The crocodile fern, Microsorum musifolium, is a tropical plant with crocodile-skin-like leaves. This exotic stunner comes from the rainforests of tropical Australia but it can bring a taste of this environment to far-flung regions when it is grown as a houseplant indoors.
What is Crocodile Fern?
Crocodile ferns thrive in a humid tropical environment. But by replicating the right conditions inside our homes, those of us living in temperate climates far from the native range of these plants can grow them well.
These are slow-growing epiphytic ferns that take their name from the appearance and texture of their leathery, glossy green leaves, distinctly patterned with darker veins, which resemble the skin of a crocodile.
Where to Grow Crocodile Fern
Crocodile Ferns are grown indoors where temperatures outdoors drop below around 10 degrees C., and certainly, anywhere that experiences frost and sub-freezing temperatures. These ferns are suitable for indoor growing.
But you do need to make sure that they get the right conditions. Be sure to look at all the important environmental factors, including light, temperature, and humidity, and the growing medium in which your fern will grow.
It is essential to avoid placing a crocodile fern in harsh, direct light that could damage the plant. Especially during the warmest and brightest part of the year, these ferns need filtered light/ partial shade. It is important to choose a spot out of direct light, so avoid, for instance, placing them in a window.
Remember, these plants are native to the rainforest, below the canopy of rainforest trees. So we need to mimic the dappled light reaching through that canopy to these plants below.
Temperature & Humidity Requirements
Since these are tropical ferns, they do require quite high temperatures year-round. They will do best indoors in zones lower than 10 or 11, where they would be killed off outdoors by winter cold.
Ensure that temperatures remain above 10 degrees Celsius as an absolute minimum, and ideally keep temperatures steady between around 16 and 24 degrees. Try to avoid placing these ferns where temperatures can suddenly change, in cold draughts, or too close to a heat source in your home.
Humidity is another very important factor when growing crocodile ferns indoors. These ferns need humid conditions. So place them in a humid location such as a terrarium or bathroom.
Where humidity is lower, you can raise it by grouping houseplants together, misting, and/or placing pots on top of shallow saucers filled with water and pebbles.
Soil/ Growing Medium
Crocodile ferns are typically grown indoors in pots containing equal parts loam, orchid bark, leaf mold, or other peat substitute, and charcoal, to provide them with the free-draining growing medium that they need. A mix that is neutral to slightly acidic in pH will be ideal.
Planting Crocodile Fern
Crocodile ferns can be propagated using the spores. However, most domestic growers will simply purchase a pot online or in a plant nursery or garden center and then repot it into a new pot to grow it on at home.
These ferns require a pot just a bit larger than the current root system, filled with a suitable growing medium. Make sure that you do not bury your fern too deep and that, with their shallow roots, they sit at the same level that they did in their previous pot.
Caring for Crocodile Fern
Crocodile ferns, if placed in the right location, do not need a great deal of care. The main things that you need to do are water and feed your plant, and remain vigilant for any pests or other problems. As these ferns grow only very slowly, you will likely not need to repot very often.
Consistent and deep watering is important with crocodile ferns. Not watering the right way leads to many of the most common problems encountered when growing these ferns.
The amount and frequency of watering will depend on several environmental factors including temperatures, humidity, and light levels but as a general rule, you should water whenever the top few centimeters of the growing medium is dry.
Watering can likely be significantly reduced in winter and plants will typically need most water during the peak summer season, even when growing indoors.
Water thoroughly and deeply, to ensure moist conditions. But make sure excess water can drain away freely from the base of the container.
Ferns only need light feeding, if they need feeding at all. This is true of crocodile ferns. But when growing these ferns indoors, it is a good idea to use a dilute, balanced, organic liquid plant feed on your plants, around once a month through spring and summer.
Crocodile ferns are fairly hassle-free and as long as you bear all of the above in mind, they are not temperamental plants.
The most common problems relate to how a plant is positioned and cared for. They arise from issues like too much direct light, lack of water, and over-watering or waterlogged conditions, which can lead to root rot if they persist for too long.
Like many ferns and other houseplants, they may also have an issue with pests like scale insects or other sap-suckers, or other common indoor pests like mealybugs or spider mites, to give a couple of examples.
Though crocodile ferns are slow growing, if allowed to do so they can reach 3-5ft in size. Crocodile ferns can remain in a pot for quite some time, but will eventually often become particularly root bound, or top-heavy.
At this point, they can either be divided or repotted into a larger container – just a little larger than the container that it is currently in. Make sure when you are repotting that the plant remains at the same depth within the soil.