. May I repost some of your photos and a version of your original questions?

  7. I have a moss garden in an unused stone mortar bowl. I'm in the northeast. The moss garden sits in the shade, outside, year-round. I rarely water it, but moss grows in the winter, even though snow and ice cover it, and hangs on in the summer. It has its cycles. But I've never had it dry out. The moss bowl is 7 years old.

  8. I just found this: http://www.mossandstonegardens.com/blog/one-tall-dish-baby/ I think the needs of mosses are detailed quite well. I hope this helps.

    1. What a great resource. The note about not leaving moss in a covered cloche or glass vessel is very important. Moss needs air circulation to thrive.

  9. This post is misleading at best.
    I use both dried Sphagnum and living Sphagnum to grow Carnivorous plants and Orchids and to follow your directions is a prescription for heart break and disaster.
    First it seams you are conflating two different types of moss. The moss sold in craft stores "spray painted green" is sheet moss and is a product of forests and will never grow and will simply mold and decay creating problems along the way.
    Dried Sphagnum is a product of very acidic bogs and is usually sold by nurseries dried and in bales, such as that from Mosser Lee in Wi. or the high quality New Zealand Sphagnum currently in vogue among orchids and Carnivorous plant growers. If you are being sold Sphagnum as "dried but living moss" you are being taken advantage of. Dried sphagnum is not living and is in fact dead. Sphagnum grows in mats growing on the surface of bogs in a very acidic environment. Only the top layer of Sphagnum is alive and the many ancient layers beneath are what is harvested as Peat or Peat Moss.
    The dormant spores in dried Sphagnum can be very carefully coaxed to grow given the right conditions, and a terrarium just doesn't provide the right conditions. You can use a ziplock bag, a glass jar or any number of clear containers to coax it to grow. Sphagnum needs rain water to grow, tap water has too many additives and is in almost all cases too hard to grow Sphagnum. Sphagnum prefers good bright light and lo temperatures both summer and winter (under 70 degrees is best). If the conditions are not right it will either not grow or will die quickly. Sphagnum requires an environment that is far to wet for most terrariums. It will grow without any soil simply in a ziplock in a bright cold winter window as long as the water does not stagnate, but slowly. It requires a bog garden where the water does not stagnate to grow. In a bog garden where the substrate is mostly Peat Moss and Pearlite at a 50/50 ratio,and continual moisture supplied from rain water. Sphagnum is extremely sensitive to fertilizers and will die with minuscule doses. We often plant certain bog orchids and carnivorous plants right into living Sphagnum as they grow in the wild.
    Sphagnum will never grow inside a terrarium, the wet conditions it needs would kill all but the bog plants that grow in association with it and drier and warmer conditions would kill the Sphagnum.
    Sphagnum is great for growing in a bog garden as I described and even in a water garden that provides the it with the right conditions. For a terrarium a better choice would be woodland mosses, bit even these can be difficult to keep growing if the conditions aren't exactly right. A good substitute for mosses in terrariums and less difficult to care for would be Irish Moss or Scotch Moss( both are not mosses and are less demanding in their requirements). With out providing the exacting conditions for mosses the grower will be disappointed.

  10. I've used a couple of different things to 'solve' the open vs closed issue. I've found that a 'typical' terrarium needs to be closed most of the time. Moss in particular that I've grown does indeed need to be misted occasionally, and dries out fast if it's left open to the air; esp if in a sunny area. I generally leave container open for an hour or less per day, and closed the rest of the time. I've used old glass coffeepots with lids since this allows for just a bit of air to come inside, and doesn't require you to take off an entire lid. I've also used a glass globe bowl, and happened to find an old teapot lid that fit perfectly. Things like this are nice because the lid is plastic and I don't have to worry about a glass lid that could get broken when removed or cleaned. You can find a LOT of these kinds of things much cheaper at places like goodwill or salvation army shops. I've found things to use also at my local Habitat for Humanity store. Lastly, just a little FYI: there are actually over 22,000 species of moss worldwide, and many plants labeled as "moss" are not true mosses.
    I'd also like to recommend a book "Gathering Moss: A Natural and Cultural History of Mosses" by Robin Wall Kimmerer, who is a Native American botanist. Part cultural history, part botany, part nature spirituality, and written in a very 'storyteller' kind of way. It is a joy to read, and you also learn a lot !


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