Girl Scout Activities: Marimo Terrarium

Marimo Terrarium

As a Girl Scout troop leader, I am always busy looking for new ideas for our troop and to keep my girls entertained.  This is something you can do with a variety of ages, and it is part activity and also educational.  You can adjust the activity many different ways depending on your troop.

This is not the cheapest “craft” type of idea, but we already had some materials and you can make this into an entire meeting.  What is a Marimo?  A small algae ball that is easy to keep in a small terrarium.

Supplies needed:

Marimo moss balls
Glass jars
Rocks, glass beads, shells, “sea glass”, aquarium gravel, etc.
Ribbon or twine

The first thing I did was order the Marimos from Amazon.  There are different sizes, but the most economical way to go was to order a multi-pack of the small ones from  Our Marimos were tiny, and cost $8.95 for a pack of 6 (Amazon Prime).  A single large Marimo can cost $10, so the small ones were much more cost effective.  If you order from Amazon, read the product descriptions carefully so you know exactly what size and quantity you are getting (some were even mixed sizes).

Marimo Moss Balls Amazon

As you can see, the Marimos are definitely are small, but the girls thought they were cute!

I purchased the jars at Walmart.  They were not my idea choice, but I wanted something with a lid and it had to be inexpensive.  The jars ran about $0.60 each, and I told the girls they could always switch out the jar with a different one if they wanted when they got home.  There are some gorgeous jars with corks, but those are generally at least a couple dollars each.

The key was to also find jars without a lot of markings designs, like measurements, logos, or other designs that would distort the view of the contents.

Marimo Moss Ball

The first thing I had the girls do was start filling a jar with whatever they wanted.  I didn’t have an unlimited supply of colors when it came to the glass rocks, so I asked them to be aware of using up all of one color and making sure they were sharing with their fellow Girl Scouts.  (Being that it was Chinese New Year, we had just finished trying to eat rice with chopsticks!)

Marimo Moss Ball Girl Scouts

I also had regular rocks to choose from – all of which I purchased at Dollar Tree – but you can find at craft stores and online.

Marimo Moss Ball Rocks

marimo Moss Ball Jars

Next, we added a Marimo ball.

Then the girls filled their jars with water.  Ideally, you want water that has sat out for about 24 hours, so that it naturally dechlorinates.  You could prepare the water at home in a jug ahead of time.

Lastly, the girls secured their lids, and if they chose to, they tied on a ribbon.  Some of the girls also wrote on the lids, but I would have liked to be more prepared with different colors of Sharpies (as regular markers will wipe off).

Marimo Moss Ball Ribbons

As part of the experience, I wanted the kids to learn about their Marimo Moss Balls. I talked about how these are actually algae balls that grow in lakes, and how the idea of keeping Marimo balls at home originated in Japan.  I had each girl create a little care sheet so that they knew how to spell Marimo, and they wrote down that they should change the water every couple weeks and to keep the moss ball in low/medium light.  (Ideally, the water should be dechlorinated, which I explained to parents).

You can easily add other learning lessons to this activity, discussing things like photosynthesis, how plants breathe, lake ecosystems, aquarium ecosystems, and more.

This is one of our huge Marimo moss balls we have at home.  The kids love making little terrariums for friends and family as gifts.  As a troop leader, you can save the extras if your family wants to make extras with the leftover supplies.

Marimo Terrarium

I had fun seeing how the girls decorated their little terrariums, and they seemed intrigued at the idea of the Marimos.  While we haven’t made this part of a patch or badge unit yet, we may end up incorporating it into a spring “plants” themed patch.

Cost breakdown:
Marimo moss ball: $1.49 each
Jars: $0.61 each
Rocks and gems were $1 per bag and I used ribbons I had around the house.  Check places like Dollar Tree and Christmas Tree Shops!

By | 2018-03-02T16:18:22+00:00 February 27th, 2018|Crafts|18 Comments

About the Author:

Busy blogger and mom of two girls! We love traveling and the great outdoors, and are always looking for our next adventure!


  1. Rosie February 27, 2018 at 6:54 pm - Reply

    This is a super cute idea. And the kids must love you for scouts, you have so many good ideas. I never heard of a Marimo moss ball before! Knowing these are something to care for, can be very nurturing for kids. Luv!

  2. Dana Rodriguez February 27, 2018 at 9:23 pm - Reply

    What a fun idea for kids and I am sure they had a lot of fun making these. I have never heard of Marimo Moss Balls.That is really awesome!

  3. Leelo March 4, 2018 at 3:22 pm - Reply

    This is such a great activity for kids! I have never heard of Marimo moss balls before. I have to check those out.

  4. AJ March 4, 2018 at 4:32 pm - Reply

    How fun! I’m sure my girls would love this activity! I’m sure being a Girl Scout troop leader keeps you pretty busy, but how fun!

  5. valmg @ Mom Knows It All March 5, 2018 at 11:21 am - Reply

    What a fun project! I remember being in Girl Scouts when I was younger and we did some fun things. I like that this one can be educational as well.

  6. Vanessa Palma March 5, 2018 at 10:27 pm - Reply

    What a great craft! I didn’t even know what Marimos were until I read this. Now I’m off to do this with my kiddos.

  7. Diana Ajih March 5, 2018 at 10:54 pm - Reply

    Looks like such a fun and creative project! I also like that it’s educational. My two nieces are in girl scouts and they would love this.

  8. Barbies Beauty Bits March 6, 2018 at 2:04 am - Reply

    Look how cool and pretty I love the colors. So happy to see projects that do not involve being in front of a computer.

  9. Jennifer Van Huss March 7, 2018 at 10:45 pm - Reply

    I’m a sparks leader so I’m always looking for cool ways to introduce the world around them to the girls! This is such a cute craft! I love that it is something that will also teach them about respect and responsibility!

  10. Heathe March 8, 2018 at 4:25 am - Reply

    This looks like a fun project! I wonder if my daughters troop will do something similar.

  11. Victoria Heckstall March 8, 2018 at 11:07 am - Reply

    Such a cute and fun idea. I have to try this with my kids. They will surely love this.

  12. Nancy at Whispered Inspirations March 8, 2018 at 12:52 pm - Reply

    Wow this is really neat. It looks like a fantastic idea! I would love to do this with the kiddos soon. What a fun an interesting project for over March Break.

  13. Melissa Dixon March 8, 2018 at 3:37 pm - Reply

    Wow this is a really fun idea. I have never tried anything like this but my daughter would enjoy it, for sure!

  14. Kathy March 8, 2018 at 7:04 pm - Reply

    This is a really neat idea. I think they turned out great. This is exactly something that my girls would love. They doing doing craft stuff like this.

  15. Lynndee March 8, 2018 at 8:00 pm - Reply

    I have always loved terrariums. I think they are really cute. I have never thought of creating one myself though. What a fun idea to do with the kids.

  16. This is a cool project for kids to do. It would be perfect for science class too. I want to make some of these jars without the moss/water. I love the look of the small fish tank rocks and the bigger rocks. Then add in a succulent too.

  17. Cyn Gagen March 8, 2018 at 11:22 pm - Reply

    What a fun idea! I have never heard of Marimos before but they look really cool.

  18. Dhemz March 9, 2018 at 5:17 pm - Reply

    That is pretty cool and super fun! My daughter would love this kind of activity. Thanks for sharing!

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