The Complete Guide to Fern Moss (Thuidium delicatulum)

Thuidium delicatulum is a wonderfully textured type of Fern Moss, and as you’d expect looks just like a miniature fern. But, sometimes not so miniature. It can grow quite large for a moss.

It’s found in many countries, but tends to thrive in damp grasslands, woodlands and in shaded rocky areas. It’s a pleurocarpous moss, meaning it’ll form a dense layer when added to a terrarium.

Thuidium Delicatulum (Fern Moss)

Where to Buy Fern Moss

See the links below to purchase from reputable terrarium plant shops and marketplaces (may include affiliate links). 

US – See on Etsy
UK – See on Etsy

Thuidium delicatulum Care & Growth

Plant TypeMoss
LightingMedium – high indirect light
Temperature60-80°F (15-26°C)
WateringRegular, even moisture
HumidityHigh humidity (60-90%)
Growth1-3 inches


Thuidium delicatulum will do well in shaded environments. It can tolerate some partial sun but keep it out of direct sunlight to avoid leaf burn.


Fern moss likes a lot of moisture in its environment. It’ll do best in a closed terrarium environment, or will need regular misting in an open terrarium.


As this Fern Moss loves damp wetland conditions, you’ll need an appropriate tropical substrate that can retain plenty of water but still drain properly.

Temperature & Humidity

Thuidium delicatulum is known to thrive in damp environments so it will grow in high humidity just fine. It’s naturally found in a variety of environments, so it should tolerate a variety of terrarium conditions.


Fern Moss tends to grow relatively slowly, but will form a thick carpet eventually. It’s generally pretty easy to look after, so give it time and it will form a healthy moss layer in your terrarium.


Much like other carpeting terrarium mosses, Fern Moss will happily propagate through division. Tearing off patches and placing them around a terrarium will help it grow much faster than a single colony would.

Varieties & Similar Plants

Fern Moss is a term used for variety of moss species from the Thuidium genus. These include Kilt Fern Moss (Thuidium recognitum) and Tamarisk Moss (Thuidium tamariscinum).

Common Problems

Though Thuidium delicatulum likes a high degree of moisture, take care not to let it sit in stagnant water. It won’t survive even partially submerged and will rot if constantly waterlogged.