Special fall pond care is necessary when our plants and fish begin going dormant in cooler weather. When temperatures start dropping and we know that Indian Summer is just around the corner, our pond requires that we slow down or stop many things we did daily or weekly in the hot summer.
Our water lilies pads are getting smaller and they are blooming less and less. Water lilies respond to temperatures and length of daylight. Stop feeding your lilies in the fall and allow them to go into dormancy. If you stimulate growth now, you could lose the lily when winter freezes hit your part of the country. Lower them to the bottom of the pond if they are not there already. They will over winter better there where the water is warmer. If they are hardy lilies, they will be fine in freezes. If they are tropical special care is needed to keep them through the winter.
If your bog plants are tropical you can bring them in the house and hope they will survive. Many of them, like taro, callas and cyperus do not require being in water and will do well in soil or sand. Bring them in the house, keep them in medium light and they should do fine. If your plants are hardy, just cut them back to make sure none of the emergent vegetation freezes, dies and fouls the pond. The hardy bog plants will come back in the spring bigger and better.
Remove Japanese Iris and Lobelia cardinalis and plant it in the ground if it freezes where you live. Mulch it up good and they should survive nicely and be ready to put back in the pond in the spring. Remove canna rhizomes from their pots. Store them in a pot in peat in a basement. Keep the peat damp.
If your pond is below the freeze line in your part of the country, your submerged plants should do just fine. If not and your pond freezes solid, bring them in the house right before the freeze and keep them in an aquarium with aquarium lighting.
If you feed your fish, when the temperatures start to drop below 60 degrees F, ease up on the feeding. Feed no more than two or three times weekly. Fish are cold blooded animals whose body temperatures are the same as ambient temperatures, therefore their metabolisms are slowing down as temperatures drop. When metabolisms slow, digestion slows as well. If you feed the fish too much, they cannot digest it and may die. When the temperatures drop to 50 degrees F, stop feeding completely.
Your floating plants are getting smaller and smaller, so cruising herons and egrets can see your fish more easily. To protect your fish make places for them to hide. You can buy "castles" commercially or you can turn some clay ponds on their sides. Another good hiding place is a large flat rock placed on top of a couple of chunky rocks makes a great spot for fish to get away from hungry birds.
Leaf netting will keep the predators away as well as keep debris out of the pond.
It's time to get all the falling leaves, debris, sticks, dead and decomposing organic material and fish poop off the bottom, in the waterfall cracks and sides. You can do a total cleanout, use a pond vac or a siphon if you can. No matter how you do it, the pond has to be clean and it sure is easier to do it now than the night before a hard freeze.
If you have a skimmer, it will not remove the leaves. It is made to remove the occasional leaf, not a tree full. You can cover your pond with leaf netting. You can buy it at most nurseries or make it from nylon net available in most big box stores.
I have known some folks to pound stakes around their ponds and cover the entire pond with visqueen, making a pond greenhouse. This will add at least 10 degrees to the temperature inside your greenhouse. Putting lights under there will add even more heat and keep leaves and other debris out of the water. Just make sure air can get in and out.