Water lettuce provides a floating rosette of attractive foliage that resembles lettuce. The plants float in ponds and water features, forming dense clumps of leaves. The leaves remain dry while the long roots dangle freely in the water. The plants shade the water and the floating roots leach nutrients from the pond, which helps prevent algae growth. Water lettuce grows naturally as a tropical perennial. In colder climates, grow the plant as an annual or bring it indoors to overwinter.
Things You'll Need
- Plastic mesh or hoop
- Grow lights
Partition off a section of the pond for the water lettuce, as water lettuce prefers crowding. Use clear plastic mesh formed into a cylinder or a floating hoop to create the water lettuce section.
Float the plants inside the mesh or plastic hoop. Set the plants so the feathery roots trail under the water and the rosette of leaves floats on top of the water. Insert enough plants inside the hoop so they float freely but the leaves touch each other.
Fill a bucket with water to fertilize the lettuce in midsummer. Add a soluble pond fertilizer to the bucket of water at the rate recommended on the label. Remove the lettuce from the pond and float the plants in the bucket of water for 24 hours to fertilize them. Repeat the fertilization procedure six weeks later.
Bring water lettuce indoors for winter, as they can't tolerate frost. Float the plants in a bucket of water in a warm room where they receive six hours of bright sunlight. Alternatively, set a grow light 6 inches above the plants and leave it on for 10 to 12 hours a day.
Tips & Warnings
- You can add pond fertilizer directly to the pond if you have a lot of lettuce, but it may cause a temporary algae bloom.
- Fish hide in and feed upon water lettuce roots. If the fish overeat the lettuce, block access to the roots with a plastic mesh cylinder.
- Water lettuce is considered an invasive water plant in many areas and should only be grown in ponds and water features that do not connect to natural waterways.
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