How to construct a pond – secrets of success with water

 

Water is the magic ingredient in any garden, large or small. A pond, rill, stream, bowl, or any type of water feature adds another dimension to the garden picture. Still water adds depth and reflection and changes with the light and the sky. Moving water adds life and gentle sound, distancing the garden from the outside world. Although you do not have to construct a pond to bring water into your garden, if you can include one it will enable you to grow a whole new range of plants, possibly keep fish, or attract a great variety of wildlife into your garden.

Pond construction may sound daunting, and it usually does involve some digging, however your pond does not need to be vast. Even a small shallow pool will work its magic,that is if you go about it in the right way. Creating a pond does involve some work and it will demand modest investment so make sure you do it well and that your pond becomes the feature it should be and enhances your garden. So often, what should be something beautiful is spoilt by careless construction. So here are a few things you should consider before you start and during construction.

1. The surface of water will always be completely horizontal, so it is important to get your levels right at the outset. This may sound obvious, but I often see pools constructed on sloping sites where this has not been considered, exposing the liner on the uphill side of the pond.

2. If you have a choice site your pond in an open sunny position away from overhanging trees. Waterlilies and other water plants need sun to thrive and leaf fall can be a real problem.

3. Always use a top quality pond liner. Personally I would not consider anything apart from the best quality rubber liners. There are usually two grades available: thicker rubber liners available from Swell UK such as Gordon Low Firestone Pond Liner  which will last a lifetime and are definitely the best choice for larger ponds, and the thinner more flexible ones such as Gordon Low Greenseal Pond Liner are ideal for smaller ponds where contours are more difficult and for streams and cascades where the liner has a more restricted space to line.

4. Always use the proper underlay for the pond liner. Various sources will recommend old carpets, layers of newspaper and the like. Carpet is difficult to mould to the contours of shelves and the bottom of the pond and the liner needs to follow the lines you want with as few creases as possible. Once you’ve used pond liner underlay you will never use anything else.

5. At the outset consider how you are going to hide the edges of the pond liner. You either need to use an edging with an overhang, or you need to bury the edges of the liner and run them under the ground for 30cm (1ft) or so if your pond is running straight into grass. This is trickier and your levels need to be perfect.

6. If constructing formal pools with square corners you will have more major folds in the liner in the corners of the pond. You will need to conceal these with sufficient overhang of paving.

7. Consider the depth of the pond at the outset. If you are going to keep fish and want to grow lilies you need a depth of 90cm (3ft) in the centre of the pond; ideally. This does vary according to where you are. If winters are cold, go deeper; you may get away with a shallower pool in milder regions.

8. In any pond over 30cm (1 ft) deep you need to construct the pond with shelves around some or all of the sides. These should be around 30cm (1ft) wide to allow for planting baskets containing marginal plants, These not only look good but they are essential for the life cycle of many beautiful insects such as dragon flies.

9. If you are constructing a wildlife pond, a shallow beach along at least one edge of the pond is essential. This is constructed by running the liner, at a gradual gradient, under flat stones, slate scree or pebbles. Avoid anything with sharp edges that could puncture the liner. The beach will be used by birds and animals visiting the pond to drink; it will also provide an escape route for anything that falls in inadvertently.

10. In a larger pond fish, wildlife and plants may live together reasonably happily, you may also have space for a fountain or cascade at one end and lilies at the other. In smaller ponds you will have to decide what you want. Waterlilies dislike the splash of a fountain; fish and wildlife are not always that compatible.

Constructing your pond

Finally do take your time constructing your pond; it is going to be a permanent garden feature so you need to get it right. Make sure the hole you have made is perfect and there are no stones protruding. Make the hole 10cm (4”) deeper and wider than you want the finished pond to be to allow for a generous layer of and over the base, into the corners and up the lower edges of the sides to smooth out the lines. Get your underlay in position: dampening it may help to hold it. Stretch the liner over the hole and anchor with flat, smooth stones (wrap them if necessary). Then start to fill with water from the centre of the liner – slowly. This allows the water to mould the liner to the contours of the pond: help it! If necessary encourage more small pleats in the liner: they are easier to hide than big ones.

Don’t cut off excess liner from the edges until you are sure you have your levels right and that you are going to be able to hide the edges of the liner. If you’ve got it wrong this is really your last chance to drain the pond and rectify any errors. This is another advantage of using a good quality flexible liner: it will cope with double handling. Cheap PVC liners are easily damaged and certainly become brittle with age. They are far more likely to be punctured by any stones you’ve missed!