If you live near a pond or watched animation movies, you probably saw small rosettes of green leaves floating on water with flowers hiding in them and frogs chillin’ on them. This plant is called Water Lettuce, and no, it has no relationship to the actual lettuce except in appearance.
Water lettuce doesn’t only can grow in ponds, but you can grow them indoors in tanks or aquariums to enjoy their delicate look. But beware! This soft and innocent-looking plant has a reputation for being evil. For example, did you know that it’s illegal to possess or grow water lettuce in some US states?
Continue reading this article to know what to look out for before growing water lettuce and maintaining growing them effectively in ponds, tanks and aquariums.
Table of Contents
- Scientific Name: Pistia stratiotes
- Order: Water plantains
- Family: Araceae
- Genus: Pistia
- Care Level: Medium
- Growth Rate: Fast
- Maximum Size: 11.8 in (30 cm) diameter and a height of 4 in (10 cm)
- Water Conditions: pH range of 6.5-7.5 and warm temperature of 72-86°F (22-27°C)
- Lighting: Medium
- Propagation: sexual (exceptional in aquariums) and asexual
- Tank Placement: place the tank near a window or under fluorescent grow lights
What Is Water Lettuce?
Water Lettuce (also known as Water Cabbage and Nile cabbage) is a tropical aquatic plant that belongs to the Pistia genus in the arum family. Water lettuce’s scientific name is Pistia stratiotes, and it was first found in Africa and South America.
Now, you can also find it in the Southern United States and other European countries. The plant has an exquisite look with its small rosettes of thick and soft green leaves with hidden flowers and long feathery roots.
Benefits of Water Lettuce
Fights Against Algae
Algae grow intensively and ruin both ponds and aquariums by turning their water green, decreasing the oxygen levels, and killing fish. Water lettuce can help as they provide shade for the water, and so it deprives algae of the sunlight that makes them thrive.
A natural filter
Water lettuce will help clean your aquarium. It consumes uneaten fish food and waste such as Ammonia, Nitrites, and Nitrates, and so, it helps with the Nitrogen cycle, which we’ll talk about furthermore. That doesn’t mean that you should sit back and not change the tank’s water (Sorry!).
Shrimp and Fry Love Them
Fry (baby fish) and shrimps love to hide in the shade of this plant. That’s why you will find them hiding in the plant’s long roots. It also provides a shelter for small or shy fish to reproduce and a surface for baby shrimps to go and look for food.
Cons of Water Lettuce
The biggest issue with water lettuce is that it propagates so rapidly that it would crowd the other plants for space until they take over the whole pond or tank. When this happens, the thick mat of water lettuce will block sunlight and oxygen exchange at the water surface.
Could be Illegal
If kept to their devices, water lettuce could grow too much and create a green mat that blocks waterways and transportation and chokes other plants. This is why it’s illegal to grow or transport water lettuce in some countries and cities.
For example, water lettuce is illegal in the following US states: Texas, Florida, Mississippi, Louisiana, California, South Carolina, Alabama, California and Florida. It’s also banned in the United Kingdom and New Zealand.
Not Good in Winter
Because it’s a tropical plant, keeping water lettuce alive through the winter could be challenging. It’ll need extra care to overwinter it, but you might choose to throw it away and get a new one in spring (they’re inexpensive). Though, never dispose of the plant in water bodies because it’ll multiply fast until it ruins the water.
Caring for Water Lettuce in Aquarium
The best type of tank for the plant is tropical and subtropical freshwater tanks. Since the plant propagates fast and its roots float in the tank (floating plant), the smallest tank size you’ll need for the dwarf plant is 10 gallons.
If you’re keeping the tank in a dry room, cover the tank with a lid to keep the humidity necessary for the water lettuce. If you’re keeping the plant in an aquarium, make sure the top has enough holes for the oxygen to get in so your fish won’t die, or insert an air pump device.
Make sure the water temperature range is 72-86°F (22-27°C). As for the pH range, it should be from 6.5 to 7.5. You should also keep the water hardness to (3-8 GH), and if it got more than 12 GH, the water lettuce’s growth would zig-zag.
Even though we give you ranges of water conditions, there isn’t a perfect number to hit (and most tanks bred fish adapt to whatever pH the water is born in and have lived in captivity). The key to aquarium life is stable conditions. so aim for stable conditions among the suggested ranges.
Remember that swinging water conditions are one of the biggest killers of fish communities. You can see some extra info here.
Just as water lettuce provides shade for your small aquarium pets, they need shade. If you’re growing the plant indoors, you can either use sunlight and put the tank near a window or use fluorescent grow light (T5 or T8 full-spectrum small bulbs).
However, if you’re growing the plant outside, you can provide shade by growing taller aquatic plants (such as Water Lilies) over it.
Water lettuce needs at least 11-12 hrs of light to flourish but make sure to introduce the light gradually when you buy it to avoid burned leaves.
Because water lettuce grows originally in the wild, they’re pretty much self-sufficient, and it has almost no disease or pest issues. Nevertheless, you will have to monitor its growth weekly. If you found it starting to take over the water surface, interfere fast by trimming and uprooting the plants (again, do not throw in water bodies)
Upon buying the plant, cut any brownish or yellowish leaves and quarantine the dwarf plant for two weeks before putting it into an aquarium.
Water lettuce propagates both sexually and asexually, but in aquariums, it mainly propagates asexually, and you’ll find the small daughter plants it reproduces attached to the mother plant with a stolon. Don’t worry if their growth starts slow because it’ll increase in a few weeks.
How to Use Water Lettuce in Aquarium
In Aquariums, you could use water lettuce to help the nitrogen cycle as it consumes decomposition elements. The Nitrogen cycle ensures the aquarium’s ecosystem is safe for fish to live. It’s common for beginners to miss this (known as new tank syndrome).
If you want to grow water lettuce in your aquarium, keep these factors in mind:
- It’s preferable not to put another aquatic plant with them. By now, you know that they like their space and who can blame them?
- If your filter causes strong currents in the tank, the long floating leaves and feathery roots of water lettuce could clog the machinery. As a solution, block the plant (i.e. with rocks) or cycle it tie it with a fishing line so it won’t float away.
How to Choose Healthy Water Lettuce
To ensure that the water lettuce you’re getting is healthy, don’t buy them during extreme weather. In the winter, avoid purchasing the plant on days of low temperature (below 20°F). While in summer, avoid days with high temperatures (above 100°F).
If the plant is shipped to you, the roots may look squished or trimmed, and they may fall off during the delivery. But don’t worry, and just put them in the pond or the tank for a couple of weeks, and the roots will rebuild themselves.
Is Water Lettuce Right For You?
Despite its reputation, water lettuce can do good to your pond and aquarium not only because of its pretty green leaves but because it will be home to the baby fish and shrimps you have and will help clean the water and repel algae.
You’ll only need to monitor them weekly to check if they need extra help. After all, what living being doesn’t need extra help?