Why a pond is the best thing you can add to a garden

Few garden features repay the effort quite like a pond. Within weeks of filling one, you will usually see the first water beetles rowing about, and by the following spring you may have frogs, newts and a resident pair of damselflies. Even a modest pool — a couple of metres across — becomes a genuine habitat, a place where creatures that have nowhere else to go can breed, drink and shelter. In a countryside of tidy fields and fenced-off water, garden ponds have quietly become one of the most valuable refuges for British wildlife.

You do not need a large plot, heavy machinery or any great expertise. You need a patch of ground, a liner, rainwater, and the patience to let nature do most of the planting. A wildlife pond is not a koi pool with a filter; it is a living, slightly scruffy thing, and it is all the better for it.

Choosing the right spot and size

Position matters more than size. Aim for somewhere that gets sun for part of the day and shade for the rest — a pond that bakes all afternoon will grow green algae with enthusiasm and support little else. Avoid sitting it directly beneath deciduous trees, where falling leaves will rot and strip the water of oxygen, though a nearby hedge or mature shrub is a bonus, giving frogs a damp corridor to travel along.

As for scale, a pond of about two metres by three is generous enough to be self-sustaining. Anything from one metre across will still attract life, so do not be put off by a small garden. Keep the edges irregular rather than a perfect circle, and gently slope at least one side so that hedgehogs, birds and amphibians can walk in and out safely. Steep, slippery sides are a death trap for small creatures.

Digging and lining: getting the structure right

Mark out your shape with a rope or a length of hosepipe, then dig in layers. The design that works best has three zones:

• A shallow shelf around 20–25cm deep for marginal plants.
• A deeper central section of 60–75cm, which stays unfrozen at the bottom and gives frogs and newts somewhere to overwinter.
• A gradual beach or ramp on one side, so wildlife can enter and leave with ease.

Remove sharp stones and roots, then lay a soft underlay before the liner — butyl rubber is durable and straightforward to work with. Leave a generous overhang around the edge; liners always shrink more than you expect. Fold the surplus into the margins and disguise it with turf, stones or a planted bank.

Fill the pond with rainwater from a water butt if you possibly can. Tap water contains nutrients and minerals that encourage algae, so if you must use it, let it stand for a few days first and expect a green flush in the early weeks. That first murky phase usually clears on its own once plants and microscopic life settle in.

Planting up for clear water and cover

Plants are the engine of a healthy pond. Aim for roughly half the water surface covered at maturity, using a mix of submerged oxygenators such as hornwort and water starwort, marginals like marsh marigold, water forget-me-not and ragged robin, and one or two floating plants for shade.

Buy native species and plant them in baskets of loam to stop them taking over. Be firm about what you refuse: Canadian pondweed, floating pennywort, parrot's feather and water fern are invasive and will smother everything. Avoid introducing fish, too — they eat tadpoles and stir up the silt, and a wildlife pond is far richer without them.

Welcoming frogs, newts and dragonflies

Much of the wildlife arrives by itself, but you can make the surrounding garden more inviting. Leave a patch of long grass nearby, build a small log pile in the shade, and resist the urge to tidy every corner. Frogs and toads will use damp, dark refuges through the summer, and newts will hide beneath stones and bark.

Dragonflies and damselflies need vertical stems to emerge from as adults, so let irises and rushes stand. Birds will visit to drink and bathe, so a shallow, gently sloping edge is a real asset. If you are lucky enough to find great crested newts, they are legally protected — enjoy them from a distance and never move them.

Caring for the pond through the year

Less is very much more. In spring, twirl blanketweed out with a stick and leave it on the bank overnight so trapped creatures can crawl back. Net out fallen leaves in autumn, but never empty and scrub the pond — that silty layer is alive with larvae and eggs. Cut back no more than a third of the marginal growth in any one year, and leave seed heads standing for the birds. Avoid all pond chemicals, and top up with rainwater during dry spells.

Do that, and within a season or two your pond will be humming with life — a small, vivid patch of British countryside right outside the kitchen window.