What Are Marimo Moss Balls? Origin, Care & Everything In Between
The Short Answer
Marimo are genuinely one of the lowest-maintenance living things you can keep. Fresh water every one to two weeks, a spot with soft indirect light, and an occasional gentle roll. That's it. No feeding, no fertiliser, no special equipment.
If you've just welcomed a Moonling home and want the full detail behind each of those three things, here's everything you need.
How to Care for Your Marimo Moss Ball
1. Change the Water
Change the water every one to two weeks using cool, fresh tap water. Gently pour out the old water, give the jar a light rinse if needed, and refill.
Marimo prefer cooler temperatures, so if your home runs warm in summer, a few hours in the fridge during a water change does them good.
2. Find the Right Light
Marimo thrive in indirect light, a windowsill that gets bright but not direct sun, or a spot near a window that's partially shaded. Direct sunlight will cause them to brown and deteriorate over time.
Think of the kind of light that feels comfortable to sit in, not the kind that makes you squint.
3. Roll It Gently
Every few weeks, gently swirl or roll your marimo in your hands when you change the water. This mimics the natural lake current that keeps them round and ensures every side gets light. It takes about ten seconds and makes a real difference over time.
What to Expect After Delivery
It's completely normal for a marimo to look slightly different after its journey to you. Small colour or shape changes after transit are expected, and your Moonling will settle back into itself within the first week or two once it's had a proper water change and some time in its new spot.
If anything still seems off after that settling period, we're always happy to help. Just reply to any of our emails or reach out directly.
Signs Your Marimo Is Happy
A healthy marimo is a deep, rich green. You may notice tiny oxygen bubbles gathering on its surface after a water change, this is a completely normal part of photosynthesis, and a good sign that it's thriving in its light. Some marimo even float gently to the surface as bubbles collect, then sink back down as they release. It's one of those small, easy-to-miss moments that makes marimo owners feel oddly fond of their little companions.
Frequently Asked Questions
How often should I change my marimo's water?
Every one to two weeks, using cool, fresh tap water. Change it more often in warmer weather.
Can direct sunlight kill my marimo?
Direct sunlight won't kill it outright, but prolonged exposure will cause it to brown and deteriorate. Indirect light is best.
Why did my marimo change colour or shape after arriving?
This is a normal response to transit. Give it a fresh water change and a settling period of a week or two in its new spot, and it should return to its usual self.
Do I need to feed my marimo?
No. Marimo photosynthesise and absorb what they need from the water. No feeding, fertiliser, or special equipment required.
Why does my marimo have bubbles on it?
Tiny oxygen bubbles are a normal and healthy sign of photosynthesis. It's a good indication your marimo is happy in its current light.
Want to Know More About Your Marimo?
If you're curious about the meaning behind your Moonling, the Ainu legend, and everything else marimo carry with them, we've written the full story here: Read: What Does Marimo Mean? The Complete Guide →
