Pet Plant: Could You Love a ‘Marimo’ Moss Ball?
These fuzzy, velvety algae are considered a national treasure in Japan. Here’s how to grow and care for them
You may have seen these mossy-looking little cuties sitting tranquilly in small jars of water at hip plant shops or well-stocked aquarium stories. Marimo, or moss balls, aren’t actually mosses at all, but rather spherical algae native to shallow lake bottoms of Lake Akan in Japan as well as parts of Iceland, Scotland, Estonia and Australia. If you’re wondering why you’d place a jar of algae on your bookshelf, hear us out.
Marimo are plant pets — and guaranteed conversation starters — like no other. You can gently squish them, jostle them to encourage roundness, and even split and roll them into little baby balls to make more. If you can fill a jar with water, you can grow marimo. These aquatic organisms are happy to be left alone in a bowl of room-temperature fresh water in a spot with low to moderate indirect sunlight.
Marimo are plant pets — and guaranteed conversation starters — like no other. You can gently squish them, jostle them to encourage roundness, and even split and roll them into little baby balls to make more. If you can fill a jar with water, you can grow marimo. These aquatic organisms are happy to be left alone in a bowl of room-temperature fresh water in a spot with low to moderate indirect sunlight.
Where to put marimo. These algae need sunlight to photosynthesize, but they naturally grow in water depths of about 6½ feet — the lake water providing a buffer between the marimo and the ultraviolet light.
Mimic this exposure at home by placing a marimo in a jar of fresh water in a spot with low to moderate indirect light. Too much direct sun can cause it to turn brown, while too little light will cause it to turn gray. You may need to move your jar around until you find the light right exposure for the moss ball.
Mimic this exposure at home by placing a marimo in a jar of fresh water in a spot with low to moderate indirect light. Too much direct sun can cause it to turn brown, while too little light will cause it to turn gray. You may need to move your jar around until you find the light right exposure for the moss ball.
How to use marimo. Drop a marimo into a jar, vase or small fishbowl filled with fresh water and place it on a tabletop. You can grow multiple moss balls in medium-size containers or give each little guy its own jar. Marimo also thrive in fresh water aquariums, where they lightly bounce along the bottom if you have a bubbler submerged in the tank.
Purchase a fairly good-size marimo if you want a moss ball that will have some visual impact from the get-go, as these plants start out small and are slow-growing (about a fifth of an inch per year).
Browse decorative glass jars
Purchase a fairly good-size marimo if you want a moss ball that will have some visual impact from the get-go, as these plants start out small and are slow-growing (about a fifth of an inch per year).
Browse decorative glass jars
The owner of this marimo glued googly eyes to the glass, since the moss ball reminded her of Oscar the Grouch. Photo by maricielcarousel
Why we love them. Marimo are darn cute. With their fuzzy, velvetlike texture, emerald green color and darling round appearance, they’re like no other organism out there.
We’re not alone in our love of marimo. The native colonies of Aegagropila linnaei are protected in Lake Mývatn, Iceland, where their numbers have inexplicably been rapidly declining, and Lake Akan, Japan, where they are still abundant. In Japan, they’re considered a national treasure and are celebrated with a three-day marimo festival in Hokkaido, as well as with a children’s character, Marimokkori.
Why we love them. Marimo are darn cute. With their fuzzy, velvetlike texture, emerald green color and darling round appearance, they’re like no other organism out there.
We’re not alone in our love of marimo. The native colonies of Aegagropila linnaei are protected in Lake Mývatn, Iceland, where their numbers have inexplicably been rapidly declining, and Lake Akan, Japan, where they are still abundant. In Japan, they’re considered a national treasure and are celebrated with a three-day marimo festival in Hokkaido, as well as with a children’s character, Marimokkori.
Photo by maricielcarousel
Marimo care tips. Grow your marimo in an aquarium or clear glass container that will allow light to enter from all sides and make for better moss ball viewing. You can put your moss ball directly into bottled or purified water, or in tap water left to sit out for 24 hours to allow chlorine to evaporate.
Drop your moss ball in the water, and place the container in a spot with moderate indirect light. Keep the water vessel uncovered, or maintain a little air pocket at the top of a covered jar (and open the lid every so often) to allow for oxygenation. Change the water every couple of weeks, washing down the sides of the container to remove any unwanted, non-marimo algae growth.
The moss balls can also be grown in low-salinity saltwater aquariums (some sources say they can tolerate a salinity up to about 1.015), as they are sometimes found in brackish conditions in the wild.
If you’re growing marimo in a fresh or low-salinity aquarium with aquatic animals, check for debris buildup on the moss ball when you clean the tank. If you spot fish food or other detritus on the marimo, remove the ball from the tank and gently squeeze it out in a bowl of aquarium-safe water. Gently roll the marimo after you’ve squeezed it to keep the algae strands together and maintain the round shape.
Marimo care tips. Grow your marimo in an aquarium or clear glass container that will allow light to enter from all sides and make for better moss ball viewing. You can put your moss ball directly into bottled or purified water, or in tap water left to sit out for 24 hours to allow chlorine to evaporate.
Drop your moss ball in the water, and place the container in a spot with moderate indirect light. Keep the water vessel uncovered, or maintain a little air pocket at the top of a covered jar (and open the lid every so often) to allow for oxygenation. Change the water every couple of weeks, washing down the sides of the container to remove any unwanted, non-marimo algae growth.
The moss balls can also be grown in low-salinity saltwater aquariums (some sources say they can tolerate a salinity up to about 1.015), as they are sometimes found in brackish conditions in the wild.
If you’re growing marimo in a fresh or low-salinity aquarium with aquatic animals, check for debris buildup on the moss ball when you clean the tank. If you spot fish food or other detritus on the marimo, remove the ball from the tank and gently squeeze it out in a bowl of aquarium-safe water. Gently roll the marimo after you’ve squeezed it to keep the algae strands together and maintain the round shape.
Photo by agirlnamednee
In their native habitat, marimo act like underwater tumbleweed — staying round as they’re rolled by waves along the bottom of freshwater lakes. Grown in homes, moss balls benefit from being jiggled in their jar every so often to mimic this rolling motion and help encourage even, round growth. You may also want to flip the marimo over from time to time to ensure that all sides get adequate light (particularly if the bottom starts to look gray) and to prevent a flat side from forming.
In their native habitat, marimo act like underwater tumbleweed — staying round as they’re rolled by waves along the bottom of freshwater lakes. Grown in homes, moss balls benefit from being jiggled in their jar every so often to mimic this rolling motion and help encourage even, round growth. You may also want to flip the marimo over from time to time to ensure that all sides get adequate light (particularly if the bottom starts to look gray) and to prevent a flat side from forming.
How to propagate marimo. The moss balls are easy to split and propagate. Remove a larger moss ball from the water and gently separate it by pulling the spongy strands of algae apart with your fingers. Roll the algae in your palm into new baby moss balls — just as you would with a piece of felt. Submerge the baby marimo in clean fresh water, and they will very gradually grow into larger balls.
Where to find them. Marimo aren’t all that common yet, but they’re not too difficult to find if you know where to look. Your best bet is to visit an aquarium store that specializes in aquatic plants or freshwater fish, or find them online. Some trendy nurseries also sell them in little jars of water.
If you’re visiting an area in Japan, Iceland, Scotland, Estonia or Australia, where marimo are native, avoid buying them at lakeside souvenir shops to help protect the natural colonies.
Tell us: Have you seen marimo or grow them yourself? Share pictures in the Comments.
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If you’re visiting an area in Japan, Iceland, Scotland, Estonia or Australia, where marimo are native, avoid buying them at lakeside souvenir shops to help protect the natural colonies.
Tell us: Have you seen marimo or grow them yourself? Share pictures in the Comments.
More
Share the Love With an Adorable Heart Hoya Plant
10 Style-Boosting Design Ideas for Your Houseplant Collection
Common names: Marimo (Japanese for, roughly, water plant ball), moss ball, lake ball, cladophora ball
Temperature requirement: Room-temperature water
Water requirement: Should be fully submerged in water (bottled or purified, or tap water left to sit out for 24 hours)
Light requirement: Low to moderate indirect light
Mature size: Eight to 12 inches in diameter in lakes; closer to 2 to 3 inches across in jars and aquariums
Benefits and tolerances: Can provide water filtration in aquariums
Seasonal interest: Evergreen