Adding a pond to your garden is the single most important thing you can do to attract more wildlife. Below is an example of a typical garden pond, followed by a step-by-step guide to getting started, then a look into the underwater world you can create.
This pond at RHS Hyde Hall has now been been replaced, but it's a good example of how an average-sized pond could look. It would take a couple of people about two weekends to complete the construction.
Step 1 - peg out the outline, or use spray paint and adjust until you are happy with size and shape.
Step 2 - If you¹re digging in a grassed area, cut away the turves and dig your hole. The pond shape (round, oval, square or irregular) is not critical for wildlife, it is more important that it looks right for your garden.
Step 3 - To maximise biodiversity, if there is room, have several basins of differing depths. Make sure you have lots of shallow water less than 10cm (4in) deep by including gently sloping edges, or wide shelves as here (also ideal for marginal plants), these areas support the most wildlife. Unless you are adding fish, the pond need be no deeper than 30cm (12in).
Step 4 - Remove any sharp stones in the hole. Lining it with something to protect the liner is recommended – either a layer of a few cm of soft sand, old carpets or underlay, or proprietary liner protector (or both).
Step 5 - Apply the sand layer uniformly over the sides and base of the hole. Check the edges are level all the way round with a plank and spirit level, adjusting the lips where necessary. Check also for protruding sharp stones.
Step 6 - Compress the sand by gently treading the surface to give the liner a firm bed. Spread the liner protector out over the layer of sand.
Step 7 - Spread the pond liner out so it covers the excavated area, and leaves enough to overlap on all sides. Don’t worry too much about creases; the weight of water will push the liner into the hole, and once the pond is full they will hardly be noticeable.
Step 8 - Fill the pond with your stored rainwater (the hose below is from a rain-fed reservoir). In the shallows, use washed play sand and washed gravel, into which plants can root, to cover the liner. Even gravel and sand sold as ‘washed’ is often quite dirty, and that dirt may contain nutrients – wash it again to get it as clean as possible.
Step 9 - Trim the liner to the shape of the hole but leave it 20–30cm (8–12in) bigger all around. Concealing the liner is tricky: you may have to wait until it is gradually covered by silt and vegetation as the pond matures.
Step 10 - Add plants. Native water plants (from specialist suppliers) will colonise naturally over time. These can simply be thrown into the pond - they will anchor themselves in a month or two. If you want marginals in specific places, weigh each down with a stone. If plants are in bespoke aquatic planting baskets (like this native yellow flag iris) discard compost, replace with a clean washed sand & gravel mix.
Step 11 - Fleece-like matting that encourages water plants and mosses to grow over it is available specifically for the water edge. Alternatively, cover edges with paving or turves. For a natural edge in grass, slice under the turf around the pond margin, lift it and tuck the liner under, but don’t cut the turf away completely from the surrounding lawn. It may go brown briefly but will soon green up.
Underwater world - Do a pond-dip three months later to find out how well your pond is doing – you will be amazed how quickly aquatic animals arrive, seeming to come from nowhere.
It will not take long for the pond to begin to attract species such as birds, amphibians and even bats in addition to the myriad insects. Most garden ponds attract frogs, which will often spawn there; other amphibians that may colonise include toads and newts.