The Austral Gem Fern (Asplenium dimorphum x difforme) is a popular houseplant, especially for those new to fern care. This hybrid fern, originating from Australia, features thick, waxy, dark green fronds that give it a unique appearance. Unlike many other ferns, its robust nature and adaptability make it a forgiving option for indoor environments, contributing to its widespread appeal.
Key Care Requirements
Light
The Austral Gem Fern thrives in indirect light. Medium to bright indirect light is ideal, though it tolerates lower light, making it suitable for various indoor settings. Avoid direct sunlight, which can scorch fronds. Insufficient light may cause stunted growth, while too much sun can lead to leaf burn.
Watering
Water the Austral Gem Fern when the top inch of soil feels dry to the touch, or when a moisture meter indicates a reading of four. While somewhat drought-tolerant due to its waxy leaves, prolonged dryness should be avoided, as fronds may droop but often recover after watering. Overwatering can lead to root rot, so ensure proper drainage.
Humidity
This fern prefers moderate to high humidity, ideally between 45% and 65%. While it tolerates average household humidity, higher levels promote healthier growth. To increase humidity, methods include placing the plant on a pebble tray filled with water, grouping it with other plants, or using a room humidifier. Misting also offers a temporary boost.
Temperature
The Austral Gem Fern thrives in daytime temperatures between 65°F and 75°F (18°C and 24°C), with nighttime temperatures around 60°F. Consistent temperatures are beneficial, as significant fluctuations can cause yellowing and drooping fronds. Protect the plant from cold drafts and temperatures below 50°F (10°C).
Soil
The right soil mix is essential for both moisture retention and adequate drainage. A well-draining potting mix rich in organic matter is recommended. Peat-based mixes or those containing coco coir, pumice, or perlite are suitable. This type of substrate offers good aeration while retaining some moisture, helping prevent waterlogging detrimental to root health.
Fertilizing
Fertilize sparingly, as the Austral Gem Fern is not a heavy feeder. During the growing season (spring and summer), apply a diluted, balanced liquid fertilizer monthly. Dilute the fertilizer to half its recommended strength to prevent over-fertilization, which can cause brown leaf tips. Reduce or stop fertilization during fall and winter.
Ongoing Maintenance
Repotting
Repotting is typically needed when the plant becomes root-bound or outgrows its container, usually every one to two years. The best time is during spring or mid-summer. Choose a new pot only slightly larger than the previous one to avoid overwatering. Repot gently to minimize root shock, using a well-draining organic potting mix.
Pruning
Pruning requirements are minimal, as the plant maintains an attractive shape naturally. Remove any dead, yellowing, or damaged fronds by clipping them at the base. This simple maintenance helps the fern direct energy towards new, healthy growth and maintains its appearance.
Addressing Common Problems
Browning Leaf Tips or Edges
Browning leaf tips or edges often indicate issues with humidity or watering consistency. Low humidity can dry out fronds, while inconsistent watering (allowing soil to dry too much) also contributes. Ensure a consistent watering schedule and increase ambient humidity to mitigate this.
Yellowing Fronds
Yellowing fronds can signal several issues. Overwatering is a common cause, as soggy soil leads to root rot. Nutrient deficiencies may also cause yellowing, indicating a need for fertilization. Sometimes, yellowing is a sign of natural aging, where older fronds at the base decline.
Pests
While robust, the Austral Gem Fern can encounter common houseplant pests.
Spider mites may cause speckling and fine webbing.
Mealybugs appear as small, white, cottony masses.
Scale insects are small, oval, or round bumps on plant surfaces.
Organic treatment methods include wiping affected areas with rubbing alcohol or applying insecticidal soap or neem oil.
Stunted Growth
Stunted growth may point to environmental factors. Insufficient light hinders photosynthesis, leading to slower growth. Nutrient issues, such as lack of fertilization, can also limit growth. Root problems, often from overwatering or being severely root-bound, impede nutrient and water uptake, resulting in poor development.