Why a small garden pond matters in the countryside

A pond the size of a dining table can be the busiest patch of habitat in a rural garden. Ponds have been lost from the British countryside at a startling rate — drained for fields, filled in for paddocks, left to scrub over — so what you dig behind the hedge genuinely counts. Frogs, common newts, damselflies, water beetles and a long list of hoverflies and bees will find it within a season or two. You don't need an acre, a pump or a filter. You need a shallow edge, native plants, and the patience to let it find its own balance.

If you garden on heavy clay you may be able to puddle the base and skip a liner altogether. Most of us won't be so lucky, so a butyl or EPDM liner, or a rigid pre-formed shell, is the practical answer.

Choosing the spot: light, roots and a gentle slope

Choose somewhere with at least five or six hours of sun a day. Warm water means more insect life, earlier frog spawn and stronger plant growth. Full shade gives you a cold, lifeless puddle; deep midday shade under a mature oak is worse still, because the leaves drop straight in and rot.

• Avoid mature trees and shrubs, for leaf fall and for roots that will pierce a liner.
• Avoid the lowest point of the garden, unless a bog is precisely what you want — which is a fine ambition in itself.
• Avoid anywhere that takes run-off from a road or yard, where silt and pollution collect.

Leave one side sloping gently to the water's edge rather than cutting a sheer drop. That ramp is what lets a hedgehog climb out, a fledgling drink, and a toad walk in without drowning.

The shallow ledge is the whole trick

If you remember one piece of pond design, make it this. Along at least one side, build a shelf 20–30cm deep and 30cm or more wide. Set the centre at 60–75cm, deep enough for frogs and newts to overwinter in the silt below the frost line without the whole thing freezing solid.

The ledge does three jobs. It gives amphibians somewhere to haul out and bask. It lets you plant the marginal species that provide cover and egg-laying sites. And it keeps much of the pond warm and shallow, which is exactly where the life is. Roughly a third shallow, a third ledge and a third deeper water works well for a pond of two metres by one and a half.

Planting native: structure beats a tidy border

Fill the pond with British natives and it will largely look after itself. Aim for three layers.

• Submerged oxygenators — hornwort, water starwort and curled pondweed. These compete with algae for nutrients and give newts somewhere to hide and lay eggs.
• Marginals on the ledge — water forget-me-not, brooklime, marsh marigold, water mint and ragged robin. Bees and hoverflies work these all summer.
• One or two statement plants — purple loosestrife or yellow flag iris, kept in a basket so they don't march across the whole pond.

Plant in aquatic baskets lined with hessian and topped with washed gravel rather than ordinary compost, which releases nutrients straight into the water. Resist non-native floaters such as water hyacinth or parrot's feather; they can escape and cause real trouble in the wider countryside.

Water, algae and leaving well alone

Fill it with rainwater from a butt, not tap water. Tap water carries nutrients and, in hard-water areas, plenty of lime; both feed the algae you don't want. Rain off the roof is free and soft.

Expect green water in the first spring. It's a stage, not a failure. As plants establish and shade the surface, the algae lose their light and the pond clears on its own, usually within one growing season. Don't drain and scrub it — the tiny life in the silt is the foundation of everything else.

The single most useful decision is to put no fish in. Even a few goldfish will hoover up frog spawn, tadpoles, newt larvae and almost every insect that lands. A fish-free pond is a wildlife pond.

Winter, top-ups and a few small kindnesses

Top up in dry spells with rainwater, a little at a time, and keep the level a few centimetres below the rim so amphibians can move in and out. In autumn, net out some fallen leaves but leave a few — they feed the whole detritus cycle. Clear excess blanket weed in late summer with a stick, and leave what you pull on the pond edge for a day so shrimps and beetles can crawl back in.

Before winter, float a couple of small logs or a bundle of twigs on the surface. They keep the pond from sealing over with ice and give frogs somewhere to sit during a mild spell. Leave a pile of stones, dead wood and long grass nearby, and the frogs, newts and hedgehogs that use your pond will have somewhere to spend the rest of the year.

Then do almost nothing. That's the beauty of it: a well-built garden pond rewards a certain amount of neglect, and the frogs usually arrive long before the landscaping is finished.