DIY Japanese Marimo Moss Ball Terrarium

A DIY glass terrarium blog post has been LONG overdue given the incredibly large selection of glass terrarium and other terrarium containers Vase Market keeps in stock. It's embarrassing really. But FINALLY, we did it. Here's our take on how to decorate a very simple glass terrarium. If you're not into dirt or you're not big on gardening, no worries. This is one of the easier types of terraiums to start with, and I'd say it's probably the best choice for any beginner looking to grow something green without having to worry too much about taking care of it. Japanese marimo moss balls are one of the easiest things to maintain and, dare I say, the cutest little things nature has ever come up with, second to puppies and kittens.

Things You'll Need

A glass terrarium bubble bowl with an asymmetrical / slant cut opening

Vase fillers help level out the base of your glass terrarium, while bringing an element of gorgeous color

A Glass Terrarium
Stone or Glass Vase Fillers
Japanese Marimo Moss Balls
Black Sea Tree / Sea Fans / Fan Coral
Aquarium-safe figurines and other decor

There are a variety of options and combinations you can make using Vase Market's glass terrarium and vase fillers. In this particular example of what I did, I used a glass terrarium slant cut bubble bowl. You can get these as a 6 inch diameter glass terrarium or as an 8 inch diameter glass terrarium. I used the six inch because I don't have a lot of space in my home for anything too big. A single pound bag of sea glass was perfect for my six inch glass terrarium, and it created a lovely layer of color along the bottom of the bowl. The opening of the glass terrarium I used is slanted and rather small, so if you have bigger hands, it might be hard to use. If this is the case, I would recommend our bubble bowl glass terrariums, which have bigger openings and are also popular as fishtank aquariums.

All other items must be bought separately from places that specialize in aquatic plants and aquatic pets. Marimo balls are a common accessory for betta fish tanks, so if will be easy to find marimo balls at your local pet store. If you keep betta fish, you can consider keeping them with a marimo ball. Betta fish will play with them by rolling and pushing them around the tank, which is healthy for the marimo ball as well. The marimo ball itself acts as a filter that picks up nitrates and cleans the water. You'll also find pently of aquarium decor at a pet store to place in you glass terrarium. Sea fans or dried fan coral are very common and popular decorative accents to couple with marimo balls, but you'll have a better chance of finding those online.

Things To Know About Marimo Moss Balls and Glass Terrariums

Petshops often sell real live marimo moss balls as accessories for betta fish tanks

1. The Life of a Marimo - The first thing to know is that marimo balls are actually not moss at all. They are a type of algae (aegagropila linnaei) that accumulate and grow, typically in cool waters of lakes where sunlight rarely reaches them. The wild ones are commonly found in Iceland and Japan. If you are able to care for it well, they can grow indefinitely in your glass terrarium. However, you'll have to be patient. They only grow a few milimeters each year.

2. Water - Because marimo moss balls are supposed to stay submerged underwater, it is arguable that what we're making is more accurately an aquarium rather than a terrarium, but few are debating about the issue so there's no need to concern yourself with semantics. What is imortant is keeping your terrarium cool, preferably under 70 degrees F. You can use regular filtered water or tap water, but if you are concerned about the chlorine content in your tap water (which can make your marimo sick), you can fill the glass terrarium up with tap water and let it sit for 24 hours. This will allow the chlorine to evaporate, and then it will be safe to place your marimo balls in the water. You could also use an aquarium filter or dechlorinator.

3. Health and Care - Remember that marimo balls in nature don't often see sunlight, so keep your glass terrarium in a place that's cool and won't heat up from direct sunlight. The balls may turn brown if exposed to too much light. However, because they are algae, they do need some light for photosynthesis. Regular room lighting should be fine, but be sure to sometimes roll your marimo moss balls around inside the glass terrarium. This ensures that every part of the ball gets a bit of light for healthy growth. I keep a swizzle stick around (see image below) for this purpose. You should also clean your glass terrarium and change the water every 2-3 weeks.

2 green marimo moss balls, frosted blue sea glass vase filler, and white river rock pebbles

2 green marimo moss balls, frosted blue sea glass vase filler, and white river rock pebbles

Use a swizzle or stirring stick to occasionally turn the marimo balls inside the glass terrarium

Safe Decor for your Marimo Moss Ball and Glass Terrarium

When it comes to the type of vase filler, any kind of rocks, glass, or substrate that's considered safe for plants, fishtanks, and aquariums are a safe bet for your marimo moss ball glass terrarium. I used white river rocks, frosted light blue sea glass, and a few opalites to give the glass terrarium some vibrancy and contrast, as well as light refraction. As long as it's safe, just go with what's right for you!

Dried fan coral branches are safe decorative accents for your marimo balls and glass terrarium. They look like regular twigs and aren't the most impressive to look at outside the water, but I personally love the way the fan coral is magnified by both the water and the glass terrarium, creating a fantastic backdrop to the scene. Unlike the branches of normal trees, fan coral is extremely sturdy and hard to bend or break. As long as you're sure of who you're buying from, these dried fan coral branches should be perfect and will not shed or decay. They also should not affect the salinity of your water.

Dried sea fan coral for marimo terrariums

Dried sea fan coral for marimo terrariums

Typically, among decorative objects, any kind of material that isn't safe to eat from is probably not safe for your terrarium. Rule of thumb: If you're not sure that it's safe, don't include it at all. Even with natural materials such as wood, rocks, and sea shells found in nature have the potential to bring unwanted toxins, chemicals, hostile algae, or pesticides. Glass, plastic, and polyresin are usually safe.

Sometimes the concern is not the material itself, but the paints or embellishments that color the object. Enamel and nail polish coats are usually pretty safe, but if you've used these paints on your own handmade figurines, make sure they are properly cured before putting them in the glass terrarium. Certain types of acrylic paints are safe too. Do your reseach before hand. Otherwise, just stick to the approved aquarium decor found in pet stores and fish shops.

Plastic figurines for glass terrarium decor

Plastic figurines for glass terrarium decor

I was lucky enough to get my hands on some plastic Studio Ghibli themed figurines made specifically for glass terrarium decor. However, due to contrained space, I chose to only place one figurine in the glass terrarium bowl.

The Finished Marimo Ball Glass Terrarium

Together, these elements make the cutest little marimo terrarium!

I personally love the way the fan coral is magnified by both the water and the glass terrarium

To learn more about caring for marimo balls, check out these resources:

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