Fern Soil & Care Guide
Ferns are flowerless plants with intricate foliage and a frond leaf (divided leaf) structure.
Most fern stems (also called rhizomes) grow horizontally, making them perfect indoor plants.
But some varieties, like tree ferns, have elevated rhizomes and grow vertically.
Popular indoor fern varieties include:
Boston fern (aka Sword fern or Nephrolepis exaltata)
Maidenhair fern (Adiantum)
Japanese holly fern (Cyrtomium falcatum)
Staghorn fern (Platycerium) — a popular variety of epiphytic ferns
Button fern (Pellaea rotundifolia)
Bird’s Nest fern (Asplenium nidus)
Fancy an evergreen fern for your garden?
Suitable outdoor fern varieties include:
Autumn fern (Dryopteris erythrosora)
Asparagus fern (Asparagus setaceus)
Cinnamon fern (Osmunda cinnamomea)
Ostrich fern (Matteuccia struthiopteris)
Lady fern (Athyrium filix-femina)
You can even grow some outdoor fern varieties (like ostrich fern) inside, but they need specific conditions to flourish as houseplants.
Here’s what you need to know to grow fern plants:
1. Choose the Right Soil for Ferns
Ferns have a shallow root system and require potting soil mix that’s:
Loose to support their fibrous root ball.
Moist and well-draining (ferns thrive in damp and humid conditions).
Rich in organic matter to provide the nutrients for fern growth.
Looking for the best soil mix for growing ferns?
Instead of regular potting soil, use a soil mix specifically crafted for ferns, like Rosy’s fern mix.
This well-draining soil mix is perfect for all types of ferns — perennial ferns, evergreen ferns, tropical ferns, or even a deciduous fern.
2. Maintain Adequate Moisture Levels
Most ferns need moist soil to thrive.
How do you ensure optimum humidity when growing ferns indoors?
Here are a few pointers to help you grow fern plants:
- Water your potted fern when the top 2-3 inches of soil is dry to keep the soil moist. Overwatering could cause root rot.
- Place a humidifier near a potted fern. It’ll help prevent the browning of leaves (common in the southern maidenhair fern).
For dry regions, consider a fern plant that prefers low humidity, such as:
- Bird's Nest fern
- Boston fern
- Holly fern
- Staghorn fern
- Rabbit’s Foot fern
3. Provide Indirect Light Exposure
Most indoor and outdoor fern varieties require plenty of indirect sunlight year-round, especially during fall and winter.
Plant ferns in areas with dappled shade (or partial shade).
Some hardy fern varieties, like northern maidenhair fern, can survive under full sun.
But direct sunlight can dry the soil and damage fern frond leaves.
4. Other Fern Care Tips
Some best practices for a healthy fern plant include:
Pick indoor and outdoor ferns according to your region. In the US, go for native fern varieties like lady fern or Christmas fern (Polystichum acrostichoides).
- Prune dead frond leaves periodically to promote new growth.
- Some ferns, like maidenhair ferns, need alkaline soil. If you have acidic soils, add limestone to increase the pH.
- Periodically add mulch to your indoor fern potting soil to increase moisture retention and organic matter.