As the last summer flowers fade and the first mists settle, our gardens become vital refuges for wildlife. Hedgehogs are busy fattening up before hibernation, and a well-built house offers them a safe, dry place to sleep. With untreated boards and a handful of dry leaves, you can create a shelter that lasts for years. Here’s how.

Why hedgehogs need a helping hand in autumn

Hedgehog numbers have fallen sharply in the UK, and gardens are now one of their strongholds. By autumn, a hedgehog needs to weigh at least 600g to survive hibernation. It seeks a sheltered, undisturbed spot with a steady temperature. Compost heaps and log piles can work, but they flood or get disturbed. A purpose-built house is reliable and cheap. October and early November are ideal for setting one up.

Choosing the right materials and location

The golden rule is untreated timber. Treated wood contains preservatives that are toxic to hedgehogs. Use 18mm plywood, pine or cedar. Avoid chipboard, MDF, paint or varnish. You will also need galvanised screws, a hinge and roofing felt or slate.

Place the house in a quiet, shaded corner – under a hedge, behind a shed or beside a log pile. Face the entrance away from the prevailing south-westerly wind (so north-east or east) to keep rain out. Raise it on bricks to keep the floor dry, and ensure it sits on bare earth or short grass.

Building the hedgehog house step by step

A simple rectangular box with a tunnel works perfectly. Aim for a floor of 40cm by 40cm and a height of 25cm. Cut untreated timber to these sizes:

• Base: 40cm x 40cm
• Two sides: 40cm x 25cm
• Front and back: 36cm x 25cm
• Roof: 44cm x 44cm (with 5cm overhang)
• Entrance tunnel: 15cm long, 13cm x 13cm square

Screw the base, sides, front and back together. Cut a 13cm x 13cm hole in the front for the tunnel. The tunnel is long enough to stop cats and badgers – 13cm square is too narrow for predators but perfect for hedgehogs. Attach the roof with a hinge and latch so you can clean it. Cover with roofing felt or a slate. Drill small drainage holes and raise on bricks.

Lining the house with dry leaves

Fill loosely with dry autumn leaves – oak, beech, hawthorn or hazel. Avoid sycamore and horse chestnut, which turn to mush. Never use hay (it moulds) or chemically treated straw. A little shredded paper is fine, but leaves are best.

Don’t overfill. Leave a hollow in the centre so the hedgehog can burrow. It will add more bedding itself. Never use treated wood shavings or sawdust from unknown sources. The lining must be dry and chemical-free.

Maintenance and safety checks

Once a hedgehog moves in – usually November to March – do not disturb it. Waking a hibernating hedgehog burns vital energy and can be fatal. Check from a distance for droppings or moved bedding. Clean the house in late October or late March only, using hot water. Never use disinfectants or soap.

Keep the area free of slug pellets, insecticides and rat poison. Ensure pets cannot reach the entrance. Leave a shallow dish of fresh water nearby – never milk or bread.

Encouraging a hedgehog to move in

Leave a wild corner with long grass, a log pile and leaf litter. Avoid tidying up too much in autumn. A feeding station a metre or two away (meat-based dog or cat food and water) will attract hedgehogs, but keep food out of the house. Be patient – it may take a season. Once found, hedgehogs often return. If you see one out in daylight during winter, it is likely in trouble; contact your local wildlife rescue.