Terrariums are famously low-maintenance, but "low" isn't "no". Get these five things right and yours will thrive for years with only occasional attention.
1. Bright, indirect light, never direct sun
Most terrarium plants want bright but indirect light. Direct sun turns a closed jar into an oven and scorches leaves. A spot near (not on) a window, or a grow light in a dim room, is ideal.
2. Water sparingly, let the terrarium tell you
A sealed terrarium recycles its own moisture, so it may need water only every few weeks or months. Water only when condensation stops forming on the glass; a light misting is usually plenty. More terrariums die from over- than under-watering.
3. Manage condensation
A little fog is healthy. Heavy, permanent condensation means it's too wet, take the lid off for a day to let it breathe, then reseal.
4. Prune and tidy
Snip back plants that outgrow the glass, and remove any yellowing leaves promptly so they don't rot. A pair of long tweezers makes this easy.
5. Match plants to the terrarium type
Closed terrariums suit humidity-lovers (moss, ferns, fittonia); open ones suit succulents and cacti. Mixing the two is the most common beginner mistake, see open vs closed.
Frequently asked questions
How often should I water a terrarium? Closed: only when condensation stops (often weeks/months apart). Open: when the substrate dries out.
Why is my terrarium going mouldy? Usually too much moisture or a dead leaf, air it out and remove decaying matter; a springtail cleanup crew helps.
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