How much light does Java Fern need?

Low light, around 15–30 µmol·m⁻²·s⁻¹ of PAR. Watts are not comparable between fixtures; PAR is. If the manufacturer does not publish PAR, pick one band lower than the tank depth suggests.

Does Java Fern need CO₂?

It is optional. Marked "optional": with CO₂ it grows faster and tighter, without it still does fine.

What water does Java Fern want?

22–28 °C, pH 6–7.5, 2–12 dGH. At 10 dGH wide it is one of the more forgiving ranges.

How fast does Java Fern grow, and where does it go?

Growth rate: slow. Placement: midground / attached. Substrate: no substrate needed, reaching about 15–30 cm. Difficulty: beginner.

G-02 / 01Freshwater

Java Fern爪哇蕨

Microsorum pteropus · Polypodiaceae

The most shade-tolerant of the tied-on plants; bury the rhizome and it rots.

Illustration to come

G-02 / 01 · Java Fern Microsorum pteropus

SpecificationsPlant atlas

Name: 爪哇蕨
Scientific name: Microsorum pteropus
Family: Polypodiaceae
Origin: Streams and riverbanks of Southeast Asia (Malaysia, Indonesia, Thailand)
Light: Low light
PAR: 15–30
CO₂: Optional
Hardness: 2–12 dGH
Growth: Slow
Placement: Midground / Attached
Substrate: No substrate needed
Height: 15–30 cm
Level: Beginner

Water requirementsFreshwater

Temp.22–28 °C

pH6–7.5

Hardness2–12 dGH

Alkalinity1–8 dKH

Units: temperature in °C, hardness in German degrees (dGH / dKH), marine salinity as specific gravity at 25 °C, volume in litres. These are the values recorded for the species and do not follow the site unit switcher.

Growing notes

1Tie the rhizome to driftwood or lava rock with cotton thread or fishing line and cut the line after two or three weeks once the roots grip; the rhizome itself must stay in open water.
2Six to eight hours of light a day is plenty, and stronger light with weaker flow brings more black brush and green spot algae on the older leaves.
3Potassium shortage punches holes in the leaves and iron shortage yellows the new growth; tied-on plants feed from liquid fertiliser in the water, not from the substrate.
4It spreads along a creeping rhizome, and a daughter plant with three to five leaves can be cut away and tied elsewhere.
5Growth stops above 30 °C for long periods, so ventilate in summer and keep it out from directly under the light.

Frequently asked questions

How much light does Java Fern need?: Low light, around 15–30 µmol·m⁻²·s⁻¹ of PAR. Watts are not comparable between fixtures; PAR is. If the manufacturer does not publish PAR, pick one band lower than the tank depth suggests.
Does Java Fern need CO₂?: It is optional. Marked "optional": with CO₂ it grows faster and tighter, without it still does fine.
What water does Java Fern want?: 22–28 °C, pH 6–7.5, 2–12 dGH. At 10 dGH wide it is one of the more forgiving ranges.
How fast does Java Fern grow, and where does it go?: Growth rate: slow. Placement: midground / attached. Substrate: no substrate needed, reaching about 15–30 cm. Difficulty: beginner.