Complete Guide To Fishtail Sword‑fern Care and Growth

Quick Overview

The Fishtail Sword Fern (Nephrolepis falcata) is a captivating member of the sword fern family, admired for its unique foliage. Each frond is forked at the end, creating a distinctive shape that looks just like a fish’s tail. Native to the lush environments of Southeast Asia and Australia, this fern brings a touch of the tropical rainforest indoors.

It’s an excellent choice for both beginners and experienced plant parents due to its relatively easy care requirements and non-toxic nature. With its graceful, arching fronds, the Fishtail Fern is perfect for adding texture and vibrant green color to hanging baskets, pots, or terrariums.

How much light does a Fishtail Sword Fern need?

Fishtail Sword Ferns thrive in bright, indirect light. Think of the dappled sunlight they would receive on a forest floor. An ideal spot is near an east-facing window where it can get gentle morning sun, or a few feet away from a more intense south or west-facing window.

While it can tolerate lower light conditions, its growth may become slower and less dense. Avoid direct sunlight at all costs, as it will quickly scorch the delicate fronds, leaving them brown and crispy.

Indoors: Place in a well-lit room but out of the direct path of the sun’s rays. Outdoors: A shaded porch or patio where it is protected from direct sun is suitable in warm climates (Zones 10-12).

Signs of Incorrect Light

• Too much light: Scorched, brown, or faded pale green fronds.
• Too little light: Slow, leggy growth with sparse fronds as the plant stretches towards a light source.

How to Water a Fishtail Sword Fern

Consistent moisture is key for a happy Fishtail Sword Fern. The soil should be kept evenly moist, but never soggy or waterlogged, which can lead to root rot.

• Watering Frequency: Water thoroughly when the top inch of soil feels slightly dry to the touch. This could be about once a week, but adjust based on your home’s temperature and humidity.
• Water Type: Ferns can be sensitive to chemicals in tap water. Using filtered, distilled, or rainwater is best to prevent mineral buildup and leaf tip burn.
• Winter Care: Reduce watering slightly during the fall and winter when the plant’s growth slows down, but do not let the soil dry out completely.

Troubleshooting Water Issues

• Overwatering: Yellowing fronds, a mushy base, and wilting are signs of too much water. Ensure the pot has proper drainage.
• Underwatering: Wilting fronds that feel dry and crispy, along with brown leaf edges, indicate the plant is too dry.

Best Soil for Fishtail Sword Fern

Fishtail Sword Ferns need a potting mix that is rich in organic matter, retains moisture, but also drains well to prevent root rot. A standard peat-based potting mix is an excellent starting point.

To create an ideal blend, you can mix:

• 2 parts peat moss or coco coir
• 1 part perlite or orchid bark (for aeration)
• 1 part compost or other organic matter

This combination will provide the slightly acidic, airy, and moisture-retentive environment this fern loves. Ensure any pot you use has drainage holes at the bottom.

How to Feed a Fishtail Sword Fern

Fishtail Sword Ferns are not heavy feeders, but they benefit from regular nutrients during their active growing season (spring and summer).

• Fertilizer Type: Use a balanced, water-soluble fertilizer (e.g., 10-10-10 or 20-20-20).
• Application: Dilute the fertilizer to half the recommended strength to avoid burning the sensitive roots.
• Frequency: Feed the plant every 4-6 weeks throughout the spring and summer.
• Dormancy: Do not fertilize in the fall and winter, as the plant’s growth naturally slows down.

Ideal Temperature Range

The Fishtail Fern prefers average to warm household temperatures, typical of its native tropical habitat.

• Ideal Range: Keep temperatures between 60-75°F (16-24°C).
• Warning: It is not frost-tolerant. Protect it from temperatures below 55°F (13°C) and sudden drafts from windows, doors, or air conditioning vents, which can stress the plant.

Humidity Requirements for Fishtail Sword Ferns

High humidity is crucial for keeping a Fishtail Sword Fern lush and healthy. It thrives in humidity levels of 50% or higher. Dry air is one of the most common reasons for brown, crispy fronds.

How to Increase Humidity:

• Misting: Mist the fronds with water several times a week.
• Pebble Tray: Place the pot on a tray filled with pebbles and water. The evaporating water will increase ambient humidity.
• Humidifier: Running a small humidifier nearby is one of the most effective methods.
• Grouping Plants: Place it near other plants to create a humid micro-environment.
• Location: Bathrooms and kitchens are naturally more humid and make great homes for ferns.

Does the Fishtail Sword Fern flower?

Pests That May Affect Fishtail Sword Ferns

The upright, dense habit and uniquely forked leaflets of the Fishtail Sword Fern can provide excellent cover for pests, making early detection a challenge. It’s wise to inspect the plant’s crown and the undersides of its fronds regularly.

• Spider Mites - A common problem in dry indoor conditions. These tiny pests create fine webs and cause the foliage to look dusty, faded, and generally unhealthy.
• Mealybugs - These sap-sucking insects appear as white, fuzzy spots, often clustered deep in the plant’s crown or where the fronds emerge from the soil.
• Scale Insects - Look for hard, brown, immobile bumps along the central stems (rachis) of the fronds. They can blend in, so careful inspection is needed.
• Fungus Gnats - The need for consistently moist soil makes this fern a prime target for fungus gnats, whose larvae live and feed on organic matter and fine roots in the soil.
• Whiteflies – Tiny, moth-like insects that fly up in a cloud when the plant is disturbed. They cluster on the undersides of leaves to suck sap, leading to yellowing and sticky residue. Use yellow sticky traps and insecticidal soap to control them.

Isolate an infested fern and treat with horticultural soap, paying close attention to get the spray into all the dense areas of the plant.

Outdoor Pest Concerns

If grown on a shaded patio or in a frost-free garden, the Fishtail Sword Fern may encounter:

• Slugs & Snails - These will chew holes in the fronds, especially in damp weather.
• Caterpillars - Can cause noticeable chewing damage to the unique “fishtail” leaflets.

Troubleshooting Fishtail Sword Fern Issues

Like other Nephrolepis ferns, the Fishtail Sword Fern’s health is directly linked to high humidity and proper watering. Most problems are a signal that one of these environmental factors is off.

• Brown, Crispy Edges - This is the most common issue and is almost always caused by air that is too dry. The forked “fishtail” tips are particularly susceptible to drying out and turning brown.
• Leaf Drop - When this fern is stressed, especially from its soil drying out completely, it will shed its leaflets in protest. This is a cry for more consistent watering.
• Yellowing Leaves - This points to a watering problem. Check the soil: if it’s constantly wet, the fern is being overwatered. If the soil is dry and the fronds are pale yellow, it needs water.
• Wilting & Drooping - The fronds will sag when the plant is thirsty. However, if the soil is wet and the plant is still limp, it’s a critical sign of root rot, where the damaged roots can no longer function.
• Pale or Faded Leaves - If the rich green color looks washed-out, the fern is receiving too much direct sunlight. Move it to a spot with bright, indirect light to prevent scorching.
• Leggy Growth - Long, weak, and sparse fronds indicate the plant isn’t getting enough light to support lush, compact growth. While it needs shade from direct sun, it still requires plenty of bright, ambient light.
• Sunburn or Leaf Scorch – Appears as large, bleached, white, or crispy brown patches on leaves exposed to too much direct sunlight. This is damage from intense light and heat, not a disease.
• Nutrient Deficiency – Can manifest as slow or stunted growth, pale or yellowing leaves, and a general lack of vigor. It indicates the plant has exhausted the available nutrients in its soil and requires feeding with a balanced fertilizer.

Propagating Your Fishtail Sword Fern

Propagating a Fishtail Sword Fern is relatively easy and is best done in the spring. There are two primary methods:

1. Division: This is the most common method. When repotting a mature, crowded plant, gently separate the root ball into two or more sections. Ensure each new section has a healthy portion of roots and several fronds. Pot each division into its own container with fresh soil and keep it warm, humid, and well-watered until it establishes.

2. Runners (Stolons): Healthy Fishtail Sword Ferns will send out long, fuzzy runners, or stolons. You can pin a section of a runner (with a small node) down into a separate pot of soil while it’s still attached to the mother plant. Once it develops its own roots, you can snip it free.

Is the Fishtail Fern toxic to cats and dogs?

Why are the tips of my Fishtail Fern turning brown and crispy?

How can I make my Fishtail Fern look fuller?

Does the Fishtail Fern need a lot of sun?