How To Overwinter Floating Pond Plants

Over wintering allows pond owners to introduce floating plants as soon as weather permits.

Over-wintering your floating plants is easy and extremely rewarding. You will be relishing the majesty of large, blooming plants early in the season while others are wishing their small starter plants would hurry up and grow. Pink water lilies. Via LASZLO ILYES/Flickr

All summer long you have enjoyed the tranquility of a magnificent water garden or pond. But, as summer ends in the colder regions, it is time to prepare your water feature for the changing season. Labor Day is normally considered the end of pond season and is a time when pond and water garden owners begin the slow process of preparing their ponds for the winter. Many owners labor over the decision on whether to over-winter their fish in the pond or move the fish indoors to an aquarium.


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Regardless of how you over-winter the fish, all water plants must be removed. Floating plants normally die with the first frost and begin decomposing. The decomposing vegetation will settle to the bottom creating filter clogging muck that must be removed prior to restarting the pond in the spring. Dangerous conditions are also created with the winter’s decreased oxygen and the degraded water quality that will exist with over-wintering fish.


Over wintering allows pond owners to introduce floating plants as soon as weather permits. Photo by Stephen G. Noble.

At season’s end, many pond and water garden keepers simply toss their floating plants into a compost pile. However, I over-winter my water garden plants for the following reasons:

  • My water garden is in a fairly warm and protected location which often allows me to begin springtime operation six weeks before any local pond shop sells water plants.
  • It does not make sense to throw away perfectly healthy plants.
  • Newly acquired plants in the spring are typically small and bring premium prices.

Through research, I found a few suggested methods for over wintering floating plants posted on various websites. Be cautious, though, because what I discovered was mostly conjecture. It took several winters of testing and trials to figure out the best way to overwinter water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes) which are two very popular floating water plants.

Here is the formula for maintaining a couple of water hyacinth: Position a 10 gallon aquarium in a south or west facing window in a warm room. Spread a three inch layer of rich garden soil along the bottom of the tank. Add enough pond water to make a total water depth of about six inches. Select a couple of healthy, medium size, water hyacinth for indoor overwintering. Do not trim or allow the roots to dry. Gently secure the roots in the dirt substrate. Do not fertilize. Within a week, the plants should show a little growth. Watch the plants for stress or signs of failure. For example, yellow leaves, shrinkage etc. In this case, add artificial lighting especially during December and January when the Sun’s photoperiod is short.

Here is the formula if you want to propagate water hyacinth over the winter: Set up the tank with the amount of garden soil and pond water as mentioned above. Use a bright light, for example a T-5 strip plant light positioned on the top of the tank, making it very close to the plants. Add a capful of aquarium liquid fertilizer weekly. The plants might initially grow a substantial root system with very slow leaf formation but will soon develop long stems and large leaves. In the event you become inundated with new runners, shorten the artificial photoperiod and reduce the nutrients to prevent crowding. A good growing tip is to mist your water hyacinth twice a day. They enjoy humidity.


This set up is about one month old. Look for new growth. Yellow or shrinking plants is a signal of trouble. Photo by Stephen G. Noble.

Here is the formula for water lettuce success: It grows well in brightly illuminated aquariums as long as it is directly under the light. The plant will not grow in a dimly lit corner. I have been successful growing it under T-5 and LED plant lighting. The challenge is keeping a floating plant directly under the light due to being pushed around by the water’s current. One way to keep them directly under the light is to use a Styrofoam ring wedged between the water’s surface and the tank’s glass cover. The water lettuce will grow if it is contained in the ring. Aesthetically, it is ugly but it works. Another method is to contain the water lettuce in a dense growth of Salvinia which forms a thick mat on the water’s surface.

Over-wintering your floating plants is easy and extremely rewarding. You will be relishing the majesty of large, blooming plants early in the season while others are wishing their small starter plants would hurry up and grow.  Enjoy your pond!

Article Categories:
Fish · Ponds and Koi