A Beginner's Guide to Planting a Wildlife Pond

Start With the Right Spot

A pond is the single best thing you can add to a garden for wildlife. It doesn't have to be large — even a sunken washing-up bowl will draw in frogs and insects — but a small pond of roughly 1.5m by 1m will support far more life for very little effort.

Site it where it gets sun for at least five or six hours a day. Dragonflies need warm, open water to bask over, and most pond plants flower poorly in shade. A little dappled shade in the afternoon is no bad thing, though, as it keeps the water cooler and slows the algae.

Keep the pond away from trees and big shrubs. Fallen leaves sink and rot, feeding algae, and roots can puncture a liner. Avoid the lowest corner of the garden if it collects runoff from roads or fields, which carries nutrients and pollutants. Level ground is easiest, and somewhere you can see from a window is a real pleasure.

Digging In: Size, Depth and Shape

Go as large as your space and your back will allow, but remember that depth matters more than width. Aim for at least 60cm at the centre so the pond doesn't freeze solid in a hard winter and frogs, newts and larvae can overwinter in the mud at the bottom.

Build in ledges as you dig. A shelf about 20–25cm below the waterline suits marginal plants, and a deeper shelf at around 45cm takes taller marginals and oxygenators. Slope the sides gently and leave one shallow beach so hedgehogs, frogs and drenched bees can climb out. A steep-sided pond is a death trap; a piece of roughened wood angled into the water makes an easy ramp.

Line the hole with a geotextile underlay and then butyl or EPDM rubber, tucking the edges under turf or stones with at least 30cm of overlap all round. Fill with rainwater from a butt if you can; tap water contains chlorine and nutrients, so let it stand for a few days first if you have no alternative. The pond will look like a muddy puddle for a fortnight before it clears, which is entirely normal.

Planting Natives at Every Depth

Plants are what turn a hole full of water into a habitat. Buy from a specialist native aquatic nursery, or ask a friend with an established pond for divisions, and never take plants from the wild.

• Marginals for the shallow shelf: marsh marigold, water forget-me-not, water mint, lesser spearwort and ragged robin.
• Taller accents: yellow flag iris, purple loosestrife and soft rush — keep them in baskets so they don't overwhelm a small pond.
• Oxygenators: hornwort, water starwort and curled pondweed, which grow below the surface, compete with algae and give tadpoles somewhere to hide.
• Floating cover: a small clump of frogbit or water soldier.

Plant marginals in aquatic compost in hessian-lined baskets. Ordinary garden soil or potting compost is far too rich and will turn the water green. Oxygenators can simply be dropped in, weighted with a stone. Aim to cover no more than half the surface by midsummer, leaving open water for dragonflies and birds.

Avoid invasive plants altogether. Floating pennywort, parrot's feather, water fern and New Zealand pygmyweed can escape a garden pond into the wild, and it is an offence to plant or cause some of them to grow there.

Leave the Fish Out

The most valuable decision you can make is to keep fish out. Even a few goldfish will clear a pond of tadpoles, dragonfly larvae and water beetles within a season, and they stir up sediment until the water is permanently cloudy. A wildlife pond needs no pump, no filter and no feeding. If you already keep fish, enjoy them, but treat that as a separate pond with separate rules.

What Will Turn Up

Be patient, and then be pleasantly surprised. Water beetles, pond skaters and other insects arrive on the wing within weeks. Frogs and newts generally find a new pond in the first spring, while toads take a little longer. Dragonflies and damselflies follow once there are plants to perch on — common darter and broad-bodied chaser are often the first. Birds will drink and bathe at the shallow edge, blackbirds, sparrows and blue tits among them, and hedgehogs and bats visit at dusk to drink and hunt insects.

Looking After It Through the Year

• Spring: twirl excess blanketweed out with a stick and leave it on the edge for a day so trapped creatures can crawl back. Keep chemicals and slug pellets well away from the pond and its border.
• Summer: top up with rainwater in dry spells, but keep the level about 10cm below the liner edge so amphibians aren't washed out.
• Autumn: net out fallen leaves before they sink and rot. Never empty and scrub the pond, which destroys the whole community in one afternoon.
• Winter: leave dead stems and seed heads standing for overwintering larvae and sheltering birds. If the surface freezes, float a ball or a pan of hot water on it to keep a patch open, and never smash the ice, which shocks the animals below.

Finally, leave a wild corner nearby. A log pile, a patch of long grass and a few nettles will make the pond work harder still, and within two or three years it will be the busiest part of the garden — and easily the best place to sit with a mug of tea.