Winterizing Your Pond

Winterizing Hardy Aquatic Plants


By the end of September you should have stopped fertilizing all plants.  Marginal aquatics should be cleaned up as soon as frost has turned foliage brown. Before you trim the plants, lower the pots so that the crowns of the plants are below ice level. Then trim to just above the water level, usually about two-thirds of their height. Many marginal’s have hollow stems and will die from being completely submerged. However, umbrella palms and rush-like grasses look good dried in the pond over the winter. If the fronds break and drop into the water, be sure to remove them.


Remove excess hornwort and anacharis and repot healthy ends into gravel pots. Most years, hornwort and anacharis will successfully over-winter although these plants will sometimes break up as winter approaches and over-wintering buds or pieces will fall to the bottom to regenerate in the spring.

Hardy Water Lilies

Hardy water lilies do not need winter preparation and will die down naturally. Keep leaves that have turned yellow trimmed. Do not allow the debris from the trimmings of your plants to remain in the pond. If it looks like the ice will reach the pots, then lower the pots deeper in the pond.

Winterizing Tropical Plants

Tropical and tender aquatic plants should be kept in a greenhouse pool all winter, but lacking that  facility, some plants such as dwarf papyrus and umbrella plants may be kept as house plants if their roots are kept moist. You can set the pots inside a decorative, watertight container filled with water. Set them near a sunny window, as they need lots of light. Plants like elephant ears and variegated cannas may be stored in the garage, out of water, as long as they do not freeze. Water lightly once a month to prevent plants from completely drying out.

Tropical water lilies are not hardy in this area. They can be kept inside a greenhouse pond in a full light situation. If a pond is not available, there are three methods of over-wintering tropical lilies:

  • Remove the lily, treat with a fungicide and pack in wet sand and store in a location that doesn’t freeze.
  • Let them die back naturally and then dry the plants by placing on a shelf in an area that doesn’t get cold enough to freeze.
  • The third method is to let them die back and store in distilled water in a cool (60°F) dark place. To rejuvenate, float in water (70°F or above) and pot when the plantlets sprout.

Floating Plants

Remove water hyacinths and water lettuce from the pond after the first frost. Do not allow them to break down and fall to the bottom of the pond

Winterizing Your Pump

It is not necessary to operate a circulating pump or fountain during the winter. However, it is quite pretty running in winter. Just take a few precautions. In order to avoid lowering the water temperature too much (which could be detrimental to your fish), raise your pump so that it is below the ice level but not at the bottom of the pond. If you have a waterfall, put the pump directly under the fall, thereby allowing the smallest amount of water circulation. Never store your pump dry or in the spring you may have a broken pump. If you are not going to keep your pump running, store it at the bottom of the pond or in a bucket of water.

Cleaning Your Pond

Fall is the recommended time for cleaning your pond. To clean, empty your pond by storing all plants, either in buckets or covered in wet newspaper. Keep plants out of the sun and douse them with water to keep them wet. A kiddy swimming pool works great to house both fish and plants.  Catch the fish when the water level is low so as not to stress them. Put them in the kiddy pool or a bucket with water from the pond. Make sure there is a pump in the container to provide oxygen for the fish. Also, test the pH of the water you are removing from the pond and the pH of the new water the fish will be going into once the pond is cleaned. There should be no more that ½ degree difference between the two. If there is, adjust the new waters pH level. After catching fish and removing the last bit of water, scrub pond sides with a brush and water. DO NOT use soap or bleach as this can harm your plants and fish. Rinse and remove any excess water. A wet-dry vacuum works well for water removal. Remember to add a dechlorinator to condition your water and remove the chlorine and chloramines from your water. If you are not going to change your water, remove all debris from bottom and do a 20% water change. Helen Nash, author of The Pond Doctor says if your pond does not have a build-up of sludge or leaves, your pond does not need cleaning out. Just vacuum the bottom and cover with a net to prevent leaves from settling to the bottom. Netting, which is available at our Garden Center, is used to prevent leaves and other debris from accumulating in the pond.

Feeding Schedule of Fish

Feed your fish normally with either Tetra Koi Vibrance until the water temperature drops below 60°F. From 60° to 50°F, feed with Tetra Spring & Fall Diet, preferably in the middle of the day. Many people worry about their fish going hungry in the winter and want to feed the fish on warm days. This is not recommended. Cold weather makes the fish’s digestion slow down and feeding them when temperatures are below 50°F may cause the fish to become constipated. By the time cold weather hits, healthy fish should have enough stored fat to carry them through the winter with no feeding until spring temperatures arrive to stimulate activity. Come March or April, your fish will be hungry again. Do not feed them anything except Tetra Spring & Fall Diet until their metabolism is up and running fully. If your pond containing fish is completely covered by ice for more that a few days, the fish will suffocate because gasses get trapped beneath the ice. This happened more quickly when decaying plant debris lies on the bottom of the pond. The fish only need a small air hole to survive. If the pond freezes, do not pound on the ice to break a hole. This will create shock waves which may injure or kill your fish. It is better to provide a hole before the pond freezes by floating a log on top of the pond or by running your pump.