Providing the perfect home for some of the most decorative foliage and flowering plants, a pond also mirrors the sky, reflecting light into the garden. A wildlife pond is especially beautiful, and will also attract a whole host of beneficial animals, birds, and insects. Make one with sloping sides, to allow easy access for creatures to come and go, and leafy edges that offer habitats and cover. Site your pond in an open area, not too near overhanging trees because decaying autumn leaves sully the water.
When to start: Late winter or early spring.
At their best: Spring to early autumn.
Time to complete: 2-3 days.
You will need: Hose, spade, long length of wood, spirit level, old carpet or pond underlay, butyl pond liner (see Step 1 for quantities), sharp knife, large stones, mortar, trowel, pond plants, aquatic soil, pond baskets, gravel.
Mark out the pond
Using a hose, mark out the pond with sweeping curves for a natural effect. Calculate the area of liner you will need by adding twice the total depth (D), plus 18 in (45 cm) extra, to the length (L). Then add twice the depth (D), plus 18 in (45 cm) extra, to the width (W), and multiply the two answers (see also Step 2 below): (2xD+18 in+L) x (2xD+18 in+W).
Dig down
Dig out the whole area of the pond to a depth of 18 in (45 cm), and angle the sides so that they slope slightly. Leave a 12–18 in (30–45 cm) wide shelf around the sides at this depth. Then dig out a central area 3 ft (1 m) deep, and an adjacent area, about 30 in (75 cm) deep, creating two deeper areas to keep plants and wildlife frost-free in winter.
Level
It is essential that the top edges of the pond are level all the way round, or water will drain out unevenly. Place a spirit level on a straight plank of wood and test the level in six or seven different places, building up or removing soil as necessary.
Line the base
Smooth the edges, and remove large or sharp stones from the sides and base. Line the pond with old carpet or a special pond underlay. Do not use sand because it falls away from the sides and will fill up the hole.
Line with butyl
Center the liner over the hole and push it down in the middle, allowing pleats to form against the sides and base. Fill the deepest part with water; the weight will pull the liner into place.
Fill with water
Fold the liner in neat pleats over the shelf and top edges, and check that it is bedded into the bottom of the pond. Top up with more water, which will force the liner against the shelf and sides.
Trim to fit
As you fill the pond, move around so that the liner is pulled evenly into the hole. When the pond is full, trim the liner with a sharp knife, leaving up to 18 in (45 cm) excess around the edges.
Edge with turf or stones
To turf up to the edges, leave 10 in (25 cm) of excess liner and butt the turves up to it. Or add stones by mortaring them onto the liner, making sure no cement falls in the water in the process.
Place the stones
When positioning the stones, make sure that they do not overhang the edge by more than 2 in (5 cm). This will prevent them from tipping up and both you and the stones falling into the water when you walk on the edge.
Finish off
Place rocks in the water but protect the liner from damage by placing them on cushions of folded plastic sacks or spare rolled-up liner. Ensure the rocks are stable, but do not mortar them in. The pond is now ready to plant. Use the shelves around the sides for marginal plants, and the deeper areas for submerged aquatics, such as water lilies.
Tips: Choosing pond plants
There are four main types of pond plant; deep-water aquatics, oxygenators, marginals, and bog plants. Water lilies are deep-water aquatics and sit on the bottom of the pond, although some will grow in shallow water. Check the depth required on the label (measured from the pot surface) and raise them up on bricks as required.
Oxygenators are essential plants that help keep the water clear. Marginals, such as the marsh marigold, Caltha palustris, prefer the shallows around the edge of the pond, and will be happiest on the shelf. Site bog plants in the damp area around the pond—not in the water.