When the days shorten and there's a chill in the air, your main concern will be dead foliage falling into the water, whether from pond plants or nearby trees, shrubs and hedges.
It is very important to prevent this from happening, as the decaying leaves will release gases that are harmful to both fish and plants, and may encourage algae growth in the spring.
Remove Dead Plants
So remove any dead foliage from the water, and also trim back summer growth and generally tidy any pond plants, dividing any that are becoming too invasive. Some plants around the pond may also not be fully hardy, so think about protecting them with fleece.
Remove any debris that the pond has collected over the summer with a net or pond vacuum before protecting it from autumn leaves with pond netting
There’s a wide range of pond netting available and you can choose between clear, black and green. This can be bought off the roll or in set sizes of up to 72 sq mtrs. Heavy duty netting will last for several years and child safety pond netting, although never replacing adult supervision, is also obtainable and can be used with many other water features.
Also don’t forget that netting provides another valuable service, that of keeping predators away from your fish.
Pond thermometers are useful to judge the amount and type of fish food that is required. As the temperature falls, fish do not require as much food and anything that is undigested will contaminate the water, so use lower protein feed before stopping completely.
Filters and pumps can be removed, cleaned and stored away once the temperature goes below 10C, biological activity in the pond will have ceased and pumps might disturb overwintering fish and frogs which retreat to the bottom of the pond in cold weather.
Measure the water quality with an easy to use test kit. Nitrates may have built up over the summer and these are harmful to fish. You should also discover the water’s pH to ensure exactly the right environment for pond life to flourish in readiness for next year.
Ice is another eventually best avoided. It will put pressure on concrete ponds and may lead to cracking. Although over wintering fish and amphibians will survive under ice for a certain amount of time, ice traps gases escaping from decaying material and prevents oxygen from entering the water. Snow cover also cuts off light, preventing plants from producing oxygen.
Use a pond heater or aerator to ensure an area of your pond stays ice free. Heaters, some thermostatically controlled, are efficient and economical to run while air pumps, suitable for many different pond sizes and depths, will keep both the water ice free in winter and reduce carbon dioxide levels in the summer ensuring an oxygen rich pond.