Water lettuce, or Pistia stratiotes, is a floating aquatic plant with rosettes of green, serrated leaves. It's also known as water cabbage and Nile cabbage. It's a popular addition to aquariums and outdoor ponds because of its lush foliage and its role in improving water quality. In temperate climates, water lettuce can be cultivated outdoors year-round. But in colder climates, you may have to over winter the plant to keep it alive.
Where to Grow Water Lettuce
Water lettuce can be grown outdoors in full sunlight in temperatures above 70 degrees F. It can also be grown indoors in an aquarium, although it needs more maintenance than other aquatic plants. The water temperature should be between 68 and 82 degrees F. Water lettuce absorbs the nutrients it needs from the water and doesn't need to be fertilized like other aquatic plants.
Over Wintering Water Lettuce
Water lettuce is a warm weather plant and can't survive temperatures below 50 degrees F. If you live in a cold climate, you'll need to over winter the plant if you want to keep it alive. There are two methods of over wintering water lettuce. The first is to bring it indoors in an aquarium or pond. The second is to put the plant in a bucket of water and store it in a cool, dark place such as a basement or garage.
Bringing Water Lettuce Indoors
If you decide to bring your water lettuce indoors, you'll need to make sure the aquarium or pond has the right conditions for the plant to survive. The water should be between 68 and 82 degrees F and the light should be kept at a low level. You'll also need to make sure the water lettuce is in a location where it won't freeze or be exposed to cold drafts.
Storing Water Lettuce Outdoors
If you decide to store your water lettuce outdoors, you'll need to choose a location that's cool and dark. A basement or garage is ideal. Place the water lettuce in a bucket of water and make sure it's completely submerged. Place a lid or tarp over the bucket to keep out light and cold air. The water lettuce should be checked periodically to make sure the water level hasn't dropped and the temperature hasn't gone below 50 degrees F.
Caring for Water Lettuce
If you decide to keep your water lettuce indoors, you'll need to maintain the water quality and temperature. Change the water regularly, and add a dechlorinator or water conditioner if necessary. You'll also need to make sure the water lettuce is getting enough light. If the leaves start to turn yellow, you'll need to move it to a brighter spot.
Harvesting Water Lettuce
If you're keeping water lettuce outdoors, you may want to harvest some of the leaves at the end of the season. The leaves can be used in salads or cooked like spinach. Harvesting some of the leaves will also help keep the plant from becoming overcrowded and will help it survive the winter. When the temperature starts to drop, you should stop harvesting the leaves and let the plant go dormant.
Conclusion
Water lettuce is a beautiful addition to aquariums and outdoor ponds, but in cold climates, you may need to over winter the plant to keep it alive. There are two methods of over wintering water lettuce. You can bring it indoors in an aquarium or pond, or you can store it in a bucket of water in a cool, dark place. Make sure to check the water lettuce periodically to make sure it's not exposed to cold drafts or freezing temperatures. With proper care, you can enjoy your water lettuce year-round.