Wabi-kusa: how to make and grow an emersed plant ball
A wabi-kusa is a ball of aquarium soil planted with aquatic plants grown emersed — leaves in humid air, roots in wet soil — and shown in a shallow glass dish of water or later dropped into an aquarium. It comes from Aqua Design Amano, needs no CO₂ while emersed, and wants about 8–10 hours of bright light a day.
| Difficulty | Easy; the main risk is drying out |
|---|---|
| Ball size | About 7–10 cm, roughly a tennis ball |
| Container | Shallow glass bowl about 15–25 cm wide, or a covered glass vessel |
| Light | 8–10 h of bright window or LED light; no harsh direct sun |
| Humidity | High — mist 2–3 times a day in dry rooms, or use a cover |
| CO₂ | Not needed emersed; recommended once submerged in a planted tank |
| Typical plants | Rotala, dwarf hairgrass, Glossostigma, HC 'Cuba', Staurogyne, mosses |
| Share of published layouts | 20 of 591 in MOKIZEN's analysis |
What is wabi-kusa?
Wabi-kusa is a product and a technique from Aqua Design Amano (ADA), the Japanese company founded in 1982 by Takashi Amano (1954–2015), creator of the Nature Aquarium style. The name joins 'wabi', from the Japanese taste for quiet, imperfect beauty, with 'kusa', meaning grass or plants. Gensou renders it loosely as a 'rustic, humble landscape'. Sources differ on the credit — Gensou says Amano developed it, Botachoku that ADA popularised it — but both lead back to ADA. None of the sources we checked gives the year it was launched.
ADA sells ready-grown balls in several lines, including foreground carpet plants such as Hemianthus callitrichoides, Glossostigma, Utricularia graminifolia, Eleocharis acicularis and a Micranthemum. They need no planting work: set one on the substrate, the roots stay undisturbed and new shoots establish quickly, which is how Amano planted large layouts efficiently. In MOKIZEN's analysis of 591 published layouts, 20 are wabi-kusa.
How does a wabi-kusa grow without CO₂?
Because the leaves grow emersed, in humid air, they take CO₂ straight from the atmosphere, so no injection is needed. Only the lower part of the ball stands in water; the top and the leaves depend on high humidity. It is meant to be a living, changing piece in the wabi-sabi spirit — trim towards a pleasing natural shape, not a perfect sphere.
Which plants can you use for wabi-kusa?
Use aquatic plants that grow both above and under water. Fast, dense growers — stem plants, carpeting plants and hairgrass — cover the ball quickly; mosses and slow epiphytes can be added for texture.
| Role | Plants |
|---|---|
| Height | Rotala, e.g. R. rotundifolia |
| Grass tuft | Dwarf hairgrass (Eleocharis acicularis) |
| Carpet | Glossostigma elatinoides, Hemianthus callitrichoides 'Cuba', Micranthemum, Utricularia graminifolia |
| Low bush | Staurogyne repens |
| Filler / accent | Hydrocotyle tripartita, Hygrophila pinnatifida, Bucephalandra |
| Wrap / cover | Mosses such as Taxiphyllum or Fissidens |
How do you make a wabi-kusa ball step by step?
Mix aquasoil with clay so the ball holds together. Sources give slightly different ratios — Botachoku uses 7:3 aquasoil to clay, Gensou 3:1 soil to bentonite clay (and also allows potting soil) — both simply mean mostly soil with enough clay to bind. Gensou wraps the ball in 5–8 mm of sphagnum, while Botachoku ties the plants straight into the soil; aquatic mosses also work as a living cover.
- Knead aquasoil, clay and water until it holds, then press a firm ball of about 7–10 cm; add enough water to avoid fine cracks.
- Optionally wrap the ball in a thin layer of moss.
- Push small portions of each plant into the ball.
- Bind everything with cotton thread, which slowly rots away, or fishing line, wound in several directions.
- Stand the ball in a shallow dish with roughly the lower third in water.
- Put it in bright light and keep the air humid by misting or with a cover.
- Optionally, after about 3–4 weeks of emersed growth, move it into an aquarium away from strong flow.
How often do you mist and water a wabi-kusa?
In a dry room, mist the leaves about 2–3 times a day and refresh the dish every 2–3 days. Botachoku changes the dish water on that schedule; Gensou only tops it up and relies on Singapore's high room humidity instead of misting. If your room is dry or air-conditioned, follow the misting routine or use a glass cover; if it is naturally humid, topping up may be enough. Changing the water rather than only topping up also helps keep mould and algae off the ball.
| How often | Task |
|---|---|
| Daily | Mist 2–3 times in dry rooms |
| Every 2–3 days | Top up or replace the dish water |
| Weekly | Optional weak, about quarter-strength liquid fertiliser |
| Every 2–3 weeks | Trim to shape and remove yellow or dead leaves |
What light and container does a wabi-kusa need?
Give it about 8–10 hours a day of bright light from a window or an LED, but avoid harsh direct sun. The ball itself is the composition, so no hardscape is needed. Show it in a shallow glass bowl about 15–25 cm wide, or in a covered glass vessel that holds humidity — ADA's DOOA brand, for example, sells Neo Glass Air containers with matching glass lids. There is no filter; the dish water is simply replaced or topped up.
Why do the leaves melt when you put a wabi-kusa in an aquarium?
The emersed leaves often die back underwater because the plant is switching to new submersed leaves — this is normal adaptation, not failure. Leave it alone and the underwater growth follows. Place the ball in a calm spot, because strong flow can wash the soil apart, and consider CO₂: it is not needed above water but is recommended for vigorous growth once submerged in a planted tank. Once in the aquarium it simply joins the tank's normal community; the dish form holds no animals.
What are common wabi-kusa mistakes?
Most problems come down to moisture: too little air humidity, or water left standing too long.
- Letting it dry out: emersed leaves shrivel fast without humid air. Mist, cover the vessel and keep the dish topped up.
- Stagnant water and still, humid air: mould and algae grow on the ball. Change the dish water every few days and allow some air exchange.
- Too dry a soil mix when forming: the ball cracks and falls apart. Add enough water and clay.
- Dropping it straight into a strong current: the flow washes the ball apart. Choose a calm spot.
- Panicking when leaves melt after submerging: the plant is making underwater leaves. Wait.
Plants and animals in this guide
- Dwarf Hairgrass (Eleocharis) (Eleocharis pusilla (sold as E. parvula / 'Mini') / E. acicularis)
- Glossostigma (Glossostigma elatinoides)
- HC Cuba (Hemianthus callitrichoides) (Hemianthus callitrichoides 'Cuba' (now Micranthemum callitrichoides))
- Utricularia graminifolia (UG) (Utricularia graminifolia)
- Rotala H'ra (Rotala rotundifolia 'H'ra')
- Staurogyne repens (Staurogyne repens)
- Hygrophila pinnatifida (Hygrophila pinnatifida)
- Hydrocotyle tripartita ('Japan') (Hydrocotyle cf. tripartita ('Japan'))
- Bucephalandra (Buce) (Bucephalandra spp.)
- Fissidens Moss (Phoenix Moss) (Fissidens fontanus)
Related guides
- Nature Aquarium style: layout rules and setup
- Riparium: a riverbank tank with plants above the water
- Closed terrarium: how to build one that lasts
- Balancing light, CO₂ and fertiliser in a planted tank
Sources
- WABI-KUSA lineup — Aqua Design Amano (ADA)
- Wabi-kusa foreground plants — Aqua Design Amano (ADA)
- Wabi-Kusa — Aquascaping Wiki — Aquasabi
- Wabi-kusa DIY guide — Botachoku (Japan)
- Wabi-kusa step by step: emersed moss ball aquascape — Gensou Premium Aquascaping (Singapore)
- NEO GLASS AIR — DOOA / Aqua Design Amano
- Takashi Amano — Wikipedia
- Wabi-sabi — Wikipedia
- About emersed production of aquarium plants — Tropica Aquarium Plants
- Aquascape insights (591 published layouts) — MOKIZEN
Written from these sources; last updated .
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