Tips to Care for Fern Plants Both Indoor and Outside
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Did you know there are roughly 12,000 species of Fern plants in the class Polypodiopsida? Each one is a non-flowering house or garden plant that works perfectly for hanging baskets, as a potted plant, or as ground cover outside. And there are Ferns native to almost every region and climate, including the US. While they all require similar care, being able to identify which type of Fern you have is important because some can thrive in the cold while others are tropical.
Tropical Ferns like the Maidenhair Fern and even the Boston Fern prefer higher humidity and may not be able to stand up to cold winters, while Ferns from temperate or desert regions like the Wavy Scaly Cloakfern are more drought-tolerant and beginner-friendly.
Plant fact: While most Ferns are pet safe, the Bracken Fern is considered toxic and should be kept out of reach of small children and animals.
These herbaceous plants can thrive both outdoors and indoors with the right care. This guide to Fern care shares tips and tricks to care for your Fern, including watering schedules, lighting needs, and common health issues.
Fun Fact: The term “pteridomania” or fern fever was coined in the 19th-century Victorian era as it was in fashion to grow as many different types of ferns in your home as possible, not unlike us today.
Table of Contents
Where Ferns Originate
Ferns have been around with lineages dating back hundreds of millions of years and span over 12,000 species all across the world, except Antarctica. Many are found as ground cover in warm areas with dappled light and high humidity, like rainforests and swamps so caring for them would be like caring for a traditional tropical houseplant like Pothos.
Some grow as epiphytes like the Bird’s Nest Fern like Monstera plants vs. being rooted in the ground, so they need to get nutrients and water from the host they climb. A few like the Holly Fern live like Lithophytes in rock crevices and need a similar type of environment like the epiphytes as they aren’t always rooted in the earth. And a few species of Fern are native to Africa, the American Southwest, and Asia, like the Holly Fern, and have adapted to the drier climate by becoming drought-resistant. While all Ferns love water, not all can handle the same levels of it, or even climates. That’s where identifying your type of Fern comes into play.
Fun fact: Ferns are considered living fossils and nicknamed “dino salad”, as their ancestors were a food source for herbivorous dinosaurs.
Classification and Details About Ferns
Ferns and their fronds are not one-size-fits-all and vary across the 12,000 species. Some have wider leaves in heart shapes like the Heart Fern vs. the signature blades of the Boston Ferns we picture in our heads. There’s even ones like the Birds Nest Fern that extend like octopus legs and ruffled fronds like the Curly Boston that resemble kale more than a standard Fern.
The foliage of the Fern can be a sign of where it comes from and how it grows, and that can help you make the slight adjustments needed to keep your Fern thriving.
Rainforest Ferns tend to have wide, flat, and simple leaves as the shape helps them catch all available sunlight under the canopy.
Dry area species foliage is more likely to have tiny, deeply cut, or lacy leaves to cut down water loss in the wind and heat.
Cold weather Ferns grow thicker, leathery, and stiffer leaves to help protect the plant from frost damage.
Epiphytic species are more likely to grow two types of leaves on one plant where one leaf hugs the tree trunk to catch falling dirt and water and the other leaf grows outwards to make spores.
With 12,000+ known species, it's important to make sure your plant is an actual Fern and not a similar looking plant like a Jacob’s Ladder to ensure you give it the proper care and habitat.
Fun fact: There are around 380 species of Fern native to North America.
Names |
Fern, Polypodiopsida, Polypodiales, Common Fern, Vascular Plant |
Subclasses |
Equisetidae, Ophioglossidae, Marattiidae, and Polypodiidae |
Common Species |
Nephrolepis exaltata (Boston Fern), Asplenium nidus (Birds Nest Fern), Davallia fejeensis (Rabbits Foot Fern), Athyrium niponicum (Japanese Painted Fern) |
Leaf colors |
Green |
Spathe colors |
n/a |
Variegation |
Yes |
Fenestration |
No |
Root type |
Rhizome |
Height grown indoors |
1-3 feet |
Height grown outdoors |
1-25 feet (varies by species) |
Width |
1-6 feet (varies by species) |
Time to maturity |
2-5 years (varies by species) |
Soil PH |
4-7 for most. 7-8 for Maidenhairs, Ebony Spleenwort, and Hart’s Tongue |
Soil type |
Aerated, Well-Draining |
Blooming |
N/A |
Flower type and color |
N/A |
Pet safe |
Varies by Species |
Total species |
Over 10,000 |
Propagation techniques |
Division, Spores |
Fern Care Instructions
While there are thousands of fern species, how to care for them remains mostly consistent. For Fern with larger leaves that compete for sunlight in the rainforest, you may need a slight bit less sunlight, while drought-tolerant Fern won’t need as strict of a watering regiment.
Watering
Ferns need watered every 5 to 7 days when the top 1-2 inches of potting mix feel dry. Add water until the excess drains from the pot's drainage holes to thoroughly moisten the potting mix. When watering, avoid wetting the fronds as this can lead to fungal growth.
Sunlight
Most Ferns prefer bright indirect light for at least 2-6 hours a day. Place by a window with light filtered by a gauze curtain or shade cloth, or in a spot that receives ambient light (no direct sunbeams). If on the windowsill, choose an East or North facing window that avoids the hot afternoon sun which can cause leaf burn.
Ferns grown in your garden outside do well in full or partial shade as long as they are planted away from the afternoon sun.
Pro-Tip: For your outdoor garden, look for evergreen ferns with root systems that tolerate dried summer soils and can survive winter like the North American native Christmas Fern (Polystichum Acrostichoides) or perennials like the Ostrich Fern (Matteuccia Struthiopteris).
Humidity and Temperature
Most Ferns prefer a humidity range of 40-80% which matches most homes. Ferns from tropical regions, like the Boston Fern, will thrive in the higher end of the spectrum but tolerate standard home humidity levels. Desert ferns like Fairy Swords (Myriopteris Lindheimeri) and Wavy Cloak Fern (Astrolepis Sinuata) come from more arid regions and prefer closer to 50%.
If your home is a little too dry, humidifiers with a built-in humidistat can help monitor and maintain indoor levels or try increasing humidity with:
Plant groupings
A pebble tray with water under the pot (make sure the water level is lower than the tops of the pebbles)
Placing it in naturally humid rooms like the kitchen or bathroom
For very dry home climates, you may want to increase watering frequency and check your potting mix every few days vs. every 5 to 7.
Ferns require a temperature range similar to typical home temperatures from 60-75°F (15-23°C). Your plant can tolerate brief cold spells below 50°F (10 °C), but prolonged exposure can cause cold damage or plant death. Also make sure to keep them away from vents, air conditioners, and heaters.
Pruning
Ferns do not need pruned more frequently than other plants, but when they turn brown the brown foliage may stand out more against the lush greens and variegation on rare varieties. Use sterilized shears to remove the brown fronds at the soil line and discard it in the trash. This encourages new growth.
Health Issues to Look For
Ferns do not flower, so their fronds are the best indicator of non-ideal conditions. Here are some common ones and what to do.
Fun fact: Some The Ostrich Fern and Royal Fern are deciduous and drop all their fronds every year. This is a sign of a healthy plant.
Discoloration
If the fronds are shriveling, wilting, or turning brown, check if the soil is too dry as you may be underwatering. Add water to the soil until it feels damp but not wet, and water begins draining from the bottom of the pot. Make sure your potting mix is well-draining but does retain some moisture.
Pro-tip: You can add more sphagnum moss or chunky to help increase moisture retention.
Fronds that are turning brown and wilting with crispy edges can also be a sign of low humidity. Increase ambient humidity by adding a humidifier with a built-in humidistat nearby or place a pebble tray with water under the pot. Moving your fern to naturally humid rooms like the kitchen or bathroom, or placing it in a plant grouping can also increase humidity
If the fronds are turning yellow, appear pale, or have started dropping, this is a sign of overwatering, so reduce the watering frequency and check for bacterial or fungal growth. Check the top few inches of your potting mix to make sure it isn’t waterlogged.
For overall pale fronds, the issue is too much direct light reducing chlorophyll production and causing the color to fade. by reducing chlorophyll production as a protective mechanism. Ensure your Fern is not in direct sunlight, and move it to a less sunny area when this happens.
Pale or greyish leaves might also be due to underwatering, so you’ll want to increase watering frequency, especially in the hotter summer months. Pale green leaves might also be lacking nutrients, so you can try adding liquid fertilizer diluted to half strength once every 2-3 weeks to boost struggling plants.
Sun and Leaf Burn
Loss of color or brown spots along the edges that progressively worsen, and drooping fronds are signs of leaf burn.
If you notice these signs, try:
Moving the pot to another position with only indirect light exposure or into the shade.
Pruning any fronds that appear mostly brown/badly damaged to help the plant focus on new growth.
Ensuring the potting mix for indoor Ferns and soil for outdoor Ferns remains adequately watered.
Root Rot
Ferns have roots that are susceptible to root rot if left in soggy soil where water fills the air pockets in the pot, promoting fungal and bacterial growth. Black spots on the roots, leaves, or stem, and a foul smell will be your first indications of root rot.
If you suspect root rot, remove your plant from the pot and:
Trim any rotting or dead roots with sharp, sanitized shears. If it is discolored, smells or feels squishy, trim it away.
Treat the roots and the container the Fern is planted in with a hydrogen peroxide solution (3 parts water to 1 part peroxide) or plant-safe fungicide to make sure all bacteria and other potential threats are washed away.
Re-pot in new well-draining potting mix, ensuring the pot has holes in the bottom for proper drainage.
Pro-tip: After watering, remember to wipe off excess moisture from the leaves as this can also promote fungal and bacterial growth.
Potting Mix and Nutrition
Most ferns prefer a well-draining potting mix with lots of organic matter and chunky media like perlite, charcoal, moss, and bark, to prevent soggy soil and allow the roots to aerate. Our signature blend of potting mix Dirt Bag is designed specifically for plants that are susceptible to root rot and provides ample nutrients for growth.
Our Dirt Bag potting mix is pH-balanced and can be adjusted to suit every fern, whether they prefer acidic or basic potting mix. Our Sphag bag, which is 100% sphagnum moss, can also be blended in as a neutral mix-in so plant parents can control nutrition levels.
Ferns enjoy fertilizer during the growing season, which for most is in the Spring and Summer. Make sure to dilute liquid fertilizers to half-strength and apply every 4-6 weeks during Spring and Summer and avoid fertilizing in the winter if your fern is known to go into dormancy during that period.
Fun fact: Foxtail Fern and Asparagus Fern are not Ferns as they reproduce by seeds, not spores.
