Water features are long-lasting garden enhancements that can provide many years of enjoyment with proper care. Some basic steps will ensure that your feature will weather the winter in good shape to enjoy again next season.
If you have a small feature like a fountain or birdbath with no plants of fish, simply draining, cleaning and covering it, and storing any pumps submerged in water in a frost free place may be the extent of your winterizing. If it’s small enough to move, storing it indoors for winter is easiest. Pottery or cement fountains and recirculating water features too large to move should be covered to prevent rain or snow from accumulating and freezing inside as this can cause breakage.
Water features that hold plants or fish need a little more attention. Just like in the garden, keep water plants cleaned of yellow leaves as they occur. Stop fertilizing the pond plants as weather cools and stop feeding fish when water temperatures reach 55F to keep them from getting sick—or even dying.
If you have any tropicals in your pond that you’re hoping to save for next year, remove them when the overnight temperatures are consistently in the low 50s and overwinter them, pots set in a watertight bucket, in a cool, dark area for the winter. Keep a few inches of water in the bucket through the winter. In spring, when night temperatures are at least 50 degrees, move the whole bucket outside, remove any dead leaves, and add fresh water. When you observe new growth they can be returned to the water feature. Tropical floaters can be kept in an aquarium in a bright window over the winter. Only a small piece needs to be kept alive, as most floaters reproduce rapidly.
After a few frosts turn the leaves and stems of perennial water plants brown, cut them back. You want to keep as much vegetation out of the water as possible, so skim out as many fallen leaves as possible and check and clean the filter regularly. You may even consider covering with mesh netting to catch falling leaves. Add a fall/winter microbe additive to accelerate breakdown of remaining leaves even through the colder winter months.
Decide if you will remove your pump or not. If you have no fish you can remove the pump and let your water feature freeze over. If you remove it and you have fish, you will need a bubbler to keep a hole open for proper oxygenation of the water when it’s cold enough for ice to form. This should keep an ice-free hole during all but the coldest weather, for which you’ll need a floating de-icer. Store the removed pump in a bucket of water and keep from freezing.
If you decide to keep your water feature’s pump running for the winter, monitor water levels to keep the pump from running dry and possibly freezing. Freezing will damage a pump by cracking the housing and perhaps even opening up the sealed electrical components to water.