Encouraging frogs and newts in your wildlife pond

Why a wildlife pond is worth the effort

Few garden projects repay you as generously as a pond built with amphibians in mind. Common frogs, common toads, smooth newts and palmate newts are all struggling in the wider countryside as ponds are filled in and ditches dry up, yet they will happily colonise a well-built garden pool. Give them somewhere to breed and you get free pest control in return — a single frog can account for dozens of slugs a night through the growing season.

The trick is that amphibians are fussy in very specific ways. They need shallow, sun-warmed water for spawning, gentle banks so young froglets can climb out, plenty of leaf cover to hide in, and a steady supply of insects. Get those four things right and the rest takes care of itself.

Designing a pond that frogs and newts can use

Aim for a pond that is at least two metres across if space allows, with a maximum depth of 60–90cm in the centre. That depth keeps the water cool in summer and stops the whole thing freezing solid in a hard winter, which matters because frogs often overwinter in the mud and leaf litter at the bottom.

The single most important feature is the profile of the banks. Steep, vertical sides are a death trap. Build in at least one gently sloping side — a gradient of around 1:4 is ideal — and include a shallow shelf of 10–20cm depth along part of the edge. This is where frogs will spawn in February and March, and where newts will court and lay. Frog spawn needs sun to develop, so make sure that shallow shelf sits in the open rather than under overhanging branches.

A butyl or flexible liner is usually the easiest option for a curved, gently graded shape. Line it with a generous layer of soft sand or old carpet underneath, then finish the edges with turf, cobbles or pebbles so amphibians have something to grip as they haul themselves out. If you already have a rigid pre-formed pond, you can still make it work — simply sink a shallow gravel beach alongside it or add a sturdy ramp of roughened timber.

Choosing native plants that do double duty

Plants give cover, shade, egg-laying sites and a supply of insects. Stick to British natives where you can, and plant in generous clumps rather than single specimens.

• Water forget-me-not and brooklime — newts wrap their eggs individually in the leaves of these, folding them over with their hind legs.
• Water starwort and hornwort — oxygenators that float near the surface and give tadpoles somewhere to hide.
• Marsh marigold and lesser spearwort — early flowers that bring in pollinators and provide cover at the water's edge.
• Water mint — a magnet for hoverflies and small insects, which is exactly what frogs sit and wait for.
• Yellow flag iris and purple loosestrife — taller structure around the margins, useful for emerging froglets.
• Ragged robin — excellent in the damp soil just beyond the pond edge.

Avoid covering more than about half the water surface with floating plants, and keep an eye on duckweed, which can quickly blanket everything and starve the water of light and oxygen.

Shelter, refuges and a safe route in and out

Amphibians spend far more time on land than in the water, so the area around the pond matters as much as the pond itself. Leave a patch of long grass, a log pile in a shady corner and a few flat stones loosely stacked. Frogs will use these to hunt, shelter and hibernate, and newts will tuck themselves into damp crevices from October onwards.

Make sure there is an easy exit. Floating a piece of timber with one end resting on the bank gives any creature that falls in a ladder back out. If your pond sits above ground level, add a roughened ramp on the shaded side. Keep a shallow drinking beach for hedgehogs and birds too — a slab set at a gentle angle means they can drink without falling in.

Resist the urge to introduce spawn or newts from another pond. Movement of amphibians spreads disease, and a healthy pond will be found and colonised naturally within a couple of seasons.

Water quality and seasonal care

Rain-fed ponds are best. Top up with water from a butt rather than the tap, because tap water carries nutrients and traces of chlorine that encourage algae. Avoid fertiliser, slug pellets and weedkiller anywhere near the pond — amphibians have permeable skin and absorb whatever runs off the garden.

Leave the pond alone from late autumn through to early spring. That debris at the bottom is hibernation habitat. If you must thin the plants, do it in late summer and leave any trimmings on the bank for a day or two so that anything caught up in them can crawl back.

Blanketweed in spring is normal and usually settles once plants get going. A bundle of barley straw floated on the surface can help keep it in check without chemicals.

Things that put amphibians off

• Fish — even a few goldfish will eat spawn and tadpoles. Keep fish ponds and wildlife ponds separate.
• Steep, smooth sides with no shallow shelf or exit route.
• Ducks in quantity, which foul the water and trample marginal plants.
• Pumps and filters that pull tadpoles into intakes — if you use one, fit a fine guard.
• Neat, tidy margins. A little untidiness is the single best thing you can offer.

Patience is the final ingredient. A new pond may sit quiet for a season, then one mild February evening you will hear the low, chattering croak of frogs and find clumps of spawn in the shallows. From there, the pond belongs to them.