Garden lighting

Garden lighting has three purposes: to make paths and steps safe after dark, to deter intruders, and to extend the use of a terrace or show off planting. A little light, carefully placed and switched off when not needed, does all three better than a flood of brightness.

Types of lighting

• Solar lights need no wiring and can be placed anywhere that gets direct sun. In a British winter they give a weak light for a short time, so they suit decoration more than safety.
• Low-voltage systems run at 12 or 24 volts from a transformer plugged in indoors or in a weatherproof housing. The cable is safe to handle and can be laid by a householder.
• Mains lighting, at 230 volts, is needed for powerful fittings and long runs. It requires armoured cable, buried at a safe depth or fixed to walls, and protection by a residual current device.

LED lamps are standard for all three. Warm white light, of around 2,700 to 3,000 kelvin, is more comfortable to the eye and less disruptive to wildlife than cool white or blue-tinged light.

Electrical safety

Outdoor fittings carry an IP rating showing their resistance to dust and water. IP44 is the minimum for a sheltered position, IP65 for an exposed one, and IP67 or IP68 for fittings set in the ground or in a pond. New mains circuits in a garden must comply with the Building Regulations in England and Wales and the building standards in Scotland, and are a job for a registered electrician, who can certify the work.

Where to put lights

• Paths and steps: low fittings that throw light downwards onto the surface, placed to show changes of level.
• Doors: a shielded light beside or above the door, bright enough to find a keyhole and see a caller.
• Seating areas: soft, indirect light from wall fittings, lanterns or strings of festoon lights.
• Planting and features: a single spotlight on a tree, wall or sculpture has more effect than many lights of equal strength.

Security lighting

A light triggered by a movement sensor draws attention to anyone approaching and uses little electricity. The sensor is set so that it is not tripped by passers-by or animals, and the lamp is angled downwards so that it lights the ground within the property. Very bright floodlights create glare and deep shadows, which make it harder, not easier, to see an intruder.

Neighbours and the law

Light shining into a neighbour's windows is a common cause of complaints. In England and Wales, artificial light from premises can be a statutory nuisance, and a council can require the owner to deal with it. Fittings are aimed down, shielded at the sides, and fitted with timers or sensors.

Wildlife and dark skies

Artificial light disturbs bats, moths, hedgehogs, glow-worms and nesting birds, and adds to the sky glow that hides the stars. All British bats and their roosts are protected by law, and lighting a roost entrance or a regular flight path can cause bats to abandon it. Good practice is to:

• light only what needs lighting, at the lowest brightness that does the job;
• keep light off trees, hedges, ponds and eaves;
• use warm-coloured lamps;
• switch lights off when the garden is not in use.

Other ways of helping garden wildlife are described under gardening for wildlife.