Ponds, waterfalls and other garden water features are deservedly among the most popular subjects in garden design. Different pond materials all have their advantages and disadvantages, but building a pond from traditional materials – brick cement and clay – was very laborious, and needed considerable skill. In contrast, garden pond liners, which are available from specialist suppliers and aquatic centres, make it easy for a DIY gardener to produce a good watertight pond, and the liner material’s flexibility allow great freedom of design and an attractive natural effect in creating your water garden.
Buying a Pond Liner
- Be prepared to pay a bit extra for a liner with at least a twenty year, or preferably lifetime guarantee. It’s very depressing if your pond suddenly empties a few years after you’ve built it.
- Butyl rubber liners used to be considered the most reliable, but are very expensive, heavy to handle, and not significantly more hardwearing than good PVC pond liners or EPDM liners.
- To decide how big a liner you need, dig the hole for your pond first, then measure the pond’s maximum width, length and depth and calculate:
- Liner width = maximum width + TWICE maximum depth + 2 feet (60cm).
- Liner length = maximum length + TWICE maximum depth + 2ft (60cm).
Design
- Make your pond as big as you can – a large water volume creates more stable conditions for fish and pond plants.
- Slope pond walls slightly to minimise the chance of ice damage.
- Include several different depths with one area at least 18inches (45cm) deep if you’re making a fish pond.
- Ideally, increase the depth in a series of flat shelves where you can stand plant containers, to give:
- A shallow area at the edge about 6-9 inches 15-20cm) deep for marginal plants, where fry and small fish can hide.
- A second shelf about 18-20 inches (40-45cm) deep for plants preferring deeper water.
- A deep area 30 – 36 inches (75 – 90cm) deep. This will stay cool in summer and ice free in winter – a place where fish can hide and planting conditions for deep water plants like many water lilies.
- Always include at least one sloping exit for frogs etc to climb out, and consider leaving part of your pond edge an inch or so lower than the rest, where water can overflow to create a bog garden.
Building the Pond
- When digging a pond try to leave a firm, level edge.
- Remove any stones or sharp objects and line the bottom and sides with at least an inch of soft sand and/or a thick layer of old newspaper. You can buy a special underlay, but sand and paper do just as well.
- Spread the pond liner over the hole, allowing the centre to sag in. Make sure that it overlaps evenly on all sides, and take care not to disturb your protective lining.
- Put a few heavy stones around the edge to stop the liner slipping in.
- Slowly fill the liner with water. The weight of water will mold the liner to the shape of the hole. Don’t worry about folds forming – the water will flatten them out.
- When the pond’s full, disguise the edges with turf, rocks, stone slabs or a pebble beach.
Other Water Features
Flexible pond liner is also ideally suited for creating a whole range of other garden water features, such as waterfalls, streams, bog gardens, etc.
It’s also easy to add the effect of moving water by installing a pump in your water feature.