Why a Pond Beats Almost Anything Else You Can Do for Wildlife

If you only ever make one change to your garden for wildlife, make it a pond. Nothing else comes close for the sheer number of creatures it brings in. Frogs and newts will find it within a season, often within weeks. Dragonflies and damselflies will patrol it on warm afternoons. Birds will use it for bathing and drinking, hedgehogs will come for a night-time drink, and the water itself will fill with boatmen, water beetles, pond snails and all manner of tiny life you never knew you were missing.

The good news is that a wildlife pond does not need to be big, formal or expensive. A hole roughly two metres by one and a half, lined with rubber and filled with rainwater, is a genuinely excellent pond. Scruffy is fine. In fact, scruffy is better.

Choosing the Right Spot

Position is the one decision you cannot easily change later, so give it some thought before you pick up a spade.

• Sun for at least half the day. Dragonflies, damselflies and most aquatic plants need warmth. A pond in deep shade will sulk and stay lifeless.
• But not full sun all day. In a small pond, baking sun encourages blanketweed and green water. Dappled shade from a deciduous shrub is ideal.
• Well away from trees. Leaves and blossom drop in, rot, and feed the algae. Roots, especially from willow and poplar, can puncture a liner.
• Clear of runoff. Keep the pond away from patios, driveways and treated timber, so that fertilisers, weedkillers and cleaner never wash in.
• Somewhere you can see it. Put it where you will pass it daily and can watch from a kitchen window. A pond you notice is a pond you look after.

Depth, Shape and Lining: the Practical Bits

A good wildlife pond has three zones, and the shape matters more than the size.

• A shallow shelf at 20–25cm. This is where marginal plants sit, where birds bathe, and where hedgehogs and frogs can safely enter and climb out.
• A deeper section of 60–75cm. Frogs, newts and dragonfly larvae overwinter in the mud at the bottom. In most of Britain this depth will not freeze solid, which is exactly what you want.
• Gently sloping sides. Vertical walls look tidy but drown wildlife. Aim for at least one long, gradual slope.

Butyl rubber, at least 1mm thick, is the sensible choice for a lined pond. Lay it over a fleece underlay or a layer of old carpet to protect it from stones. Dig the hole with a spirit level on hand, and allow a good 30cm of liner overhang all round to tuck under turf or paving. Fill with rainwater from a water butt if you possibly can. Tap water is full of nutrients and will green up fast; if you must use it, let it stand for a day or two first, and expect the pond to look like soup for a few weeks before it clears.

Planting for Wildlife, Not Just Looks

Use native plants where you can, and aim to cover roughly a third of the water surface so the pond stays shaded but not smothered.

• Oxygenators: hornwort, water starwort and spiked water milfoil live below the surface and keep the water clear, while giving larvae somewhere to hide.
• Marginals: marsh marigold, water forget-me-not, lesser spearwort, flowering rush and yellow flag iris along the shallow shelf. Plant them in baskets of ordinary garden soil topped with gravel, not compost, which leaks nutrients.
• Floating cover: a native water lily, or simply frogbit, provides shade and a resting place for emerging froglets and dragonflies.
• Emergents for dragonflies: leave iris and rush stems standing through winter. Dragonfly larvae climb up them to split open and emerge as adults.

Do avoid the invasive thugs, including New Zealand pygmyweed, floating pennywort, water fern and parrot's feather. Several are banned from sale and it is illegal to let them spread into the wild. Never tip pond plants into a stream or canal.

And do not add fish. Goldfish and koi will eat frogspawn, tadpoles and almost everything else. A wildlife pond is far more interesting without them.

Edges, Ramps and Safe Access

Most pond deaths are not drownings; they are animals that got in and could not get out. A little thought here saves a great deal of heartache.

• Build a gently sloping shingle beach at one end, so anything that falls in can simply walk out.
• Add a rough log or stone ramp if your sides are at all steep, and leave it in place year-round.
• Float a few pebbles or a shallow tray at the edge for birds to bathe in safety.
• Plant dense ground cover within a metre of the water, so froglets and newts have somewhere to hide as soon as they leave.
• Stack a small log pile or stone heap nearby for shelter and hibernation.

If you have toddlers, a raised pond or a rigid mesh grille that lifts off for maintenance is the safer option, and will still attract everything you want.

Seasonal Care: Far Less Work Than You Think

Spring is the exciting bit. Watch for frogspawn in February and March, and clear duckweed with a net before it takes hold. Resist the urge to tidy every stem; the dead growth from last year is habitat.

Through summer, top up with rainwater rather than tap water. A pond can lose a couple of centimetres a week in hot weather, and a sudden drop in level leaves spawn and tadpoles stranded.

In autumn, net out some of the fallen leaves, but not all of them. A few are food and cover. Too many will rot and starve the water of oxygen.

In winter, never smash the ice. The shock waves can kill the creatures below. Float a ball in the pond, or melt a small hole with a pan of hot water set on the surface, to let gases escape.

Above all, be patient. A new pond usually looks like a jar of green soup for its first season, and then it finds its own balance. The frogs, newts and dragonflies will arrive on their own, without any help from you. All you have to do is dig the hole, and then sit back with a cup of tea and watch it fill up with life.