The crocodile fern (Microsorum musifolium), also known as the crocodyllus fern or alligator fern, is an exotic and statement-making houseplant. With its strikingly textured foliage resembling crocodile skin, it’s easy to see how this plant got its common name.
Native to tropical forests in Southeast Asia and Northern Australia, the crocodile fern thrives in warm, humid environments with bright, filtered light. With the right care, these ferns can grow up to 5 feet tall and make an unforgettable addition to any indoor plant collection.
In this ultimate guide, we will cover everything you need to know about successfully growing crocodile ferns.
👀 Overview
The crocodile fern is characterized by its broad, light green fronds that emerge in a rosette shape from the base of the plant. The leaves are segmented and have a wrinkled, leathery texture marked by dark green veins that resemble the skin of a crocodile.
These tropical ferns typically grow up to 5 feet tall and wide in the right conditions. The plant grows via a shallow network of woody rhizomes and fine, hair-like roots located just below the soil’s surface.
Native Habitat
In their natural habitat, crocodile ferns grow as epiphytes attached to trees and rocks in the dense, humid rainforests of Southeast Asia and Northern Australia. Specifically, they are native to areas including:
- Southern Myanmar
- Indonesia
- Borneo
- Philippines
- Malaysia
- New Guinea
- Thailand
- Tropical northeast Australia
The plant thrives in the warm, stable temperatures and high humidity of the rainforest understory. It is well-adapted to getting bright, dappled sunlight filtered through the upper canopy.
| 📖 Common name | Crocodile Fern, Crocodile Fern, Alligator Fern |
| 🔬 Botanical name | Microsorum musifolium |
| 🫴 Care Difficulty level | Moderate |
| ☠️ Toxicity | Non-toxic to pets and humans |
| 💨 Air-purifying Qualities | Low |
| 🌱 Soil Type and pH | Well-draining, rich, organic soil; slightly acidic to neutral pH |
| ☀️ Sun Exposure | Bright, indirect light |
| 🍪 Edibility | Non-edible |
| 🌴 Plant type | Fern |
| 🍃 Foliage Type | Evergreen |
| 🌿 Color of leaves | Dark Green |
| 🌸 Flower color | N/A |
| 💥 Bloom time | N/A |
| 🚀 Growth Speed | Slow to Moderate |
| 📏 Mature Size | 18-24 inches tall |
| 🔄 Life Cycle | Perennial |
| 🌍 Hardiness zones | 10-11 |
| 🗺️ Native area | Southeast Asia |
💚 Crocodile Fern Care
Caring for a crocodile fern involves providing the right amounts of light, water, humidity, and nutrients. With attention to these key factors, these tropical plants can thrive for years as indoor houseplants.
☀️ Light ☀️
In their native habitat, crocodile ferns grow under dense rainforest canopies where they receive ample bright, filtered light. Recreating these conditions is important for their health and appearance.
The plants prefer bright, indirect sunlight. Direct sun will scorch and bleach out the foliage. A few hours of early morning sunlight is acceptable, but afternoon sun should be avoided.
Ideal places to situate your crocodile fern are:
- Near an east or north-facing window
- In a bright bathroom or kitchen
- Under a canopy of taller houseplants
- In a terrarium or greenhouse cabinet
Rotate the plant periodically to prevent it from leaning towards the light source. Watch for signs of too much light, like pale and yellowed leaves, and relocate to a shadier spot if needed. Insufficient light will cause slow, stunted growth.
💧 Water
Crocodile ferns require consistently moist soil to thrive. The exceptions are during winter when growth slows, and for mature plants in larger containers that retain more moisture.
Check the soil moisture by touching the top few inches of soil. Water thoroughly whenever it feels slightly dry. The plant should be watered 2-3 times per week in general, allowing the excess to drain out.
Always water in the morning to prevent fungus issues. And avoid getting water on the crown where the leaves emerge, as it can lead to rot. Use room temperature water rather than cold tap water to avoid shock.
The most common watering issues are overwatering and underwatering:
- Overwatering causes root rot and leaves to yellow and drop. Allow the soil to partially dry out between waterings.
- Underwatering leads to dry, crispy leaf edges and stunted growth. Increase watering frequency and volume.
Providing the right soil mix (see next section) and drainage holes will help prevent overwatering issues.
🪴 Soil
A rich, moist, and well-aerated potting mix works best for crocodile ferns. The soil should retain moisture but also drain well to avoid standing water.
Here are two suitable potting mix recipes:
- 1 part peat moss, 1 part perlite or coarse sand, and 1 part compost – The peat and compost provide moisture retention and nutrients, while the perlite/sand component improves drainage.
- Tropical plant potting soil amended with 20-30% perlite or orchid bark – Look for bagged mixes made for aroids and other tropicals, then add perlite or orchid bark to improve aeration and drainage.
When potting, lightly pack down the soil around the roots to stabilize the plant. But avoid compressing it too firmly as crocodile ferns have shallow, fine root systems.
🍼 Fertilizer
Crocodile ferns are light feeders but do require occasional fertilizer to look their best. Use a balanced, diluted liquid fertilizer during the active growing season of spring through summer.
Most indoor plant fertilizers can be used at 1/4 to 1/2 strength. Choose options labeled for ferns and tropicals. Apply once every 2-4 weeks.
Reduce or stop fertilizing in fall and winter when growth naturally slows. Flush the soil monthly with clean water to avoid buildup of salts that can burn the delicate roots.
If you notice fertilizer burn (brown leaf tips), cut back on the fertilizer strength and frequency.
🌡️ Temperature
The crocodile fern thrives in warm conditions similar to its native tropical habitat. Ideal temperatures are between 70-80°F (21-27°C) during the day and 60-70°F (16-21°C) at night.
Avoid exposing the fern to temperatures below 55°F (13°C) or rapid temperature drops, which can damage the foliage. Cold drafts from windows or doors can also harm the plant. During winter when indoor temperatures drop, take measures to keep the fern’s environment warm.
Move the crocodile fern to the warmest room in your home before temperatures fall below 60°F (16°C). Keep it away from drafty windows, doors, or air vents. You can also provide extra warmth by placing the pot on a heat mat or warming tray set to 70°F (21°C).
Small space heaters are another option for giving the fern supplemental heat during cold months. Just take care to keep the fern out of direct contact with the heat source which may dry it out.
In summer, the crocodile fern appreciates moving to a shaded outdoor location when daytime temperatures are between 70-85°F (21-29°C). Outdoor spaces offer increased humidity and gentle air circulation the fern enjoys. Just be sure to bring the plant back indoors before night temperatures drop too low.
Consistent warm temperatures are critical for the crocodile fern. Monitor conditions daily and take steps to maintain an ideal temperature range year-round. Proper temperatures ensure your fern stays lush and actively growing.
💦 Humidity
Humidity is essential for crocodile ferns to mimic their native rainforest climate. They require a minimum of 60% humidity, but do best at 70% and above.
There are several options to increase humidity around your crocodile fern:
- Use a humidifier
- Place on a pebble tray filled with water
- Group plants together to create a microclimate
- Mist leaves frequently with room temperature water
- Grow in a terrarium or greenhouse cabinet
Signs that humidity is too low include dried out, crispy leaf tips and margins. Increase your humidity-boosting efforts if this occurs.
📃 Types of Crocodile Fern
There are a few different recognized varieties of the crocodile fern (Microsorum musifolium):
- Microsorum musifolium var. musifolium – This is the most common variety. It has bright green, glossy fronds with the characteristic crocodile tail-shaped lobes. The lobes are slightly rounded at the tips.
- Microsorum musifolium var. nagurum – This variety has pointed, more elongated lobe tips that lack the rounded shape. The foliage may be a bit thinner in texture.
- Microsorum musifolium var. macrophyllum – The fronds on this variety grow much larger, up to 16 inches long. It also displays darker green foliage.
- Microsorum musifolium ‘Metallicum’ – This cultivar has unique fronds that emerge with a striking metallic coppery sheen before darkening to green. The new growth remains reddish.
- Microsorum musifolium ‘Crocodile’ – A patented cultivar with typical crocodile-shaped lobes. It is compact and slower growing.
- Microsorum musifolium ‘Green’ – Another patented variety noted for its bright apple green colored fronds that lack red hues.
There are also some related Microsorum species:
- Microsorum punctatum – Often called the microsorum fern, it has solid undivided fronds unlike the deeply lobed M. musifolium.
- Microsorum steerei – Native to Malaysia and Thailand. Its fronds split into long thin finger-like lobes.
So in summary, the crocodile fern has a few named varieties that differ in foliage color, texture, and growth habit. But Microsorum musifolium var. musifolium is by far the most commonly found type in cultivation.
🪴 Potting and Repotting Crocodile Fern
Crocodile ferns prefer being a bit rootbound and only require repotting every 2-3 years. Repot in spring before the main growing season.
Choose a container that is 2 inches wider than the current pot. Make sure it has drainage holes. Gently tease apart any circled roots before placing into fresh potting mix. The rhizome should sit just below the soil surface.
After repotting, keep the soil moist but not saturated while the plant re-establishes. Delay fertilizing for a month until new growth emerges.
✂️ Pruning Crocodile Fern
Occasional pruning maintains an attractive form and promotes new growth:
- Remove dead or damaged fronds by cutting at the base with sterilized scissors. This improves appearance and airflow.
- Trim crowded clumps for a fuller, bushier plant. Take care not to prune too aggressively or you may damage the rhizomes.
- Keep foliage dust-free by gently wiping with a damp cloth to improve light absorption. Avoid leaf shine products and harsh chemicals.
Other than pruning, crocodile ferns require minimal grooming when kept in their favored conditions. Wipe leaves if they become dirty, trim off unattractive growth, and remove spent foliage.
🌱 How to Propagate Crocodile Fern
The easiest propagation method is by division in spring. Carefully tease apart the roots and rhizomes and pot up the divisions in a peaty potting mix. Keep humidity high while the divisions establish.
Another option is by rhizome cuttings. Take 3-4 inch pieces that have a growth point and roots attached. Plant in soil and enclose in a plastic bag for added humidity as they root.
Propagation via spores is more difficult. Spores are tiny and require sterile conditions to germinate successfully into new plants. This method is not suitable for inexperienced gardeners.
Here’s an easy process for crocodile fern propagation:
- Identify a mature, healthy frond displaying visible tiny plantlets along its edge. The plantlets will look like mini leaves emerging from the fern.
- Use sterilized scissors or pruners to carefully cut off the portion of frond containing plantlets. Remove as little of the frond as possible.
- Transfer the cutting to a small pot filled with moist sterile potting mix. Bury the lower portion of the cutting slightly below the surface.
- Enclose the pot in a clear plastic bag to create a greenhouse environment. Do not seal the bag completely.
- Place the cutting in bright, indirect light. Avoid direct hot sun which may cook the tender plantlets.
- Keep the soil moist but not saturated. Remove the plastic bag after 4-6 weeks once new growth is evident.
- Transplant the new plantlet into a regular potting mix. Treat it like a mature crocodile fern by providing bright light and consistent moisture.
With this method, you’ll have a fully rooted and established baby crocodile fern to enjoy in about 3-4 months. Take several cuttings at once to increase your chances of success.
🐛 Common Pests
Crocodile ferns rarely suffer pest infestations when provided good care. But issues can develop if the plant is stressed from improper conditions.
Potential pests to watch for include:
- Scale insects – Look for small bumps on leaves and stems. Wipe off with alcohol or treat with horticultural oil or insecticidal soap.
- Mealybugs – Cottony white masses on leaves and roots. Apply neem oil or insecticidal soap.
- Root mealybugs – Cause stunted growth. Knock off soil and treat with systemic insecticide.
- Fungus gnats – Harmless but annoying. Let soil dry out between waterings and use sticky traps.
Prevention is key – provide good airflow, optimal humidity, and plenty of light. Isolate new plants before introducing to your collection.
🩺 Common Problems With Crocodile Fern
When given proper care, the crocodile fern is not prone to many issues. But there are a few potential problems to watch for:
- Leaf scorch – Direct hot sunlight burns the foliage, causing brown dry spots. Filter the light to prevent damage.
- Leaf yellowing – This indicates too little water and humidity. Increase both immediately to restore the foliage’s healthy green color.
- Leaf drop – Significant leaf drop results when the plant is excessively dry or exposed to cold drafts. Improve growing conditions to stop frond loss.
- Slow growth – Inadequate light, moisture stress, or cold temps cause stunted growth. Assess its care and make adjustments as needed.
- Root rot – Overwatering or poor drainage may cause root rot. Repot the plant in fresh mix if fungal disease sets in.
- Insect pests – Mealybugs, spider mites, and scale insects may appear. Isolate and treat with horticultural oil or insecticidal soap sprays.
- Leaf spots – Bacterial or fungal disease shows as dark marks on fronds. Improve air circulation and remove affected parts immediately.
Prevention is the best way to avoid issues. Observe your crocodile fern regularly for early signs of distress, and take quick action to resolve any problems.
🖼️ Display Ideas
- Show off texture – Place where fronds can be backlit and admired up close
- Elevate above eye level – Use plant stands and hanging baskets
- Group with other tropicals – Combine with prayer plants, orchids, and bromeliads
- Let it trail – Repot in a hanging container and allow fronds to cascade
👍 Pro Tips for Healthy Growth
Follow these tips to keep your crocodile fern looking lush and beautiful for years to come:
- Acclimate new plants slowly to your home’s conditions. Avoid abrupt changes in lighting, humidity, etc.
- Group plants to boost local humidity. This creates an ideal microclimate crocodile ferns enjoy.
- Flush the leaves with tepid water monthly to remove any accumulated fertilizer salts or minerals.
- Prune away any damaged or diseased fronds using sterilized pruners. Make cuts near the base of the stem.
- Turn the plant occasionally to encourage even, upright growth. Staking may help keeps heavy fronds upright.
- Repot in fresh soil annually even if the roots haven’t filled the pot. This prevents nutrient depletion over time.
- Monitor soil moisture frequently and never let the plant sit in soggy soil. Crocodile ferns are prone to root rot if overwatered.
- Consider moving the plant outdoors in warm weather to give it a growth boost. Provide ample shade and bring it back indoors before nights get cool.
- Propagate new plants often. Divide when repotting or take frond cuttings. This allows you to expand your fern collection!
❓ FAQ
📝 Final Thoughts
With their uniquely textured, crocodile skin-like foliage, these tropical ferns make an eye-catching addition indoors. They are lower maintenance than many houseplants if provided consistent moisture, bright filtered light, warm temps, and high humidity.
Following the care and cultivation tips provided in this guide will help you be successful in growing crocodile ferns. Be sure to assess your individual plant’s needs and make any adjustments to your care routines to address issues if they arise. With the right conditions, your crocodile fern will produce lush fronds and grow for many years to come.
📚 Further Reading
📚 Visit the Crocodile Fern Hub Page for more info about this plant
📗 Boston Fern
📗 Staghorn Fern
📗 Bird’s Nest Fern
📗 Maidenhair Fern
📚 References
📘 Flora Details for ID 3747 – National Parks Board Singapore.
📘 Species Details for 27728 – Malaysia Biodiversity Information System.
📘 PMC Article 6347172 – National Center for Biotechnology Information.
📘 Taxon Information for 2650529 – Mindat.org.
📘 Category: Microsorum musifolium – Wikimedia Commons.
