Flowers & Blooms

Caring for Marimo Balls

Marimo Balls

Marimo balls are unique algae that work great as house plants. Due to their unusual shape and appearance, Marimo moss balls may seem artificial but they are completely natural. They are found only in selected lakes around the globe, in Japan, Estonia, Iceland and Japan. The shape of the algae is formed due to the slow movement of waves in the lake. Marimo balls are characteristic for their fuzzy texture and velvet feeling to the touch.

These beautiful plants are considered good luck charms in Japan. They are often kept as family heirlooms since they can live for 200 years or even longer. They are believed to represent close bonds between family members and friends. This is why they are often passed down to children, grandchildren and other relatives. Marimo balls continue to grow with each generation, which makes them more impressive. Alternatively, Marimo balls are considered a great gift for children who keep them as “pets”. Since Marimo moss balls require very little care they are ideal for children who wish to try gardening and plant care.

Young Marimo Balls are relatively small: between 2 and 2 ½ inches in diameter. Algae of this size are about 8 to 15 years old, while slightly bigger ones (3-4 inches) are around 20 years old. As a Marimo ball ages, it grows in diameter so old ones are 12 inches or even bigger in size.  As you can see by these numbers, Marimo balls grow very slowly, so it takes them a long time to reach size above 10 inches. If you have a relatively large Marimo ball and you would like a smaller one, simply cut the ball into smaller pieces. Each piece will grow into a separate Marimo ball you can keep in your home.

Marimo Ball Care

Marimo balls require very little care. You can grow them in tap water but it’s best to use filtered water because it makes moss balls remain clean for longer. Marimo balls can live in brackish water so you can add a bit ocean salt to the water if you notice that your Marimo ball develops brown spots.

These moss balls naturally live in cold temperature waters so you need to keep them in cooler water. Make sure that the temperature of the water for you Marimo balls is lower than 76 degrees F. If the water is too warm the balls may develop brown spots. This may happen during hotter months so make sure to give your Marimo ball a rest by putting it in a water-filled container and placing it in the refrigerator. Just make sure not to keep your Merimo balls in the refrigerator for longer than 24 hours.

You can keep your Merimo balls in aquariums but they can also thrive in vases, bottles or glass bowls. They don’t need air so you can even keep them in sealed containers. Just make sure that the container is big enough so your Merimo ball can fit inside without a problem.

Marimo Balls

Once you place your Marimo ball inside the container it may take a few days for it to sink to the bottom. Sometimes, there are air bubbles trapped inside the algae so it cannot sink. To get rid of the air bubbles, gently squeeze your Marimo ball while holding it under water. This should let the air bubbles out and the Marimo ball will sink.

You can keep your Marimo moss balls in containers with most animals, such as fish and shrimp. However, keep in mind that some animals may damage your Marimo balls. For example, goldfish, large-sized crayfish and some types of Plecostomus (Plecos) can damage your Marimo balls.

When to Change Water?

Another thing to keep in mind is water changing. This is vital for preventing dirt and waste building up in the container and hurting your Marimo balls. The exact dynamics of water changing will generally depend on the size of your container and the number of Marimo balls you own. If there is just one Marimo ball in the container, without any other plants or animals, you should change about half of the water ever two weeks.

However, if your Marimo balls are in the container with other plants and animals, make sure to change water more frequently. The exact dynamics will depend on the size of the tank and number of plants and animals. You may need to change water once per week or more frequently.

Lighting Requirements

Marimo balls naturally live at the bottom of a lake. In this sense, they don’t require much lighting. Typically, all they require is normal household light or indirect sunlight from windows. This should be enough to make your Marimo balls photosynthesize. They can also thrive under aquarium light and lamps.

When choosing the best lighting for your Marimo balls make sure you don’t go with something that’s too strong or intense. Don’t use direct sunlight or strong LED lights. Too much of light may cause brown spots on your Marimo balls.

It is a good practice to rotate your Marimo ball from time to time so it can receive enough light from all directions.

How to Clean Your Marimo Balls?

You will probably need to clean your Marimo balls from time to time. This is necessary if you don’t keep your Marimo balls with algae-eating animals, such as special fish or dwarf shrimp. If these animals are not present you will need to clean your Marimo moss balls periodically.

To clean your Marimo ball, simply take it out of the water and rinse it carefully. Place it in a container with clean water and gently squeeze it gently a few times. It is also a good thing to roll your Marimo moss ball in your hands while it’s submerged. This will simulate the movement of the waves. This will prevent your Marimo ball from becoming misshapen. You can do this rolling if you notice that your Marimo ball is already getting misshapen.

Photo credit: Nuwandalice Marimo via photopin (license)