Winterizing ponds means following a few simple guidelines (and it really isn’t all that difficult). Here’s the checklist based on water temperatures.
Water Temperature Checklist
Those in USDA zone 3 will find water temperatures going down much faster than gardens in USDA zone 7. The timing is going to be much more critical. But here are the recommendations.
When the water temperatures start to drop in the fall (around 70-72F change approximately half of your water. This is an older recommendation that is sometimes ignored by modern pond gardeners.
It doesn’t hurt to do this and it might just help. When the water temperature drops to 60F,bring in the tropical water plants or be prepared to toss them away as they won’t be growing anymore.
In practical terms, the tender tropicals I’m not saving get to stay in their pots until it gets really cold or frosty. These plants don’t grow much anymore but they still look attractive.
When the cold kills them, then I toss them onto the compost pile.
When water temperatures go down to 45F, our winterizing ponds schedule calls for putting the hardy water lilies at the bottom of the deepest part of the pond – assuming your pond is at least 30-inches deep. Before you do this, trim off any leaves and stems. Clean up the plants and then dump them deep. They’ll stay there quite happily until spring and the return of 60F water temperatures.
Once temperatures go below 40F, the fish need attention. If you didn’t stop feeding in September, definitely stop now. If you’re taking them inside – do it now. If you’re leaving them outdoors in deep water ponds, then you don’t have to do anything.
Winterizing Ponds: Check Your Pumps
Temperatures below 40F mean that the pond pumps require attention and any de-icing equipment should be installed. If you’re taking the pump out of the pond, do put it into a bucket of water to keep the seals soft and prevent them from drying out and cracking.
If you live in an area where it doesn’t freeze, then the pond pumps can be left running year round. If you’re keeping fish in the pond over the winter, you may want to investigate either the pond heaters or air bubblers below.
Pond heaters don’t heat the pond water – what they do is prevent a small area of water surface from icing over. This free area continues to exchange gas exchange all winter- keeping fish alive. If you don’t overwinter fish in the pond, then a pond heater isn’t necessary.
There are other options to running a pond heater.
Pond Air Bubblers
Many ponders use large aquarium pond bubblers to keep an area of the pond open in the winter. These work nicely in all areas except during the coldest times in small ponds (but then you shouldn’t be keeping fish in small ponds over the winter anyway)
Pumps to Keep the Ice Clear
Some fish lovers run their pumps year round in cold climates (you do this automatically in warmer areas). But the difference is that the pump is disconnected from the filter and allowed to sit on the bottom with the discharge pointed to the side of the pond.
The circulation of water acts like a bubbler or heater and keeps an area of the surface ice-free. Some fish lovers have warned that doing this makes the pond water colder and reduces fish survival. But generally speaking, as long as the water doesn’t freeze, fish will be fine in my opinion. I suspect more fish are killed from variations in temperature and reduced gas exchange than by colder water.
Fall Clean Out
Part of winterizing ponds involves using a long-handled net/scoop to clean out the dead leaves and gunk from the bottom of the pond. Leaving it there allows it to rot (consuming pond oxygen in the process) and make a mess of the pond.
Allowing debris to remain in the pond reduces the survival rate of fish and frogs (that overwinter in the pond) There are few worse things in the pond world than having a pond that smells like sewer gas in the spring because rotting vegetation has eliminated the oxygen and killed off the frogs and fish. Gross!
If you want to run your pond all winter long and your area freezes solid, here’s a rule of thumb you should consider.
If your pump is moving 2800 gallons/hour you can do this in a USDA zone 4/5. If your pump is smaller or you live in a colder area, your pond will freeze and you won’t like the result. Winter ponds require someone making sure waterfalls don’t ice up so that water flows out of the pond. Ponds also require constant attention to water evaporation and water levels that are too low during winter months.
You can’t run the hose out there so you’ll have to hand-bomb several 5 gallon pails a month to keep the pond topped off. (or more)
A last note, because ice will form in front of the skimmer, most ponders remove the skimmer gate allowing free flow of water into the skimmer and pump. This increases the water flow and reduces the likelihood of ice buildup in front of the skimmer. If ice does build up and stop water flow, your pump will burn out.
I live in an area of winter cold so I have never run my pond during the winter preferring to wintering ponds rather than maintain them all winter. I rather like frozen ponds as part of the natural cycle in the garden.