The worm fern, or Blechnum brasiliense, is a captivating plant known for its striking appearance and tropical aesthetic. Its arching, finely divided fronds offer a lush, feathery texture, often emerging with a vibrant reddish hue before maturing into a deep, glossy green. Over time, this fern develops a distinctive trunk-like base, earning it common names like Brazilian Tree Fern, Red Brazilian Tree Fern, and Red Dwarf Tree Fern. It also purifies the air, making it a functional and beautiful addition to homes.
Worm Fern Care Essentials
Light Needs
The worm fern prefers bright, indirect light or dappled shade, mimicking its native understory habitat. Indoors, place it near an east or north-facing window or use a sheer curtain to diffuse sunlight. Avoid direct, harsh midday sun, as it can scorch fronds, causing them to become pale or marked. Consistent light levels support healthy foliage development.
Watering Techniques
Maintain consistent soil moisture; the fern dislikes drying out completely. The soil should remain moist but never waterlogged to prevent root rot. A good practice is to water the plant when the top layer of soil begins to feel dry to the touch. Use de-chlorinated water, as chlorine can harm houseplants.
Soil Requirements
This fern prefers well-draining, loamy soil rich in organic material that retains moisture. An ideal blend often includes peat, perlite, and compost, which provides good aeration and drainage while supplying necessary nutrients. It prefers slightly acidic soil (pH around 5.5).
Temperature and Humidity
Worm ferns prefer moderate temperatures, ideally between 68 to 75.2°F (20-24°C). In cooler months, temperatures should not fall below 53.6°F (12°C). High humidity is important, with optimal levels around 80% and a minimum of 50%. To increase humidity, place the plant on a humidity tray, group it with other plants, or use a room humidifier. While misting can offer a temporary boost, it is generally less effective for sustained humidity.
Fertilization
During its active growing season (spring and summer), fertilize regularly. Apply a balanced liquid fertilizer (e.g., 10-10-10), diluted to half or one-third strength, monthly. It is advisable to reduce or cease fertilization during the winter months when the plant’s growth naturally slows. Over-fertilization can harm the plant, so adhere to dilution rates.
Propagating Worm Ferns
Worm ferns can be propagated by spores or division. Spore propagation, though requiring patience, yields many new plants. To propagate by spores, collect the tiny, brown spore cases (sori) from the underside of mature fronds, then dry them to release the spores. Sprinkle these fine spores onto a sterile, moist growing medium, such as a mix of peat moss and perlite, in a shallow tray. Covering the tray with a clear plastic dome or glass helps maintain the high humidity needed for germination, which can take several weeks or months in indirect light.
Division offers a faster approach, especially in spring or early summer. Carefully separate offsets or rhizome sections from the main plant. Each section, ideally with roots and foliage, can be planted in its own pot. While quicker, new plants may take time to establish.
Troubleshooting Common Worm Fern Problems
Worm ferns can develop issues from environmental factors. Browning leaves or crispy tips often result from insufficient humidity, inconsistent watering, or too much direct sunlight. Increase humidity, maintain consistent soil moisture, and adjust light. Removing affected fronds can encourage new growth.
Root rot (soggy soil, mushy roots) results from overwatering or poor drainage. Reduce watering, ensure adequate drainage, and repot with fresh soil if severe. Stunted growth or yellowing leaves may indicate nutrient deficiency, remedied by regular fertilization during the growing season. Pests like scale insects, mealybugs, and spider mites may appear, especially in dry conditions. Manage them by manual removal, insecticidal soap, or neem oil.
Worm Fern Toxicity
The worm fern (Blechnum brasiliense) is considered non-toxic to humans and pets. While severe reactions are not known, keep all houseplants out of reach of children and pets. Ingesting any plant material can sometimes cause mild gastrointestinal upset.