Looking after your pond
Once you’ve built your pond, big or small, there are lots of things you can do to make sure it remains a happy home for the wildlife which lives there.
Weeds and plants
When your pond is established, you should find that, to an extent, the plantlife is naturally maintained by the pond animals which live in it.
Various creatures will keep the level of algae and blanket weed down by eating it for example. But with new ponds, which are yet to host the wildlife which can help keep things clear, you may find blanket weed quickly covers the water’s surface, especially in warm weather.
Either way, if you get a build up of floating weeds like this, you can carefully remove it with a stick or net. It’s best to leave the leave the weeds and algae by the side of your pond for a night or two, so that you can give any remaining creatures living in it the chance to escape back to the water!
Sometimes other plants can also threaten to take over. Lots of emergent plants for example, can be very invasive, but are also be a brilliant habitat for lots of wildlife. They’re easily managed if thinned out regularly, however it’s best not to clear more than a third in any one year and, as with floating weeds, it’s a good idea to leave plants by the side of the pond to allow the little beasties which live there to escape to the remaining foliage.
Algae, or algal blooms, can sometimes take over a pond.
They’re naturally occurring aquatic plants and most are not harmful. Those that are though, often only become so because of certain environmental conditions.
- Increased nutrient levels in the water, which in a domestic situation is often a result of high numbers of fish
- Long periods of calm hot weather
- Low water levels
- Lack of adequate water circulation
Using rainwater as opposed to water from a mains tap can often help reduce the amount of nutrients for the algae, as can the addition lots of oxygenating plants, which will soak up the minerals the algae would usually feed on.
During hot calm days where the water’s still and warm from the sun, you can try breaking the surface with a brief spray of a hose, to disturb and aerate the water a little. Introducing plants like waterlillies, which have floating leaves, can also help, by reducing the amount of sunlight the algae can get.
Using straw as a preventative
Generally speaking, an established well balanced and maintained pond shouldn’t have too many problems, but if algae levels do get out of hand, you could try a preventative method like barley-straw.
A chemical reaction between the straw and algae slows down the growth of new algae, and as a result, unable to replenish itself, it slowly dies naturally. How quickly this happens and how well it works varies, but you may find that it happens quicker in higher temperatures.
The straw should be packed, firmly but not too tight, into netted bags. You might need to include something like an empty plastic bottle to help it float on the surface, and you should anchor the bag in the pond, so that it can naturally float around in the breeze and cover as much as the pond as possible.
The minimum amount of straw you’ll need is about 10 g per square metre of water surface area. In particularly bad cases, you could use higher doses, 25 g for example, and reduce the amount over time.
Sometimes, especially during the summer, you may feel the need to top up the water in a pond.
In dry weather the water level can often drop down a little, but it’s nothing to be too concerned about. Most plants and certain types of insect can cope with this quite happily, some even benefit from it.
If you do become concerned that levels are getting too low, then you can re-fill it slightly. However, if possible you should use rainwater from a water barrel - avoid getting it from a mains tap.
If the water loss seems to be a continuing persistent issue, it could be that your pond has a leak. In this scenario, you could try and carefully drain your pond to inspect the lining for damage. This should be a last resort, and ideally done at a time that is least disruptive to any wildlife, between late September and October for example, when tadpoles have gained legs and left the pond and adult frogs are yet to hibernate.
Any foliage, silt and potential wildlife habitats, should be carefully preserved and re-introduced when the leak is fixed and the pond refilled.
Autumn and winter
In the autumn ponds can often become covered with fallen leaves and decaying plant matter.
This time of year is a good time to remove this kind of thing from your pond, as well as cutting back any invasive plants that have spread themselves out over the summer.
In winter, although it’s rarely cold enough for a pond to completely freeze, a pond’s surface can sometimes freeze over. You can try floating a ball on the surface of the water to delay any ice forming.
If it’s already frozen over, it shouldn’t be too much of a problem, unless you have fish in your pond. Many plants will continue to grow and produce oxygen beneath the surface, as long as they have a good source of light. Any snow that collects on the ice can be brushed away to make sure the sun gets through.
Birds might appreciate a small hole in the ice though, so that they can drink and breaks around the edge of the pond may help amphibians who need to come up to breath should there not be quite enough oxygen below the surface.