Why a pond is the best thing you can build for wildlife

Few garden features repay the effort so generously. Within a season or two, a well-made pond becomes the busiest square metre of the plot: frogs arriving at dusk, damselflies resting on iris leaves, newts surfacing for air, and a shifting cast of birds, bats and hedgehogs coming down for a drink. Our native frogs and dragonflies are in decline largely because we have drained and tidied away their breeding sites, so a pond in a rural garden is a genuine act of conservation. It is also, frankly, a lovely thing to sit beside with a mug of tea.

The good news is that a wildlife pond is cheaper and less fussy than a koi pond. No filters, no pumps, no feeding, no chemicals. Just water, plants, and a bit of patience.

Choosing the right spot

Dragonflies need warmth, so aim for at least five or six hours of direct sun a day. Frogs are more cautious and appreciate a shaded edge or nearby cover to retreat into, so a position in part sun is ideal. Keep the pond away from overhanging trees — falling leaves add nutrients, and roots can puncture a liner — and avoid the lowest point of the garden if it sits below a lawn or arable field, where fertiliser and pesticide run-off will drain straight in.

Placement matters for people too. A pond should be visible from a window or a bench, otherwise you will not notice what is living in it. If you have toddlers, either fence the pond or design it with a wide, shallow shelf and a gentle pebble beach that gives an easy way out. On the whole, a garden pond does not require planning permission, but do check if you rent or live in a listed property.

Digging, shaping and lining

Aim for a maximum depth of 60–80cm in the centre, which keeps frogs and newts safe below the frost line, with a broad shelf at 20–30cm for planting and for wildlife to enter and leave. Sloping sides are far better than vertical ones. Irregular, kidney-shaped outlines with a wavy edge look natural and create sheltered pockets of still water.

For lining, butyl rubber is the most durable and forgiving; EPDM is a good second, and rigid pre-formed shells suit very small ponds. Whatever you choose, lay a geotextile underlay or old carpet beneath it, and leave a lip of liner extending 15cm or more beyond the water level, buried under turf or hidden with stones. Build at least one gradual ramp of pebbles or gravel so hedgehogs, amphibians and insects can climb out.

Fill the pond with rainwater collected from a water butt or roof rather than tap water, which carries nutrients and encourages algae. If you must use the hosepipe, let it stand for a few days before adding plants.

Planting for frogs, newts and dragonflies

Think in three layers, and use native species wherever you can. Buy from a reputable aquatic nursery — never take plants from the wild, as you risk introducing disease and invasive species.

• Oxygenators: hornwort, water starwort and spiked water-milford sit below the surface, keep the water clear and provide spawning sites for frogs and newts.
• Floating and deep-water plants: a modest water lily or frogbit gives shade, shelter and a landing pad for dragonflies to rest on.
• Marginals and emergents: marsh marigold, water forget-me-not, brooklime, lesser spearwort, yellow flag iris and purple loosestrife. These are the stems dragonflies use to climb out when they emerge from their nymph cases.
• Avoid: floating pennywort, water fern, parrot's feather and other invasive species that can smother a pond and spread to nearby waterways.

Keeping the water clear without harming wildlife

Green water in a new pond is completely normal and usually clears by the second or third summer as plants establish and shade the surface. Resist the urge to fix it chemically. Never use algicides, dyes or fertilisers near the pond, and never introduce fish, which eat tadpoles and stir up the silt.

• Top up with rainwater in dry spells, never tap water if you can help it.
• Twirl blanketweed out on a stick in summer and leave it on the edge overnight, so any trapped creatures can crawl back in.
• A mesh bag of barley straw, floated in spring, is a traditional and gentle way to limit algae.
• Skim some autumn leaves, but leave a few — newt larvae and dragonfly nymphs shelter among the debris at the bottom.

A gentle year of care

In spring, thin out plants that have romped away and check the liner edge is still tucked in. Through summer, enjoy the arrivals — a frog will usually find a new pond within a season, and dragonflies within two or three. In autumn, leave seed heads and dying stems standing; they are next year's habitat. In winter, never break ice with a hammer, as the shock can kill overwintering amphibians. Float a ball or rest a pan of hot water on the surface instead. The pond you build this spring will be thick with life by this time next year.