Planning a Garden Pond Feature

They attract wildlife many people never see, especially city dwellers. But such a large undertaking needs careful planning or you will end up wasting a large part of your garden. When planning a water garden you must decide what wildlife you want to attract before you dig your pond because its position, size and shape will affect its appeal to different species. First, you have to be sure what you want from your pond. A relatively small garden or school pond is a great idea for interest and pleasure, as a place where birds can drink, children can be shown wildlife, or a more ornamental pond for fish. In general, for wildlife, the larger the pond the better, provided there is a wide variety of habitat.

Think about where to site your pond, warm, sunny sites are probably best for wildlife, so try to make sure your pond has an open aspect to the south side. Trees can be a problem: if your pond is sited under mature trees, it may fill with autumn leaves, but if it is under young trees you may have problems with roots puncturing the pond lining. Low bushes near a pond can provide cover for bathing birds, but remember that they can also harbour cats. For better bird watching, build your garden pond so that you can see it from a window. Do not automatically place your pond in a wet or damp hollow. These areas may already be important for wildlife.

A ponds shape is important, gently sloping sides give a pond the all important shallow areas on which much wildlife depends. Birds will drink and bathe in the shallows, and they are important for spawning amphibians. Slopping sides are also important for safety, both for children and to allow wildlife such as hedgehogs to escape. In general, the more varied the slopes and the longer the shoreline, the better.
Although the shallow areas are important for insects and spawning frogs, ponds should also have some water over 60cm deep, so that they do not freeze solid in hard winters.

When constructing your pond you will need a pond liner and most pond lining material is made from either polythene or butyl rubber, but some ponds are clay or concrete-lined. You can buy pre-formed plastic liners from garden centres, but, for wildlife, many of these are more trouble than they are worth: they are difficult to fit and level and tend to be very steep-sided. They are also very expensive for their size. After digging the basic hole for your pond, line it with a smooth layer of newspapers, sand or old carpet to prevent the plastic liner being punctured. Lay the liner in the hole, but do not stretch it too tight. You must allow room for it to expand. Make sure the liner is large enough to overlap the edges, and weigh it down. These edges can be covered by turf to give a pleasing appearance and to protect them from sunlight. Add a further layer of sand or soil over the liner once you have laid it to prevent it being broken down by sunlight. Fill your pond with water, and allow it to stand for a couple of days before stocking it to allow any chlorine in the water to dissipate.

Maintaining the water quality

The balanced planting of a pool should produce good water quality, but such quality from the point of view of the plants and fish is not necessarily the same as clarity. Indeed, water with a slight green algal bloom or a warm amber colour is probably as pleasant an environment for the fish and snails as the harsh crystal clear clarity sometimes achieved by filtration. The importance of acidity and alkalinity with regard to a garden pool can be over-stressed. Acidity and alkalinity only cause difficulties when they are extreme, and usually there is evidence of problems with the growth of plants and development of fish which would make even the most inexperienced water gardener to consider testing the water. If you read the catalogue of an aquatics specialist or visit the water garden department of a garden centre, you could be forgiven for thinking that the control of water quality was the most important element in water garden management. There are cures and antidotes for every water condition and products that also improve the quality of the water. All are perfectly legitimate and practical, but only when there is a problem, which if the pool is planted and stocked responsibly is likely to be very rarely. The need for many of these medications is only likely to come up when there is an over-population of fish, or if Koi Carp is kept in large numbers without plants. Chlorine is probably the chemical that will present the most concern, although it rarely produces serious consequences in a garden pool. It is true that a pool which has been recently filled with tap water may be laden with chlorine, but during the warm summer weather it evaporates quite quickly. If you are still concerned about its presence, then there are products which will neutralise it. The main problem with chlorine is the irritation which it causes fish, in severe cases causing extreme discomfort and reddening around the gills. The balance of plant growth, which should ensure water clarity, together with the responsible introduction of fish, normally ensures that still water is of acceptable quality. How stable this balance is depends upon the size of the pool. In a large pool it is much easier to keep a stable balance than it is in a small body of water, despite the fact that both are effectively closed eco-systems.