Microsorum musifolium (Crocodile Fern)

Crocodile Fern, Alligator Fern, Crocodyllus Fern

Microsorum musifolium ‘Crocodyllus’

True to its name, the Crocodile Fern looks the real deal with its characteristic scaly green leaves and broad strap-like foliage. The clathrate scales (as they’re known in biology) are formed from deep emerald venation that deepens as the plant matures.

Native to Malaysia, in the wild these monsters are actually epiphytes (despite them growing up to 6 feet tall!) and are often found growing in the crooks of large trees. Thankfully, in a terrarium they’re likely to stay much smaller, but still larger than most terrarium plants. Just like the real crocs, these are a fantastic addition to larger tanks with lots of space and humidity and moisture.

At a Glance

Where to Buy the Crocodile Fern

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

Terrarium Plant Guide

Crocodile Fern Care & Growth

Lighting

Thanks to its native life in the canopy, the crocodile fern can actually handle a fair range of lighting conditions. They tend to stay a more vibrant green colour with moderate to bright, indirect light, but too much light will cause them to fade into a more silvery tone.

Watering

The crocodile fern is one of those tropical species that loves moisture, but doesn’t like its roots in soggy substrate. So, the challenge lies in maintaining consistent even moisture. That being said, this fern is not very drought tolerant at all, so it’s probably better to have it slightly too wet, rather than too dry. Keeping the humidity high and selecting an appropriate substrate mix can make this process a lot easier.

Substrate

Being an epiphyte in the wild, the roots of Microsorum musifolium are fairly shallow. A substrate with excellent water retention will help this fern maintain its moisture, but good drainage is important too as they’re not used to sitting in a wet substrate. Alternatively if you have the space, mount these bad boys up on the background.

Temperature & Humidity

When it comes to Microsorum musifolium, you’re going to want to keep the terrarium temperature and humidity as consistently high as possible. It doesn’t need super high temperatures, but it is sensitive to cold drafts.

Growth

The crocodile fern grows along a creeping rhizome, and reportedly these can grow huge in the wild (up to 6 feet!), but indoors – and especially in terrariums – they’re not likely to grow anywhere near that. Plus, they’re relatively easy to manage.

Propagation

As with most ferns, division is the easiest way to propagate the crocodile fern and this species does so readily. Gently tease apart the root system till you’ve identified the offset plants, then cut the rhizome with a sharp blade ensuring the new plant has plenty of roots of its own. Planting these directly back into the substrate should work just fine.

Varieties & Similar Plants

Coming from the same genus as the kangaroo fern, Microsorum seem to be the genus of animal related plants. With 50 other ferns in the genus (commonly known as wart ferns) there’s a huge amount of variation, but they seem to often share large and broad foliage.

Common Problems

Most of the challenges with this plant lie in keeping it consistently warm, humid and evenly moist. Which sounds tough, but in reality a typical closed terrarium environment is perfect for these plants, and you shouldn’t have too much issue with them.