Preparing your pond for the colder season can be a challenging task! There are several steps to get your koi pond ready for winter – and if it’s too large a project we do offer winter prep! We can also provide direction here at the nursery if you visit during our winter hours: 10 a.m. to 5 p.m. on Friday, Saturday, Sunday and Monday.
How do I cut the plants around my koi pond back in the fall?
Plants start to die back when the water temperature drops, which is why this is one of the most important ways to get your pond ready for winter. Decomposing leaves and other plants can be bad for water quality, so the main goal is to limit the amount of material that falls into the pond.
Cut back plant material around the pond that will have a chance to fall into the water — grasses, florals, etc. If you have deciduous trees above the pond, be sure to regularly use a pond net to capture the leaves as they start to drop.
If you have annual plants like hyacinth or water lettuce, remove these before they start to decompose. You can replace hyacinth and water lettuce in the spring!
When do I stop feeding my koi in the winter?
As the water temperature dips below 60 degrees, we want to switch back to a cool-season/wheat germ food (we sell this at the nursery). Continue feeding fish until the water temperature hits 50-55 degrees (typically mid-October).
As the water temperature cools, fish cannot digest their food as efficiently. High protein Summer food can actually rot in their gut and cause abscesses. As the water temperature drops below 60 degrees you should switch to a cool-season or Spring/Fall food that has more wheat germ which is easier for your fish to digest. When the temperature drops below 50 you should stop feeding your fish entirely until Spring.
What maintenance does my pond equipment need in the fall?
What to keep running:
Pumps: We suggest that you run your pump all year long because moving water almost never freezes and your pond will be healthier if you keep the pump running.
There are two common problems which shorten the life of your pump and void your warranty.
No. 1: Gunk Clogging the Inlets. Look in the back of the skimmer box where the pump is and make sure no pine needs or other gunk has gotten back there. Those of you who do not have a skimmer must be even more diligent in checking your pump. Failure to keep the pump inlets clear voids your warranty and shortens the life of your pump, so make it a habit to check the inlets periodically, especially in the fall when the wind starts to knock all the needles out of your Douglas fir.
No. 2: Weak connections on cords. Never pull your pump up using the cord. Stretching the cord can weaken connections within the pump or cause a leak in the seal around the cord. Either problem will cause the pump to start shorting out your GFI and you’ll need a new pump. Pump manufacturers exclude cord problems from their warranty, so never let anyone pull your pump by the cord!
Skimmer: Once the leaves have all fallen you can clean it less often through the winter. However, as we head in to fall and the leaves and needles start to fall it is important to clean your skimmer more frequently. Remember that you must periodically pull the filter matting out of your skimmer and hose it off very well to clear the needles out of it.
What to clean and disconnect:
UV Sterilizer: We suggest that you turn your UV sterilizer off by unplugging it around October 15th. This is because the water temperature approaches 40 degrees, algae growth becomes less prevalent. If you turn it on in April and turn it off in October, you can use the UV bulbs for two full seasons and replace the bulbs every third year. Keep in mind that if you don’t turn off the UV by unplugging it, then you would want to replace your UV bulbs every season.
If you keep your pump running all winter then you don’t usually have to drain your UV. If you plan on turning the pump off during the winter, then the UV sterilizer valve should be closed and the UV drained to protect it from freezing.
Biological Filter: Clients who have a biological filter (which is not the up-flow filter that many have at the top of their waterfall), can clean and drain it for the winter. Once the water temperature drops to 40°F, the beneficial bacteria in the filter mostly die and stop working. Cleaning and draining the biological filter will prolong the life of the filter media.