Wolffia arrhiza, commonly known as watermeal duckweed, is the smallest flowering plant on Earth. This free-floating aquatic plant is an excellent source of protein and is gaining attention as a sustainable food option. Growing Wolffia arrhiza at home is surprisingly simple and requires minimal space, making it an ideal choice for hobbyists or those interested in home aquaponics.
Choosing the Right Container and Environment
Start by selecting a shallow, wide container—such as a tray or aquarium—that can hold 3–6 inches of water. Since Wolffia floats on the water surface, surface area is more important than depth. Place the container in a spot that receives indirect sunlight or use a full-spectrum LED grow light for 12–14 hours a day. Wolffia thrives in warm temperatures, ideally between 20°C and 30°C (68°F to 86°F).
Preparing the Water
Use dechlorinated tap water or rainwater to fill the container. Tap water should be left out for 24–48 hours or treated with a dechlorinator to remove harmful chemicals. Maintain a slightly acidic to neutral pH (around 6.5–7.5) for optimal growth. To provide nutrients, add a diluted liquid aquatic plant fertilizer—start with one-quarter of the recommended dosage to avoid overfeeding and algae blooms.
Introducing and Maintaining Wolffia arrhiza
Once the water is prepared, gently introduce the Wolffia onto the surface. It reproduces by budding, so even a small quantity can multiply rapidly under good conditions. Stir the water gently every few days to prevent clumping and ensure even light exposure.
Monitor for pests like mosquitoes and algae. If algae become a problem, reduce light exposure slightly and consider adding a few snails or using a biological control like barley straw extract.
Harvesting and Uses
Wolffia can double in biomass every 2–3 days under optimal conditions.
With a bit of care, growing Wolffia arrhiza at home can be a rewarding and sustainable experience.
