The key to keeping a water garden’s ecosystem in good shape is to limit the amount of organic debris in the water. Keeping leaves out of the pond can be a challenge when autumn leaves start to fall.
Why is limiting organic debris in a water garden so important? During winter months, organic debris will rot and release harmful gases. (In natural earthen lined ponds, these gases can be released through the soil at the water surface, but lined ponds hold all the toxins under the ice, and can cause fish and frog fatalities).
1) Cut Back the Plants
I have tall marginal plants in the pond, so in order to put the netting over the pond, I have to cut the marginals back so only a few inches of stems are left sticking out of the pots. I feel ruthless doing this, but if I don’t cut them back now, the foliage dies back and ends up in the water. Then I have to remove slimy plant stalks when the water is really cold, or have a rotted mess to clean out of pots in the spring when the plants leaf out. I even trim back the lily leaves and stems to limit what will decay in the water over the winter.
If the pond water is already cold and you have to keep your hands in the water for any length of time, try Atlas Water garden gloves. These gloves are a little bulky – they come up your whole arm to your bicep! – but they make reaching into cold water tolerable. I put off getting pond gloves for years because I didn’t think they could make a difference. Then, a few years ago, it got cold fast and I had to reach down into deep, freezing cold water that felt like thousands of needles. In desperation to complete my tasks, I bought a pair of these Atlas water garden gloves and now I use them every fall and in the early spring too.
2) Net the Pond
I’ve found that it is best to put netting over the pond just when the leaves in your neighborhood start to drop. Even if you don’t have trees near your pond, or in your yard, the wind will blow them into the pond and they will sink to the bottom. I use Dalen pond netting because it’s economical and the holes of the netting are small. (If the holes in the netting are too big, the leaves fall right through the netting).
I also like using DeWitt’s Deluxe Bird Barricade Netting to cover ponds. It has a tight mesh too but is a higher quality netting, so it isn’t as stiff and wiry. This Dewitt netting has a knitted look to it, moves more like fabric, and can be reused for quite a few seasons, but is much more noticeable covering the pond.
If you already have leaves in the bottom of the pond, get a net, scoop out all the leaves you can, and put netting on. Trust me, even if most of the leaves already dropped off the trees, there will be more leaves that will continue to blow in and accumulate in the bottom of your pond.
3) Put the Fish on a Diet
Koi and goldfish can only digest a limited amount of protein when the water temperature is below 70° F. The remaining protein they are unable to digest is excreted as toxic amonia, decreasing water quality. To reduce pollution and amonia produced by fish waste as the temperature cools, you should have already switched to a fish food specially formulated for spring and autumn conditions based on your water temperature. I feed Pond Care Spring & Autumn Premium Pellets when the water temperature is cooler.
At 55°F, the fish’s metabolism starts to slow, reducing it’s food requirements. In fact, you can see the fish move slower in cold water. Do not feed fish if there is a chance of the water temperature dropping below 50°F within a few day period. Fish are not capable of proper digestion in cold water and food can actually decay in their system and even kill the fish! In most zones of the USA, this means you will not have to (and should not) feed your fish all winter.
4) Turn off the Pump
While leaving the pond pump run throughout the winter can create beautiful ice formations on the falls, letting the pump run all winter involves more work. Ice dams can form in streams and waterfalls, which can divert the water out of the pond. If you leave the pump run all winter, you will have to regularly check the water level of the pond. Water still evaporates in the winter -the water level can drop under the ice so you don’t notice it. Also, the pump can still get clogged with debris in the winter, so it needs to be checked regularly too.
In my opinion, it’s just easier to turn off the pump. Connecting a hose to the outdoor faucet to top off the pond on a cold winter day is not for me, so I unplug my waterfall pump each fall, clean it off, let it dry out, and store it in a dry place. We also hose out our external waterfall filter box (and drain it) so it’s ready for spring.