Introduction: The Basics of Closed Jar Terrariums

Picture of The Basics of Closed Jar Terrariums

I've been creating closed jar Terrariums for about a year.  It was something I wanted to learn and finally decided to give a try.  Since then I have picked up a lot of info about making Terrariums, and also teach workshops on making them.  The workshops give me motivation to learn more, hone my skills and work hard to get the best outcome for the groups that come through. 

This instructable will give you a guide to collecting and cultivating moss and making a closed jar Terrarium.  Make sure you read all of the notes on the images for extra info.

Step 1: Moss Gathering and Prep

Picture of Moss Gathering and Prep

Moss Gathering and Prep



*Plastic Bags
*Spray bottle
*Plastic Containers

When collecting moss to use in your closed Terrarium it is important to harvest the moss and cultivate it for approximately 2 weeks before putting the moss into your jar Terrarium. Cultivating it for two weeks lets you see what is does in closed environments. You can see how the moss will grow, weed out any mouldy spots that appear and see if the moss you have found is suitable for closed environments.

Finding Moss

We've had very wet weather in Brisbane recently, perfect for all the moss that has taken off over the last few years. I am pretty lucky that two yards near me have a good supply of moss along their front fence lines, so I often pick that. I also grab moss from other spots. We have a fair few different varieties of mosses in different spots. You can find moss in shady, moist spots, often near fence lines. It is very rarely under/around tree bases and any of the moss around the tree bases here is unsuitable for closed jar terrariums as it goes brown. Moss seems to enjoy some sun each day, so look for locations that enjoy just a little bit of sun.

The best way to find moss is go for a long and rambling walk with your eyes down, during or at the end of your rainy season. Take note of the moss patches in your area so you can come back to them. Even if the moss goes brown and looks dead you can bring it back to green quite quickly by harvesting and popping into containers.

I collect moss in clear freezer bags. I take the bags and a few sticks out with me and dig up clumps. It usually comes up in big clumps. The bags get full of a range of mosses from the area. When I get home I usually just dump it and come back to it sometime that day. No rush, it is perfectly fine in the bag for a day or two as long as you keep the bag closed.

Avoid moss that has gone to seed. When moss has gone to seed it will have little stalks with balls on the end. Do not collect this moss. It tends to go very brown, maybe even dead, and will not grow in a Terrarium. If you notice your moss grow little stalks pull it out and throw it in the garden.



Step 2: Preparing Moss

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Preparing Moss in Containers

When I put the moss into containers I mix up the types and try not to break up the clumps too much. It is better to have large clumps that I can break up when setting up a Jar rather than have to put in a bunch of small clumps. I leave the soil that came up with the moss on the moss.

I have found it is essential to use containers approx 5-7cms tall. The moss does go “off” in shallower or deeper containers. I will explain a bit about this when we get to making the Terrarium.

When you put it into a container you may need to spray it if it is dry. It is better to under spray than over spray. I usually say two sprays with the sprayer and see how it goes. If you have a look at my photos you can see the level of condensation on the walls of the containers. The trick is to not over water as you get more mould. If moss is water logged it often gives up. Underspraying means your moss looks dry and crunchy.

Once the moss is in the containers I put the lid on and check the moss every few days and pull out mouldy or brown patches.

If the moss in the containers grows mould throw the mouldy bits out. If it goes brown throw it in the garden, it will probably come back to life in the right space in the garden but is not suitable for a closed environment.

You can also plant healthy moss in suitable spots in the garden to get more to grow!


Step 3: Putting Together a Jar Terrarium

Picture of Putting Together a Jar Terrarium
 Putting Together a Jar Terrarium


*Glass Jar with a Lid
*Little Pebbles/gravel
*Activated Carbon/Charcoal

*a couple of paddlepop sticks (popsicle sticks?) are handy if you have a deep jar with a small hole.

These are the bare essentials. You really do need all of these. Here in Australia Activated Carbon is about $35 for 500grams, add shipping if you cannot source it locally. It sucks to have to pay that much but it is essential. The good news is that a 500gram bag will last you a really long time. To ease the blow you can always plan to make a few Terrariums or make them with a group of friends and split the bag between you.

Now that you have some good sturdy moss following my previous instructions you can put together your moss terrarium.



Step 4: Build Your Terrarium

Picture of Build Your Terrarium
 Build your Terrarium

1. Stones/pebbles/gravel
2. Charcoal
3. Netting
4. Moss and soil
5. Decorations and seeds

These are being built up in layers. The only layers you could mix together are the moss and soil and seeds.

For something a little different think about...

Add only a small patch or island of moss and use stones for the rest of the terrarium.

Make the ground undulating or sloped.

Add some seeds for some little plants in your terrarium

Add an animal (a plastic one)

Stones/gravel should be added to fill about 1/4 of the jar.
Charcoal/Carbon should be sprinkled on, about a teaspoon for a jar about 7cms diameter.
Netting, cut to size.  You don't want to see it from the side of the jar though.  You can give the jar a squirt of water onto the netting to prevent the soil falling through.
Soil, in a thin layer and to even out your moss height.   
Moss up your jar.  Add as little or much as you want.  I like to leave space under my animal if I am putting one in.
Add an animal and some seeds you've found if you'd like to grow some little seedlings.  The plants shouldn't grow very big.  I have found that they tend to grow to suit the closed environment they are in.


When your jar is done give it a squirt.  1-2 squirts at the end is usually enough.  If you think you've given it too much moisture you can take off the lid for a day or so.  It is really wet you can leave it in the sun, lid off, for a day.

When building a Terrarium they say the magic ratio is 1/3 filled and 2/3 space. I have found this to be about right. Terrariums with less or more space can grow okay, but I have found the 1/3 filled, 2/3 space ratio seems to work well. This probably has something to do with the amount of evaporation, air flow and how the moss feels in the environment.

Things to remember

There is the possibility that there will be eggs that may hatch in the soil or moss, if this happens pop the lid and let the little bugs out.

The soil and moss does have bacteria and miscroscopic animals, please wash hands after adding your moss.



Step 5: How to Display and Care for Your Terrarium.

Picture of How to Display and Care for Your Terrarium.
How to display and care for your Terrarium

Moss terrariums should be sealed and only opened every now and then. Reasons to open may be; mould growing (from excessive moisture), looking too moist (look at the soil under the moss, does it look really sloppy and wet?), watering in the hot months, bugs hatching, having a closer look at your plants and to show your good work off.

I have found that it is generally unnecessary to water them unless you can see your soil looking dry or the walls of the terrarium are not misting up. It may be necessary to give a light spritz mid summer depending on how things look, or mid winter if your climate has a dry winter.

Your moss terrarium grows best in a well lit area that has NO DIRECT SUNLIGHT hitting the jar as this will burn and cook your plants. Rotate the jar for even growth of moss.

In case of emergency

Moss Terrariums can die, or start to look pretty horrible. You can always throw out the Insides of the terrarium, wash your decorations and make a fresh one.

If you spot mould early you can take off the lid and put the Terrarium in the sun to attempt to kill the mould. You need strong, full sun and will need to spray and replace the lid at the end of the day.



PrasadC18 (author)2017-10-10

Can someone please advise if activate charcoal can be used in powdered form or is it absolutely imperative to use lumps. 2 - Can java moss be used? 3. will there any benefit from using fertilizers and Sphagnum moss? this is an inquiry for a self sustained largish terrarium

vitki (author)2017-09-28

I have a question about the active carbon. I found some on a Dutch webshop, but they have two types. They are both meant for brewing wine. They say one is for removing colour and the other is for removing taste and smell, however both are pure activated carbon. Do you know which of these two I should get? Or are they both the wrong type of activated carbon?

Thank you!

organgrinder (author)vitki2017-10-02

hiya, Go with the one to remove taste and smell. My partner says the difference is related to how they produce the "active" part of the carbon and the different sized "pores" that make carbon activated and how they remove the impurities in the alcohol :)

CourtneyH47 made it! (author)2017-04-21

After a year ...going strong

NordicaL (author)2017-04-14

I do love these little wonderlands! I found a rather large bottle at a jumble sale. it is quite heavy. planning a wee garden is what I would like to do. With some collected moss, would it also work to plant a succulent nib? perhaps a mini jade? thank you for sharing yoyr lovely ideas. if you have any other ideas, I coukd try, I would aporeciate it very much!

organgrinder (author)NordicaL2017-04-18

hiya You have to make sure that whatever mix of plants you use their conditions are compatible. From the succulents I'm familiar with they want a lot less water/moisture in the air than moss but you could alter how you make it such as not sealing it and spray the moss daily, this means the succulent wouldn't be too wet and I think succulents like open air (not sure on this, I'm not too familiar with them). Ferns work well with the moss in closed terrariums.
Good luck!

szohar (author)2017-01-05

How small can these get? I'm looking for some projects to do with old light bulbs, would that be an option for me?

Also, what kinds of plants are good for these?

organgrinder (author)szohar2017-01-07

I've done miniature ones in the bottles that essences or food colour comes in. I used the same method but you have to be very aware of how much you are putting in (remember 1/3 filled, 2/3 air). The best plants are those that like a humid environment and are happy without direct sun. Small ferns are great, begonia's and similar.

hannah0 (author)2016-09-28

I will soon be starting a school project in which we have to make a closed jar terrarium in a mason jar for a small snail to survive in for about two months, without ever opening the jar or making holes for air. We have a budget of $6. I'm pretty sensitive and I'm worried about the snail dying in our captivity, so I'm doing everything I can to make sure that my group conducts the experiment in the right way and that the snail survives. I would be thrilled if anybody could offer any advice or tips to make sure I do this right. Thank you!

AmberS113 (author)hannah02017-01-04

add some charcoal in the base layer to increase air quality then put soil and plants, choose some plants your snail can eat

organgrinder (author)hannah02016-10-02

Good luck! I bought home a tiny snail in my moss once and he lived for about 4 weeks.

Rubens?? (author)2016-10-13

can you make one instructable on how to make one of these for cactuses

BaileyS7 (author)2015-11-05

this might sound like a silly question but it's for a school project. is there anything thing that you can put in a terrarium and have it survive while never removing the lid or adding water for an entire year? we can't mess with it and can only observe it for the whole year.

AstroDude03 (author)BaileyS72016-09-22

If there are plants and water, maybe a small log or two, then ants should be able to survive and flourish. I have not tried other insects but I expect that they work as well.

KaitR1 (author)BaileyS72015-12-20

A month late, but I still wanna say that a David Latime planted a Spiderwort plant in a large jar, watered it once and sealed it. it's been thriving for forty years in a self-contained ecosystem; The water builds up in the bottle and rains back down, dead leaves rot and release carbon dioxide. Alternatives that come to mind would be an EcoSphere or BYOES; underwater self-substained ecosystems with shrimp, algae and some bacteria. I hope it's not too late for ideas! ^-^;;

Blue BrainG (author)BaileyS72015-11-25

Wether something drinks water or not if theres a tight seal they water probably wont get out put a bug in it or something

MarjorieD3 (author)2016-01-12

I want to put faux foliage in my glass cl;oche--can I use green moss as a cover,I have some in my yard (author)2015-03-30

Do you have finished terraniums for sale, or know sonewhere which sells them... After one for a gift.

GreggH1 (author)kahli.bingo2015-09-08

Check out Roosevelt's Terrariums in Portland, Oregon in the US. They ship kits and sell planted wet terrariums locally.

organgrinder (author)kahli.bingo2015-03-31

hi Kahli, No, I dont sell them but a quick google search found this place!/gallery

fluffypink (author)2015-07-28

You can buy activated charcoal at pet stores. It's used in aquariums.

gbet (author)2015-03-24

Organgrinder, you never made a comment either for or against preserved moss that won't get mould. Should I assume that you don't like it? Granted, I know real moss is much better looking but if there's a chance of it getting mould, and having to be replaced time and time again, isn't preserved moss at least an alternative to having a healthy enviroment inside a closed terrarium? I'm only asking this in order to learn. I'm not trying to tell people what they should do.

Thank you for your time and for your knowledge,


organgrinder (author)gbet2015-03-25

hi Gordon, I've never used preserved moss and stick to the real stuff. Living in Brisbane it is very humid here and our local moss likes that so tends to do well in closed Terrariums.
I always encourage my students to give things a go and see what happens. Have you used preserved moss successfully in closed Terrariums?

Around here you can also pick up hobby products that are made of plastic and are a great alternative to using real moss if you just like the look of the Terrarium but don't want the hassle.

gbet (author)2015-03-17

We all seem to want beautiful moss in either our open or closed terrariums. Regular moss seems to not like the very humid atmosphere in a closed terrarium and will develop mold which can spread easily.

The one moss that I've found that will not produce mold and will last for years is preserved moss which you can educate yourself about it using the search engine of your choice. This moss has been treated and needs misting when you first start to insert it inside your terrarium. Good luck!

yanjing.pak (author)2014-11-18

I am glad to see your instructions and experiences on Terrarium! I get started over the last weekend and hope my little planet will grow well. Thank you very much for your tips!

organgrinder (author)yanjing.pak2014-12-07

good luck!

AatroxD (author)2014-10-15

Hi, I am planning to do a terrarium, I will be using moss but I will but a snail in it, I have a question. What is the activated charcoal/carbon used for and if my plan is ok

organgrinder (author)AatroxD2014-10-22

the activated charcoal/carbon helps to clean the environment/acts as a filter as all of the air/moisture. The air/moisture kinda cycles through the carbon. Someone can probs explain that better but it is essential. Aquarium shops have it.

I once bought home a snail with some moss and had it living in my container of moss for about 8 weeks before it died (not sure why it died, maybe it didn't like being confined, lack of food, or snails don't live so long). I didn't let the snail go as I knew it was best left in the moss it came along on. I used to pop the top on the container of moss and let the snail get some fresh air. Other than that I can offer no snail advice. Is it a pet snail? Ask the pet shop people where you gotit?

kelly.a.smith.969 (author)2014-10-01

What kind of seeds do you recommend?

I have used grass seeds from the yard as well as bird seed and any other weed seeds. Give them all a go and see what takes :)

AatroxD (author)organgrinder2014-10-15

any type, as long as it can survive in the enviroment

lolanilly (author)2014-09-29


I noticed you used the finger like sphagnum moss. I have been trying to use that in my closed terrarium but have had to use reconstituted dry moss from a craft store since it's hard to find live moss here (I live in Arizona, it's super hot & dry), I've had a lot of issues with mold. It occurs within just a few days of creating the terrarium & I haven't had one successful trial with that moss. I've tried experimenting with just pebbles/no soil, sterilized soil, very little water, water with hydrogen peroxide (I saw an article on that elsewhere), cultivating a small batch first, a few other methods, with no success. I finally gave up & ordered live moss online but am curious if this is a common issue with that moss specifically? I even tried "washing" it, I get mold every single time. Is it possible that a closed terrarium in such a hot climate just isn't going to work? Any ideas/advice would be amazing!


organgrinder (author)lolanilly2014-09-30

How did things go with the moss you ordered??

I am thinking that this must be mould spores that are particularly insidious. As you are in a hot and dry climate you probably dont get a lot of mould taking hold but must have mould spores floating around all over that get in the terrarium (whether on the moss or even just in the air). when those spores get into the terrarium environment they thrive.

I'd recommend trying to use a LOT more of the activated charcoal. I used to have a lot of problems with the moss I collected out in the wild, it always got mould patches. Here in Brisbane mould is a problem as it is humid and we've also gone through a flood season recently that has set mould running crazy.

Do you know anyone with a greenhouse where moss is growing happily and mould free? I would recommend trying that.

Here in Brisbane the worst time for the moss is late winter, even in the greenhouse it is a bit gross and when I pick it I get mould issues. Usually just small patches I can isolate though.

I am not sure if your hot climate is an issue (how hot does it get?) as long as you keep them out of the sun and very hot spots. And usually in a dry climate people have trouble keeping their terrariums moist.

Good luck!

munderwood9 (author)2014-08-25

Hi OG (teehee). Quick question about your instruction to 'cultivate' the moss for a couple of weeks before putting it into a terrarium. Do you mean we should use another terrarium environment to check it out, or is something like a nice cream tub suitable?

organgrinder (author)munderwood92014-08-25

hi. The container needs to let light through, so a clear or frosted ice cream tub is suitable but not one where the moss will be sitting in the dark. Lid is essential.

jdempsey4 (author)2014-04-05

Hey I live on the Sunshine Coast and I was wondering if you get your carbon stuff local or shipped and where from? Thanks heaps

organgrinder (author)jdempsey42014-04-06

We got a bag of Activated Carbon from a Brew Shop in the Springwood area (south of Brisbane). Bunnings selling charcoal that is NOT activated. After some research this is usable but you have to use a lot. I'd say about a 1 cm layer.

alittle (author)organgrinder2014-08-21

You can actually buy activated carbon at most pet stores that sell aquarium supplies. It generally comes in much smaller bags/cartons, so you don't need to mail-order in bulk. A $6 US carton will easily be enough for a couple of terrariums.

Great instructable, thanks for sharing!

lamdee1 (author)2014-08-08

Do you know if a terrarrium will survive with artificial light alone? I have a tiny office in a school and it has no windows. I wondered if regular fluorescent or incandescent light would work. I could move it to an office with a window for weekends and holidays.

organgrinder (author)lamdee12014-08-10

Artificial light is not enough but it might be happy with just being a in a room with a window on the weekends. You should establish it first. To do that build it up and then keep it at home in a nicely lit space (no direct sun) for about 2 months, then transfer to your school office. After that ensure you give it natural light weekends. If it starts to look sad simply take it home for a week :)

annapippen (author)2014-02-01

Hey I was wondering what types of seeds you use?

organgrinder (author)annapippen2014-08-10

hi, I use grass seeds from grasses that grow around the place and bird seeds and anything else I find a seed of :)

organgrinder (author)annapippen2014-04-06

Sorry for not responding Anna, I don't recall getting a notification of your comment. I use bird seed, grass seeds and just about anything. You can always pull them out if they get too big :)

JakeSteel made it! (author)2014-05-04

I combined these helpful instructions with the directions found here:

ran into a few problems trying to get the moss inside the light bulb
without breaking the pieces up too much, but I am hoping that the moss
spreads itself around to fill the gaps.

Overall, I am happy with the results. Few places go into the level of detail that you did in this instructable. Thank you!

organgrinder (author)JakeSteel2014-06-01

Great! I have made Terrarium inside tiny jars and find that a pair of fine tweezers works well. Even if the moss is broken up when it starts to grow it should spread around & take hold. Also, you can clean your terrarium with some tissue on tweezers or a paddlepop stick with tissue wrapped around it.
How is it going?

Jack Corsair (author)2014-01-08

I have been at this for about 2 years now and I found your instructable so helpful. there were just a few little things I had been missing. Like how to deal with mold and why use activated charcoal. thank you thank you thank you!

Good luck, Jack! I hope you get some good Terrariums now. There is always more to learn, though. I recently realised the very back of one of mine is getting a little sun light on it and there is some orange sludge. Beware of direct sun!

Jack Corsair (author)2014-01-08

I have been at this for about 2 years now and I found your instructable so helpful. there were just a few little things I had been missing. Like how to deal with mold and why use activated charcoal. thank you thank you thank you!

je5ta (author)2013-06-08


I was wondering where abouts in Brisbane you found this moss or can you suggest some places? I live inner city so barely any can be seen around me =)


organgrinder (author)je5ta2013-06-09

I am in the northern suburbs out near the airport. I've also sourced some from out Logan way. If you are inner city you could pop out to the Botanic gardens, roma st parklands or new farm park for a wander about and maybe go on a wander round west end, sth bank area as a starting point, zig zag through as many streets as you can, especially after rain, like today :) After a while you get to be an expert at spotting it. I spot it everywhere now!

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