Why solitary bees need a helping hand

Of the roughly 270 bee species in the UK, only the honeybee and a handful of bumblebees live in colonies. The rest are solitary bees that nest alone. They use hollow plant stems, old beetle holes in dead wood, crumbling mortar and sandy banks. In tidy gardens and flailed hedgerows, these niches vanish. A well-made bee hotel from recycled garden materials can offer safe nesting tunnels, but a badly made one can become a death trap. The good news is that you can build one from stems, logs and untreated timber you already have.

Gathering materials from garden and hedgerow

Late winter and early spring are ideal times to gather and build. Forage responsibly: take only dead, dry material, and never strip living hedgerow plants. You will need:

• Hollow stems: bamboo canes, raspberry and blackberry canes, elder, teasel, fennel, sunflower and cow parsley. Cut into 10–15cm lengths. Keep one end closed by a natural node or plug it with untreated wood.
• Drilled logs: untreated hardwood offcuts such as oak, ash, beech or sycamore. Avoid softwoods that bleed resin. Seasoned logs are best.
• Untreated timber: old drawer sides, heat-treated pallet wood, or fence offcuts. No paint, varnish, wood stain or preservative.
• Container and roof: a wooden box or drawer, floorboard offcuts, and a slate or tile for the roof. Avoid plastic.

Making the nesting tunnels

Solitary bees are fussy about size. Different species use different diameters, so aim for a mix:

• 2–5mm: small species such as yellow-faced bees.
• 6–8mm: red mason bee and many other spring-flying solitary bees.
• 8–10mm: leafcutter bees and some larger species.

For drilled logs, use sharp drill bits. Drill holes 10–15cm deep, slightly longer than the bee's body, but do not drill all the way through. A through-hole lets light in and invites parasites. Drill across the grain if possible. Space holes 15–20mm apart. Clear sawdust and lightly sand the entrance to remove splinters. For stems, cut cleanly with secateurs or a fine saw. Bundle stems tightly so there are no gaps; gaps attract mould and pests. The open ends should face out, and the closed ends should sit at the back.

Building the hotel

Make a simple box from untreated timber. Internal depth should be 15–20cm. The back should be solid, and the roof should overhang by at least 5cm to keep rain off. Leave the front open. Mount the hotel on a wall, fence or shed, 1–2 metres above ground. Face it south or south-east to catch morning warmth. Shelter it from prevailing wind and driving rain. Angle the box very slightly forward so water runs off, but not so much that the tunnels fall out. Pack stems and logs tightly. Put a few drilled logs at the bottom and bundles of stems above. Do not use glue or expanding foam. Keep the whole structure stable so it does not sway.

Siting, seasonal care and hedgerow neighbours

Place the hotel near good forage: flowering hedgerow shrubs, fruit trees, herbs and wildflowers. Red mason bees emerge from March to May, while leafcutter bees fly in summer. Once the hotel is occupied, leave it in place. Moving it can disorient the bees. In autumn, leave the stems and logs alone. In late winter, check for damp or mould. Replace used stems every two years if you can, or add fresh bundles alongside the old ones. Avoid insecticides anywhere near the hotel. When foraging from hedgerows, take only a small amount from any one plant and leave plenty for wildlife. Ladybirds, lacewings and earwigs may also shelter in the hotel. They are part of the garden ecosystem, so let them be.

Common mistakes to avoid

• Plastic tubes or drinking straws: they trap condensation and do not breathe.
• Splintered holes: these can damage bees' wings. Sand entrances gently.
• Holes that are too shallow: less than 10cm produces more male bees and fewer females.
• Painted or treated timber: chemicals can harm bees and their larvae.
• Drilling into living trees: this damages the tree and does not help bees.
• A wobbly hotel: movement disturbs developing larvae.
• Rain ingress: a roof and a slight forward tilt are essential.
• Straw, pine cones or hay: these are not nesting tunnels and may attract pests.

With a little care, a recycled bee hotel becomes a quiet, productive corner of the garden. You will see neat mud plugs in spring and leaf-wrapped tunnels in summer. It costs nothing but time, and it gives solitary bees exactly what they need.