Hints of autumn appear to be everywhere. The kids are back to school and routines; in some places, leaves are changing (already!); pumpkins and apples are appearing in local grocery and produce store and produce stores and heavier blankets are being pulled out of closets. Well, you get the picture. There is a definite nip to the air and fall is just around the corner. It is time to get the water gardens and ponds ready for fall and winter and the fish ready for their long winters nap. Rotting plants, dead bugs and bacteria can accumulate, so now that the air is cooler, you can take the time to clean all that nasty gunk out.
You may also notice that your water plants, such as water lilies are slowing their growth and getting ready for dormancy. Do not feed or fertilize any of your outdoor garden plants from now on. Now is the time to trim the dead and fading foliage, but you can wait until the first frost for that (some time after the middle of October). You can take this opportunity to bring in your tropical marginal plants indoors since the nights are getting colder. In order to protect the hardier of your pond plants, lower them to the bottom of the pond for the winter. You might want to wait until spring to divide and transplant the rest of the marginal plants for your pond or garden.
If you are leaving the water in, you will want to take this opportunity to put some sort of protective netting or screening over top of your pond because of falling leaves. This will stop them from entering your pond. But make sure the netting does not enter the water as the fish can get caught in it. Put a piece of dowel in the middle of your pond or water garden and put the netting over it, in much the same way you would do a tent. If you want to empty out your pond of water, now is the time to do so. As the water empties, you need to get a stiff brush and wash down the sides of the pond and clean the rocks and the bottom of the pond. Clean up the debris on the bottom and refill the pond half way (do not forget to dechlorinate the water!). Before emptying your pond, however, you need to decide what you want to do with your fish. If you live in an area with a harsh winter climate, you might want to bring them indoors and put them into a holding tank for the winter months.
However, some fish can stay out doors all winter. My father in law simply cleans out his garden pond, refills it and leaves the fish in all winter (making sure that the top never gets frozen over, so the fish can breathe). You too can do this by feeding your fish a higher carbohydrate diet (and lower in protein) when the autumn begins. During the winter, fish do not hibernate, but their metabolism slows way down as the water cools. If you fatten the fish up before winter, they will not need to be fed during the winter because they will have enough to live on during the winter. Do not feed your fish during the winter since their metabolism has slowed down that they will not be able to properly digest the food even though they may seem hungry! Some people place wood over the top of the pond to keep predators away from the fish over the winter months and this will help deter the growth of algae during the sunny days of winter and into the early spring. Your fish will survive in water that is as little as eighteen inches as long as the water does not freeze solid.
While you are maintaining your water garden or pond, you will need to take a look at your filter. This is the time to clean it thoroughly and store it for next spring. Do not store them where they will freeze such as a shed. Place your de-icers and bubblers into the pond or water garden and keep a careful eye on it during the winter so it will not freeze over. NEVER break the ice if it has frozen over because it sends shock waves into your pond or water garden and can scare or kill your fish.
That is about all you need to worry about. The hard and sometimes nasty work will be done in the autumn and your water garden or outdoor pond will be ready and waiting for the warm months of spring and available for you to enjoy again next year.