Best plants for closed terrariums

A closed terrarium is a tiny, humid world in a jar. Pick the right plants and it mostly looks after itself. Pick the wrong ones and you'll be fighting rot or a plant that's pressed against the glass in a month. Here's what to look for, twelve beginner-friendly picks, and the popular plants to skip.

If you haven't built one yet, start with How to Build a Closed Terrarium That Stays Healthy. It covers drainage, soil and the lid.

What makes a plant suit a closed terrarium

Good closed-terrarium plants share three traits:

• They stay small, or grow slowly. A jar has no room to spare, so a plant that doubles in size every few weeks will crowd out everything else.
• They like humidity. Inside a sealed jar the air stays damp and water cycles from the soil to the glass and back. Plants from forest floors love that. Plants from deserts rot.
• They handle lower light. A terrarium belongs in bright, indirect light, never direct sun, which heats the glass and can cook the plants. Shade-tolerant plants do best.

Beginner picks by layer

Build in layers, the way a forest floor works: a ground cover, a few foreground plants, and one centerpiece.

Ground cover and moss

1. Cushion moss (Leucobryum). Soft, rounded mounds that stay low. Likes indirect light and damp, not soggy, conditions. Mist it if it starts to look pale or dry.

2. Sheet moss (Hypnum). A flat green carpet that's great for covering bare soil. It's low-light tolerant and very forgiving in a sealed jar.

3. Spikemoss (Selaginella kraussiana). Not a true moss, but it looks like a feathery, bright-green one. It loves high humidity and gentle light. Trim it if it spreads too far.

4. Baby tears (Soleirolia soleirolii). A carpet of tiny round leaves. It thrives in humidity but grows quickly, so plan to snip it back now and then.

Foreground

5. Fittonia, or nerve plant (mini varieties). The classic terrarium plant, with leaves veined in white, pink or red. Choose a mini type. It likes humidity and indirect light, and it droops dramatically when dry, then perks back up after watering.

6. String of turtles (Peperomia prostrata). A tiny trailing plant with round, patterned leaves. It grows slowly, likes indirect light, and doesn't want the soil waterlogged.

7. Creeping fig, mini variety (Ficus pumila). Small leaves that climb and trail over rocks and wood. It likes humidity and moderate light. It will spread, so trim it to keep it in bounds.

8. Pilea glauca ('Aquamarine'). Tiny silvery-blue leaves on trailing red stems. It suits the front of a jar and likes bright, indirect light.

Centerpiece

9. Lemon button fern (Nephrolepis cordifolia 'Duffii'). A compact fern with small, rounded leaflets. It loves humidity and handles medium light. It's one of the easier ferns for a jar.

10. Emerald ripple peperomia (Peperomia caperata). Deeply crinkled leaves in a neat clump. It grows slowly, likes indirect light, and shouldn't sit in soggy soil.

11. Earth star (Cryptanthus). A small, star-shaped plant with striped or colorful leaves that stays low and flat. It's a bold focal point for a wide jar.

12. Table fern (Pteris cretica). Feathery, often variegated fronds. It likes humidity and indirect light. Choose a small plant, and trim older fronds as it grows.

Plants to avoid

• Succulents and cacti. They're built for dry air and fast-draining soil. In a sealed, humid jar they tend to rot. Put them in an open container instead.
• Fast growers, like pothos, tradescantia (wandering dude) and polka dot plant. They're easy houseplants, but they quickly outgrow a jar and shade out their neighbors.
• Air plants (Tillandsia). They need airflow and to dry out between waterings, which a closed jar doesn't give them.
• Venus flytraps and other plants that need direct sun or a winter rest. A sealed jar can't give them strong light or a cold dormancy.

Matching plants to your jar size

• Small jars, like a mason jar or a small cloche: one ground cover plus one or two small plants, such as moss with a mini fittonia or string of turtles.
• Medium jars: a moss or spikemoss carpet, two or three foreground plants, and a small centerpiece like a peperomia.
• Large jars and tanks: room for every layer, including a fern or earth star as the focal point.

Leave space between plants. Everything grows, and a little breathing room now saves you from crowding later.

Ready to sketch your layout? The free course lesson Plan Your Build walks you through choosing a container and placing plants before you plant anything.

FAQ

Do closed terrariums need sunlight?

They need light, but not direct sun. Bright, indirect light, like a spot near a window that's out of the sun's direct path, keeps plants healthy without overheating the glass.

How often should I water a closed terrarium?

Rarely. A balanced jar recycles its own water. Add a little only when you stop seeing condensation and the soil looks dry. Too much water is a more common problem than too little.

Can I put succulents in a closed terrarium?

Not a good idea. The constant humidity usually makes them rot. Grow them in an open container instead.

What do I do if a plant gets too big?

Trim it with small scissors, or swap it for a smaller plant. Regular light trimming is a normal part of terrarium care.

Why is there mold in my terrarium?

A little is common in a new build and often comes from too much moisture or decaying plant bits. Remove dead leaves, take the lid off for a few hours to let it air out, and cut back on water.