There is nothing like a pond to add sparkle and movement to a garden, and it need not occupy a great deal of space — the minimum satisfactory surface area is 3.5sq m (m2). The optimum depth to aim for is 600mm. Even the largest garden-pond need be no more than 750mm deep while 400mm should be considered the minimum depth. Avoid making a saucer-shaped pond — the sides should slope outwards at about 20 degrees to the vertical and round the edge you should form a shelf about 250mm deep and 250mm wide on which marginal water plants can be grown in plastic baskets.
There are basically two modern materials from which to make a pond — flexible plastic and moulded, rigid plastic. Flexible plastic is used for pond-liners which give you complete control over the shape of the pond, while the rigid plastic the size and shape of the pond are controlled by the manufacturer.
These are installed simply by digging a hole
Fountains, lights and waterfalls Low-voltage submersible pumps are available to form fountains or waterfalls. The pump is simply placed in the pond and the low-voltage cable is taken back to the house, through a hole drilled in a window frame, to connect with an indoor transformer which is plugged into the mains supply. Low-voltage lighting sets are connected in a similar way.
The best liners are made from butyl rubber sheeting, which is the material often used to form reservoirs. Second to butyl rubber are nylon-reinforced PVC liners, and there is a third, cheaper sort, which is just laminated PVC.
Planting should take place between late April and early September, and you can begin a few days after the pond has been filled, although you should wait for two to three weeks before introducing fish. Apart from floating plants, all the other types — marginals and oxygenators — are planted in heavy garden soil in plastic planting-crates which are surfaced with a layer of pea gravel. The crates of the shallow marginal plants, such as water irises, are stood on the planting shelf while plants which need deeper water, such as the oxygenators and water lilies, are placed on the pond base.