Hydroponic Java Fern: Rhizomes on Wood or in Jars of Water
A hydroponic java fern is Microsorum pteropus grown with its rhizome resting on wood or rock in water instead of soil. The fern spreads by runners that set new daughter plants, so one jar can turn into several over time.
The short answer
UF/IFAS Extension lists java fern among freshwater plants that spread by runners with daughter plants along them. Set the rhizome on wood or rock in a jar of water, give it shade rather than full sun plus clip off daughter plants to start new jars. Avoid heavy fertilizer to limit algae.
What is java fern?
UF/IFAS Extension groups java fern with plants such as dwarf hairgrass plus eelgrass that make rhizomes or stolons. These root like stems grow in or on the substrate. Such stems also anchor the plant, UF/IFAS notes.
NC State Extension describes a rhizome as a modified stem that grows sideways near the surface. It stores food plus serves as a means of propagation. Ferns also differ from seed plants. NC State notes ferns reproduce by spores, not seeds.
How do you set java fern on wood?
No source here gives a method for tying java fern to wood. The sources do cover how aquatic plants are held in place. UF/IFAS notes rhizomes plus stolons anchor plants to the substrate. Colorado State University Extension notes larger rocks set around a potted aquatic plant stop it from shifting before it roots in.
Rest the rhizome on the wood or stone so it sits on the surface rather than under gravel. Wedge a stone beside it until roots grip.
| Item | What to do | Source |
|---|---|---|
| Rhizome | Rest it on wood or rock | UF/IFAS plus NC State |
| Hold in place | Set stones around it until it roots | Colorado State |
| Light | Shade, not full sun | Iowa State |
| Water | Low in nutrients to limit algae | UF/IFAS |
| New plants | Clip daughter plants off the runner | UF/IFAS |
Source: UF/IFAS Extension, NC State Extension, Colorado State University Extension plus Iowa State University Extension.
How does java fern make new plants?
UF/IFAS Extension notes that along runners new daughter plants form plus grow. Producers often clip daughter plants straight from the parent runner plus place them in new pots or tanks. Large clumps can also be split from the parent.
Iowa State University Extension notes division is the most reliable way for home gardeners to propagate ferns. Ferns with creeping rhizomes can be cut into sections 2 to 3 inches long that hold both roots plus shoots.
How to: step by step
- Rinse the plant plus remove any pot or wool.
- Find the green rhizome along the base.
- Rest the rhizome on wood or rock.
- Set stones beside it so it stays put.
- Place the jar in shade out of direct sun.
- Clip off daughter plants once they root.
Troubleshooting
Yellow fronds: too much light. Iowa State notes intense light turns fern fronds yellow plus short. Move the jar to shade.
Long spindly fronds: too little light. Low light makes fronds stretch, Iowa State notes. Move the jar closer to a window.
Green film in the jar: extra nutrients. UF/IFAS notes high nutrient levels cause algae to bloom. Use low nutrient water plus avoid overfertilizing.
For more on root media see hydroponic in different mediums plus caring for your hydroponic system. Read aquarium water for cannabis. Kind Seed Co also stocks cannabis seeds.
Sources
- Freshwater ornamental aquatic plant production in Florida (FA251), UF/IFAS Extension
- Water gardens: planting aquatic plants (PlantTalk 1026), Colorado State University Extension
- Extension Gardener Handbook, chapter 3: botany, NC State Extension
- Growing ferns in Iowa, Iowa State University Extension, Yard and Garden
FAQ
Does java fern need fertilizer in a jar?
UF/IFAS Extension notes some aquatic species need fertilizer added to the water while others get by on the trace nutrients already present. It also notes high nutrient levels cause algae blooms, so add very little to a small jar.
How do ferns reproduce?
NC State Extension notes ferns reproduce by spores rather than seeds. Iowa State University Extension adds that growing ferns from spores is slow plus hard, so home gardeners rarely do it. Division of the rhizome is the more reliable way to make new ferns.
What water should fill the jar?
UF/IFAS Extension notes municipal tap water has chemicals added that may hinder aquatic plant growth plus may lack needed nutrients.
What are daughter plants on java fern?
UF/IFAS Extension notes java fern spreads by runners, which are root like stems growing in or on the substrate. New daughter plants form along these runners. It is common to clip daughter plants from the parent runner plus place them in new pots or tanks.
How much light does java fern need?
Iowa State University Extension notes ferns prefer varying degrees of shade. Full sun can make the fronds of some species wilt. Intense light turns fronds yellow while too little light makes them long plus spindly. Fronds in the right light grow full size.
