Customers at the garden centre frequently tell me that one of their greatest joys in the garden is their pond. They just love to watch the fish, the frogs, and the other forms of wildlife from waterboatmen and pond skater insects, to dragon and damselflies.

And if they’ve installed a pump, there’s the relaxing sound of a trickling fountain or cascade of water tumbling over well-placed stone. Tranquil. Peaceful. Calm. Deep breath – breathe out: aaaaahhh!

But before you can enjoy the gin and tonic next to your mini-version of the Trevi Fountain, you need to install it.

“Yes, I’m going to have a pond!” It’s a familiar cry in many a household. “And I’ll put it there-I’ll dig a hole, get some of that liner stuff, put it in the hole and fill it with water.

The fish will be in by the end of the weekend, and we’ll have waterlilies in flower by March!”

Yeah, right!

It’s all very well living in cloud cuckoo land, but that ‘liner stuff’ needs some thinking about. So, before you do anything, consider the options.

Rigid moulded liners made from vacuum-formed plastic are widely available and popular, but you are very restricted as to the shape and size of your pond, and digging the hole and levelling the rigid liner is a monotonous process. Concrete ponds are an alternative, but concrete has largely had its day, and making one takes a great degree of skill, time and hard labour.

Flexible liners are the best option for many. These are basically waterproof sheets, available in pre-cut sizes in packs, or on rolls from the garden centre where you can take any length to suit. The best reliability comes with rubber sheeting (known as butyl), and the wonderful thing about flexible liners is that they enable you to build a pond of any shape or size.

Both knowing where to site the pond, and digging the hole for it are fairly straightforward stages in its construction. But perhaps the first real obstacle comes when you have carried out both of these, and are now loitering in the garden centre aquatics section, agonizing over how much liner to buy!

It is crucial that you get enough liner, as joining two bits together is difficult (although not impossible), expensive (you’ll need at least 50g of liner glue per metre of gluing seam), and pretty much opens up the field for leaks in future years.

Installing a flexible liner is not that difficult:

*Stay with gentle curves and simple shapes. Avoid sharp corners and fussiness.

*Both gently sloping and straight vertical sides can also cause problems, so it is better to aim for 20° sides.

*Remove any sharp stones or rubble from the sides and base of the pond, and tread the area well to firm it. Line the hole with 5cm (2in) of damp sand, or use a pond underlay.

*Unfold the liner, and allow it to sag into the hole, then lightly anchor it with a few large rocks or slabs around its edge.

*Slowly fill the liner with water, and as it takes the weight of the water, adjust it into neat folds, but do not pull or stretch it.

*Leave the liner to settle overnight, and then trim the edges to the shape of the pond, leaving at least 30cm (12in) overlap for anchorage. The pond is now ready for edging, planting, and so on.

Here’s a tip for anyone about to install the liner but have discovered that they have run out of it by just a few inches: gain back these inches by packing the bottom of the hole (beneath the liner) with sand. This will slightly raise the base of the pond, which probably isn’t too important, and will save you from having to start all over again!

Finally, these flexible liners are available in different thicknesses, and this can be important if your pond is large, for the high volume of water would put a lot of pressure onto a thin liner, and therefore has the potential for shortening its life.

Use this handy guide to help you select the right thickness of liner:

*Ponds under 10m2: 0.5mm liner

*Ponds up to 1.5m (5ft) in depth: 1.0mm liner

*Ponds more than 1.5m (5ft) in depth: 1.5mm liner

The science (for that is what it is) of installing a pond is not straightforward – but the rewards are long-lasting and manifold. Happy gardening!

source : iccroydon.icnetwork.co.uk