Building Garden Ponds

Garden and backyards can spring to life with reflections, movement and wildlife, just by adding a small pond.

Britain's gardening guru Charlie Dimmock showed The Early Show viewers how to build their own backyard ponds.

Dimmock said a good pond has a framework that is partially sunken and partially raised. The tools need to build a pond are: a vinyl liner, shovel and spade, a pump, hosing, sand, gravel and wood for a frame.

Flexible pond liners are quick, versatile, easy to install and depending on which sort you use, relatively cheap. Homeowners can make a formal pond with straight edges and vertical sides or a natural looking pond with a curvy, informal shape.

Owners can make stepped planting shelves on which they can stand pots of plants or have gently sloping sides, ideal for birds, hedgehogs and froglets to use to get in and out.

A pond liner can be used to make creative waterfalls or bog gardens. It is also possible to buy a ready-made pond molded from fiberglass. This restricts you in sizes and shapes but does not spare you from digging. Molded ponds are harder to put in than a pond with a flexible liner.

FLOWING POND MADE EASY

Dimmock first suggests that you mark out the shape and dig a hole 9 inches deep. Then make out a central pit and dig to 18 inches. Line the entire shape with 2 inches of damp soft sand, using a plasterer's float to smooth the sand down.

Open the liner and, with someone at each end, lift it over the prepared hole. Lower it gently down and let it relax into the depression.

Get into the pond to help the material fit perfectly into the shape. Take your shoes off to avoid tearing the liner. Ease the material into "pleats" around the planting shelf and even out the creases so they are distributed all around the shape.

Start to fill the pond with water, with the hose running slowly. The weight of the water will help the liner to cling neatly into the shape. Continue to ease out all the wrinkles so they don't end up all in great folds.

Don't trim the edge of the liner until the pond is full of water, as the material always sinks down. Tidy the edges before cutting the liner, leaving about 6-12 inches of overlap all around the sides. Then hide the edge.

TRICKS OF THE TRADE

When making pond lines, you must get the rim level. If one part of the pond ends up lower than the rest, the water will run out at that point, leaving huge expanses of liner showing all around the rest of the pond. Level the site roughly by eye before starting to dig the hole. Use a spade to scrape soil off the bumps and into the hollows. Then check it with a spirit level in both directions - lengthways and crossways. Use a long spirit level and rest it on a straight edge.

Once you are certain the ground is level, you are ready to dig the pond. When you have finished, get rid of the soil and leave a clear 1-1 1/2 wide strip all around the edge of the hole. Check the level again, adding or removing soil as needed. The beauty of the flexible pond liner is that it is still possible to tuck a little extra soil under the edge or remove any surplus even after the liner is in place and the pond is filled with water.

To avoid leaks later, pick out visible stones or large roots from the sides that could perforate a butyl or PVC liner, once the weight of the water presses it down. It is also advisable to cushion the liner more, so spread a 2-inch layer of damp in the bottom. Where the ground is stony, use a special pond underlay (ask for bonded fiber). This will stop flints and roots from getting through. Put a layer of sand on top of this also. Use the bonded fiber on its own in places where you cannot "plaster" the inside of a pond shape with sand.

EQUIPMENT NEEDED

• 40 foot of 4"x4" timber (tannalized), which will probably come in four 10-foot lengths, which we will be cut into 6-foot and 4-foot lengths
• Stake and string, if making round pond
• long rope or hose, if making free-form pond
• Hammer
• 6" nails
• Saw
• Level
• Trowel
• Submersible pump with cable (450 - 550 gallons per hour)
• Conduit for cable and circuit breaker
• Four bags of soft sand 2' x 15"
• 1 bag of pea gravel 2' x15"
• Watering hose to reach pond.
• Possible pond underlay if ground has roots and rocks.
• Plasterer's float