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 North Central USA

A checklist of essential pond projects . . .

 When Autumn Leaves
Start to Fall

by Joe Summers, St. Louis, Missouri
Images by Louis Belloisy - Click to enlarge

Autumn ushers in a colorful change in the landscape. This means change in your water garden. Analyze your fall maintenance this year and perhaps you can become more effective in this most important pond undertaking.

Before tree leaves begin falling, give attention to four pond-care categories - netting, plants, fish, and filters. Each category relates to the other. Divide them up to tackle one at a time, to make your task of pond winter-preparation easier.

Netting. Netting over the water is a vital pond-maintenance concept, and netting the pond is the most essential project for winter preparation. It seems that a water garden attracts leaves as a magnet attracts thumbtacks. Even if no trees grow in your yard, leaves from area trees tend to end up in your pond. Keeping them out of the water does matter.

Discolored water signals the first noticeable change when excess leaves gather in the pond. Your once-beautiful, healthy pond can quickly become a pool of tea-colored water. If you allow too many leaves into the pond, the water may turn gray. This means that decomposing leaves are making the dissolved oxygen level too low. At this point, fish cannot survive unless you do something quickly. 

Rate installing a net over your pond as the most important project to accomplish in the fall. This prevents the leaves from entering the water and fouling it. Inexpensive nets made of plastic last a few years; nylon nets last a lifetime. The key when netting the pond is to prevent the net from resting on the water surface. Install netting like a dome or tent over the pond. When you accomplish this properly, tree leaves do not enter the water.

If you overlook netting your pond before leaves drop, then daily remove as many leaves as possible with a scoop net. This cold and dirty job may remind you next season to install the netting before trees shed their foliage.

Plants. Water plants, just like non-aquatic plants, are either hardy (can survive outdoors all winter) or not hardy (cannot survive outdoors all winter). Hardy aquatic plants are easy to care for during fall and winter because all you need to do is remove the foliage after a heavy frost and then make sure that their roots rest safely below the ice. Cut and remove all the plant material - leaves, stems, flowers -- to avoid problems down the road if too much decaying plant material remains in the water. If you chose not to bring tropical plants indoors, and then take them out of the pond after heavy frost so the dead matter (great for composting) does not foul the water.

Fish. Ah, the fish may cause you to worry, but you should not. Fish that usually inhabit water gardens are hardy. Therefore, the goldfish, golden orfe, and (in milder winter climates), mosquito fish and your prized koi may over winter outside quite happily. They should be just fine as long as your pond measures at least 18 inches (46 centimeters) deep.  

Check your pond thermometer. When your water temperature falls below 65 F. (18 C.) degrees, feed your finned friends a food specifically made for cool weather. Fish more easily digest the special low-temperature food containing less protein and more fat. Easy digestion matters because fish have a reduced metabolism when the water cools. In fall, they store extra fat to consume slowly over the long winter fast.


Filters. Just like changing fish food because of cooler water, change how you treat your filter(s) as water temperatures tumble. A filter is a living, breathing part of your pond. Countless beneficial bacteria reside and work in the filter. During summer months, warm-water bacteria inhabit the filter. However, during autumn as the pond water cools, add bacteria that thrive in cooler water. Suppliers usually blend into their bacteria products specific cold-tolerant bacteria that consume both plant waste missed during the plant-trimming activity and the leaves that fall into the water.

Take time to prepare your pond for winter. Your fish will thank you. Moreover, you will have more time to enjoy autumn's colorful shades and winter's stark beauty.

Learn how to survive the impeding ice in the next issue. 

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