Marimo moss ball care guide

Aegagropila linnaei

Also known as: Lake ball, Cladophora aegagropila

Pets and children

We haven't been able to confirm how this plant affects pets or small children. If any is eaten, consult a veterinarian or a doctor.

How often to water Marimo moss ball

Spring–Summer (Mar–Sep)
Every 7 days
Read watering as a water change: as a guide, replace all the water about once a week, and more often in summer when it warms up.
Autumn (Oct–Nov)
Every 10 days
With cooler water, a change about every ten days is enough.
Winter (Dec–Feb)
Every 14 days
Cold water stays fresh longer, so change it about every two weeks.

Light and placement for Marimo moss ball

As a guide, a bright room out of direct sun; it generally lives on ordinary room light, while direct sun at a window warms the water and turns it brown.

Overwintering Marimo moss ball

Overwintering guide: 0°C (32°F) or above

An alga from cold lakes, so winter cold is generally no problem as long as the water does not freeze; as a guide, keep it away from a heater's blast and from a window that heats up during the day.

Fertilizing and repotting Marimo moss ball

Fertilizer

As a guide, no fertilizer: tap water generally supplies what it needs, and feeding just clouds the water and grows algae.

When to repot

Repotting is not normally needed

Common problems with Marimo moss ball

  • Summer water above about 25°C turns it brown.
  • Direct sun at a window damages it.
  • Without water changes the water clouds and slime or other algae take over.

Tips for growing Marimo moss ball

  • Rolling it gently between your palms at each water change keeps it round.
  • If it floats, trapped gas is the cause; a gentle squeeze sinks it again.
  • On the hottest summer days, resting it in its container in the refrigerator's vegetable drawer for a few days is one option.

These are AI-generated general guidelines. They vary with the variety, the placement and the pot size. For effects on pets or children, consult a veterinarian or a doctor.

Keep your plant log going

Greenery is a free app that keeps your plant care going, with watering reminders and photo records. Available on iOS and Android.

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