How to grow Java fern (Microsorum pteropus)

The Java fern is native to various parts of Asia and has long been a mainstay of the hobby. It grows emersed in moist forests, but can also be found completely submerged in some places. Java fern is a rhizomatous plant with dark green leaves growing along a creeping rhizome. As there are many varieties of this plant, the leaves can be of different lengths and pinnate. The most common variety has leaves as long as a hand and about an inch wide. Its leaves have a unique hammered pattern when examined closely.

Some common variants of Java fern/Microsorum pteropus:

Microsorum pteropus 'needle leaf' - Thin (1-2cm), but longer leaves (up to 30cm)

Microsorum pteropus 'Philipine' - Smaller varietal, shorter leaves around palm length 

Microsorum pteropus 'short narrow leaf' - Smaller, more compact varietal

Microsorum pteropus 'orange' - Orange tips in younger leaves

Microsorum pteropus 'Trident' - Leaves have 2 to 5 lobes on each side

Microsorum pteropus 'Thors hammer' - Split end leaves

Microsorum pteropus 'Windelov' - 10 to 20cm, tip splits into many lobes

Microsorum pteropus 'Trident' has lobed leaves.

Java fern is one of the hardiest plants in the hobby, tolerating low light and a wide range of water conditions. It does not need to be planted in the ground to grow well - it can be attached to hardscape for easy repositioning. It can be secured to rock or wood using string, zip ties or superglue. If superglue is used, gel superglue (ethyl cyanoacrylate) is easier to work with. These plants can also be glued directly to hardscape underwater - apply the glue to the rhizome or root mass, then press against the hardscape and hold for about 15 seconds until it adheres. Over time the root mass will naturally adhere to the hardscape;

However, contrary to popular literature, it can be grown (planted) on top of the substrate as long as the rhizome itself is not buried. Its roots can and will draw nutrients from the substrate.

Java fern can be grown planted on the substrate. In the wild it grows on moist soils along the edges of water bodies.

In most aquariums, it will grow and reproduce on its own without any special care - taking available nutrients from the water (nutrients that are present in tap water or fish waste by-products). In some tanks, the lack of critical nutrients will cause blackening and deterioration over time. Due to their slow growing nature, they will not show signs of nutrient deficiency for many weeks. Regular dosing of a complete liquid nutrient into the aquarium water will ensure long-term health.

Like many other plants, Java fern prefers some current. However, as a slower grower it can be more susceptible to BBA if placed in the path of too strong or too turbulent a current. If you find that Java ferns in the path of the current are the only ones to get BBA, consider moving them or changing the flow pattern in the tank to be more gentle.

Java fern is popular for low tech/non-CO2 injected tanks as it will grow well without carbon dioxide injection or power lights. It will grow faster and thicker with healthier leaves when CO2 injection is provided.

Key success factors

• Clean, filtered water prevents algae issues

• Overall tank stability important for long term health

• Vulnerable to low potassium water; for long term health, comprehensive set of nutrients should be provided

• Poor water quality/nutrient access leads to blackening of leaves

Propagation

Java fern will naturally produce daughter plants on mature leaves when growth conditions are favourable. These baby plants can be detached and replanted when they reach a suitable size (about an inch or so).

Longer rhizomes can be divided with scissors or by hand. Be sure to leave a few healthy leaves on each segment of the rhizome.