Terrarium Care

Your terrarium is a living ecosystem — not a decoration that needs perfection, but a tiny world that wants balance. These are the things I’ve learned across years of building, losing, recovering, and celebrating miniature worlds in the tropical humidity of Far North Queensland. Most of the time, they’re remarkably forgiving. Trust them a little, and they’ll find their way.

Light & Placement

Bright, indirect light is the sweet spot for nearly every terrarium. Think the light you’d find near a window — bright and generous, but not direct sun blazing through glass. Direct sun through a closed or semi-closed terrarium acts like a greenhouse and will cook your plants faster than any mistake you could make with watering.

• Place near a bright window, but out of direct sunlight

• Avoid heaters, air-conditioning vents, and drafts — the temperature swings are stressful

• Rotate occasionally if you notice plants leaning toward the light

• Fluorescent or grow lights work well if natural light is limited

FNQ note: In tropical Queensland, morning sun is gentler than afternoon sun. An east-facing spot is often ideal — bright mornings, shaded afternoons.

Watering

This is where most people go wrong — and almost always in the same direction. Over-watering. A terrarium is not a pot plant. The closed or semi-closed environment holds moisture, recycles it, and needs far less water than you’d expect.

Open terrariums

• Water lightly when the top layer of soil feels dry to the touch

• Mist gently rather than drenching — you’re maintaining moisture, not soaking

• Distilled water or rainwater is preferred; tap water can leave mineral deposits on glass

Semi-closed terrariums

• These need water far less frequently — sometimes only every few weeks

• Watch the glass: light condensation is healthy and normal

• Heavy dripping condensation means too much moisture — open the lid for a few hours

• Dry glass with soft or slightly drooping plants is a gentle sign to add a small amount of water

When in doubt — wait. The number one terrarium mistake is adding water when the ecosystem just needs time.

Condensation & Airflow

A little fog inside your terrarium is a sign it’s working — the ecosystem is breathing. It’s one of the most satisfying things to witness, especially first thing in the morning.

• Light moisture on the glass is completely normal and healthy

• Heavy fogging or dripping: remove the lid for 1–2 hours to release excess moisture

• Wipe the glass gently with a clean cloth if needed — but don’t obsess over it

• If your terrarium has a lid, use it as a dial: more lid = more humidity, less lid = more airflow

Microfauna — The Tiny Workforce

If you see tiny white specks moving through your soil or on the glass — congratulations. Those are springtails, and they are exactly what you want. Many of my terrariums also include isopods. These aren’t pests. They are the cleaning crew, the composters, the ecosystem managers. They break down organic matter, prevent mould, and keep everything in balance.

Please don’t reach for a spray. They are doing their job.

Managing your springtail population

If numbers seem low in the first few weeks, you can offer tiny amounts of supplementary food to help the colony establish:

• A grain-sized piece of mushroom

• A thin slice of cucumber

• A pinch of brewer’s yeast

• 1–2 grains of uncooked rice

Remove any uneaten food after a few days if it begins to look or smell unpleasant. Once the colony is established, they’ll find everything they need naturally.

“But my plants are dying and there are bugs everywhere —”

Stop. The springtails did not do this.

Springtail populations boom when there is excess moisture or decaying organic matter in the terrarium — which means if you’re seeing an explosion of tiny white creatures, your ecosystem is flagging something else entirely. Usually too much water. The springtails didn’t cause the problem; they showed up to fix it.

What to do if numbers spike:

• Stop supplementary feeding immediately

• Check moisture levels — over-watering is almost always the culprit

• Remove the lid for a few hours to increase airflow

• Remove any decaying plant matter you can see

Please wait — the population will regulate itself naturally once the food source reduces

Springtails cannot harm your plants. They do not eat living plant tissue. They eat fungi, mould, and decomposing matter — which makes them one of the most valuable things living in your terrarium. Give them a little time and they will do their job.

Want to know more? Head to the Isopods & Springtails page — it goes much deeper into the fascinating world of terrarium microfauna.

General Maintenance

Terrariums are low-maintenance by design — but they do appreciate occasional attention.

• Trim plants as needed to prevent overcrowding and maintain the scene you love

• Remove yellowing or dead leaves promptly — they can harbour mould if left

• Clean the glass gently with a damp cloth when needed

• Give new terrariums a settling-in period of a few weeks — small changes usually correct themselves

• Earthy, soil-like smell is normal and good. Sour or rotting smell means something needs attention.

What to look out for!

Worth watching

• Yellowing leaves — too much water or not enough light

• Drooping or crisp plants — needs moisture

• Persistent heavy fogging — excess moisture, needs airflow

• Plants leaning strongly to one side — rotate toward light

Take action

• Dripping condensation that doesn’t clear

• Soil smelling sour or rotten

• Plants collapsing despite correct care

• Visible mould spreading (small spots are normal; spreading is not)

A Note for FNQ terrarium owners

Cairns and surrounds bring their own gorgeous complexity to terrarium keeping. The wet season changes everything — ambient humidity rises dramatically, and your terrarium’s needs shift with it.

• Check moisture levels more frequently during the wet season — the terrarium may need almost no added water at all

• Airflow becomes more important — don’t leave lids fully sealed for extended periods

• In the dry season, semi-closed terrariums may need watering slightly more often than usual

• Plants sourced locally are already adapted to these conditions — they’re often more resilient than you’d expect

🌿A PERSONAL NOTE: Every terrarium that leaves my hands is a minimum of three months old — established, settled, and already showing new growth. They're not new to the world, just new to yours. The first few weeks are simply about watching and letting it find its rhythm in your home environment and light. If something doesn't look right, or you just want reassurance please reach out. There’s no silly question when it comes to a living thing you’re caring for. I’m always here. 🌿