Nephrolepis exaltata, commonly known as the Boston Fern or Sword Fern, is one of the most commonly recommended “terrarium plants”. It thrives in humidity and indirect light, which makes it sound ideal — but in practice, it is rarely suitable for enclosed terrariums due to its size and growth behaviour. Browse current listings here:
Boston Fern on Amazon.
Boston Fern summary
Key characteristics: Large fern, arching fronds, fast-growing Terrarium suitability: ★★☆☆☆ (2/5) Temperature: 18–24°C (64–75°F) Watering: Consistently moist, not soggy Humidity: Moderate to high (50–80%+) Growth rate: Fast Where to buy View on AmazonAmazon AU
Amazon US
Boston Ferns perform best in warm, humid environments with airflow. While terrariums provide humidity, they often lack the space and air movement this plant needs to remain healthy long term.
Terrarium suitability overview
- Closed terrariums: Not suitable
- Open terrariums: Limited use
- Small jars: Not suitable
- Large glass builds: Possible
Climate and environmental requirements
- Temperature: 18–24°C (64–75°F)
- Humidity: 50–80%+, prefers higher
- Light: Bright, indirect light
This combination of warmth, humidity and airflow explains why Boston Ferns perform well indoors — but not inside confined terrarium environments.
Why Boston Ferns are often recommended
- They tolerate humidity well
- They adapt to indirect light
- They are widely available and easy to grow
Why Boston Ferns struggle in terrariums
- Rapid growth exceeds container size
- Fronds press against glass
- Root systems quickly fill substrate
- Dense foliage reduces airflow
Where they actually work
- Large open terrariums
- Greenhouse-style displays
- As surrounding plants outside terrariums
- Very large custom glass builds
Water and substrate behaviour
- Requires consistently moist soil
- Does not tolerate drying out
- Needs well-draining substrate
Growth behaviour
- Fast-growing root system
- Long arching fronds
- Quickly dominates space
Compatible plants
Compared to compact plants like Fittonia, Boston Fern is far harder to control. Compared to mosses, it lacks scale compatibility. Compared to smaller terrarium ferns, it grows too aggressively.
Lifespan in a terrarium
- Short-term: Possible
- Long-term: Not suitable
Common issues
- Overcrowding
- Fronds pressing against glass
- Poor airflow
- Root congestion
Where to buy Boston Ferns
View on AmazonAmazon AU
Amazon US
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