One wooden box in a quiet corner of the garden can decide whether a hedgehog survives the winter. Here are the dimensions, materials, illustrated instructions and a maintenance calendar – compiled from WWF Finland, the Finnish Association for Nature Conservation, the British Hedgehog Preservation Society and Naturskyddsföreningen.
The hedgehog is a protected species in Finland. Even so, populations have fallen sharply across Europe – an estimated 16–33% over the last decade – and in 2024 the International Union for Conservation of Nature (IUCN) moved the hedgehog from "Least Concern" to "Near Threatened". The single biggest cause is the loss and fragmentation of habitat in gardens: a tidy, "cleaned up" garden offers nowhere at all to overwinter. Climate change's unstable winter weather – thaws and sudden hard frosts by turns – significantly raises mortality in a hibernating hedgehog if its nest isn't well enough insulated. One well-built, well-placed nest in your garden can be the deciding factor.
Both work. The quick version gets shelter up today; a proper wooden box lasts for years and insulates better through a long, cold winter.
Flip a sturdy plastic storage box or planter (about 40 × 40 cm or bigger) upside down. Cut a 13 × 13 cm door in the edge, fill with dry leaves, cover the box with sheeting and then soil/leaves. Not perfect, but far better than nothing – and a hedgehog will thank you this autumn.
A bottomless nest box of untreated timber, with a tunnel and a removable roof. See the dimensions and step-by-step guide below. Lasts for years and insulates best.
Finnish and Swedish nature organisations recommend a bigger box than in southern Europe, because a long, cold winter needs a thicker insulating layer of dry leaves. The British Hedgehog Preservation Society uses a smaller design of about 40 × 30 × 26 cm, which also works well as a summer day-nest – fine if space or materials are limited, but bigger is better for winter.
Original diagram, Siili-Saari — compiled from WWF Finland, the Finnish Association for Nature Conservation and the British Hedgehog Preservation Society. Not to exact scale.
Fill the box almost to the roof with dry leaves and straw – the hedgehog will arrange the nest to suit itself and may top it up further with extra material left near the entrance. Finally bank soil, turf, grass clippings or brash up and around the box (not in front of the door) – this "insulating jacket" matters more over winter than the box itself. Let snow settle on the roof: it adds insulation, so don't clear it off.
Don't put food or water inside the nest – it disturbs the hedgehog. Place a shallow food/water dish (cat or dog food, no milk) a few metres away from the nest instead.
| When | Task |
|---|---|
| Aug–Sep | Build and place the nest by the end of September at the latest, so a hedgehog has time to find it before frost sets in. |
| Oct–Mar | Leave the nest completely alone. No cleaning, no moving it, no peeking inside – disturbing a protected species' winter nest is also against the law. |
| Apr–May | First clean-out once hibernation has ended, but before the breeding season. Wear gloves (and ideally a mask) – old nest material can carry parasites. |
| Jul–Aug | A light check/clean and fresh filling before the nest is used again for autumn hibernation. |
This guide is compiled from the following organisations' published guidance. The diagram above is Siili-Saari's own, drawn from these sources' dimensions.
Note: build photos are still missing from this page. To be added once Siili-Saari builds its own example, or with our own photos – other organisations' photos are not published on this site without permission.