I have killed more Duckweed than I care to admit, usually by overthinking the light and underwatering the root zone at the same time. The Lemna minor Duckweed is a workhorse plant for a reason: it tolerates a wide range of conditions and still looks good doing it.
At a glance
| Light | high |
|---|---|
| Temperature | 22 to 28 °C |
| pH | 6.0 to 7.5 |
| Height | 1 to 3 cm |
| CO₂ | not required |
| Growth | very fast |
Planting
Plant Duckweed with the crown or rhizome clear of the substrate — burying it rots the base. In a 34-gallon tank, position it mid-ground or background depending on its height. Weaker setups do fine; pair it with our planaria guide guide for a layered look.
Light and CO₂
Run 8 hours of light a day on a timer to avoid algae swings. Duckweed grows under high light and not required, though a small, steady dose of liquid fertiliser every 4 weeks pushes denser growth.
Propagation
It multiplies by budding; thin it weekly to stop coverage.
Common issues
Yellowing lower leaves usually mean a nutrient gap, not too little light. Trim dying leaves at the base, keep nitrates around 10 to 20 ppm, and avoid moving the plant every week — a solid internal nematodes in a planted tank explains why stability beats tinkering.
Why it suits beginners
The Duckweed tolerates the small mistakes new aquarists make: missed water changes, uneven light, the occasional algae bloom. Keep the crown above the substrate and do not move it every week.
