DIY Insect Hotel Windowbox

Invite wildlife into your yard by building this windowbox to encourage habitation.

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by Flickr/Alan Tough

Big Ideas for Small Spaces: Creative Ideas and 30 Projects for Balconies, Roof Gardens, Windowsills and Terraces (Firefly Books, 2017), by Kay Maguire and Tony Woods, introduce new and exciting ways to spruce up small spaces in outdoor areas. Maguire and Woods provide step by step instructions with photos for projects that make it easy for readers to follow. Readers will also find plant and flower suggestions that would be best for each unique space. The following excerpt is from Section 4: “The Projects-Pots and Planters.”

The importance of gardens, however small, as habitats for wildlife is increasingly recognized, and with this project everyone can do their bit. And it’s not just the birds and the bees that benefit. You also get to enjoy the colour and scent of flowers and foliage while you watch the wildlife come and go.

Our windowbox had both a nesting box and an insect hotel – a section filled with dead wood, bamboo canes, straw, and bits of stone and old tiles, which will provide crevices and nooks for insects to shelter and breed in.

The hole for the nesting box can be made with a circle bit or a wide drill bit. The hole should be 25-32mm (1-11⁄4in) in diameter, but its exact size will dictate the birds that use the nesting box: for example, a 25mm (1in) hole will attract blue, coal, and marsh tits; a 28mm (11⁄10in) one is suitable for great tits; and a 32mm (11⁄4in) hole will draw house sparrows, tree sparrows, and nuthatches.

A nesting box is most likely to be used if your window ledge is high up, rather than on the ground floor where people coming and going will discourage bird visits. Therefore, if your ledge is near ground level, omit the nesting box and extend your windowbox’s planting areas or the size of the insect hotel.

During construction, line each planter with plastic to help preserve the wood, to prevent preservatives leaching into the potting compost, and to keep moisture in the soil. A soil-based compost is heavier than a multipurpose one and will retain water and nutrients for longer as well as increasing stability. To ensure the windowbox is securely positioned, use small, galvanized, L-shaped brackets to attach it to the ledge.

window with a wooden box on the sill outside with lavender and corn flowers planted in it


  • Tape measure and pencil
  • Lengths of pressure-treated timber, 145 × 20mm (53⁄4 × 3⁄4in)
  • Wood saw
  • Drill with circle bit or wide wood bits of 25mm (1in), 28mm (11⁄10in), or 32mm (11⁄4in), and self-tapping screws
  • Twigs, lengths of bamboo cane, stones, pieces of tile or terra-cotta pot
  • Old plastic potting compost bag, for lining the planting spaces
  • Scissors and secateurs (pruning shears)
  • Staple gun
  • Soil-based potting compost
  • Topdressing, e.g. grit
  • Galvanized, L-shaped brackets
  • PLANTS: Insect-friendly ones, e.g. catmint, cornflower, geranium, Jacob’s ladder, lavender, salvia, thyme, yarrow


Our wildlife windowbox was 84 × 18cm (34 × 7in) so we needed:

  • 3 × 84cm (34in) lengths of pressure-treated timber, 145 × 20mm (53⁄4 × 3⁄4in)
  • 5 × 14cm (51⁄2in) lengths of pressure-treated timber, 145 × 20mm (53⁄4 × 3⁄4in); two of these pieces were for the ends while the other three were for internal supports
  • 1 × 23cm (9in) length of pressure-treated timber, 145 × 20mm (53⁄4 × 3⁄4in), for the nesting box roof


1. Calculate the size of your windowbox by measuring the window ledge. Mark and cut your pieces of wood to the appropriate sizes (see the key, above, for the timber sizes that we used for this project).

man standing at an open window using a measuring tape across it

man using a pencil to mark on a wooden board along a measuring tape

2. Attach the two end pieces to the base plank for the windowbox, using the drill and self-tapping screws.

3. Use the pencil to mark on the base plank where the three internal supports for the nesting box and insect hotel are to go. Screw these supports to the base.

4. On the front plank, mark where the entrance hole for the nesting box and the opening for the insect hotel are to go. Use the drill to make a pilot hole for the nesting box entrance, then fit the wide drill bit and enlarge the hole. Cut out the hotel opening with a saw.

5. Screw the front plank of the windowbox onto the base one and then screw on the back plank.

man using a drill on a cut portion of a wooden window box

6. Fill the insect hotel with the twigs and stones etc. Screw the roof of the nesting box in place.

man cutting twigs to fit inside a wooden box with hand trimmer

7. Line each planting space with plastic, attaching it to the windowbox with the staple gun. Then cut holes in each liner for drainage.

man with both hands holding a pile of soil over a wooden box lined with black plastic sheet

8. Fill with potting compost and plant up with your chosen insect-friendly plants. Topdress with grit. Use the L-shaped brackets to fix the windowbox to the window ledge.

man placing potted lavender in to lined window box


The best plants to attract wildlife, particularly pollinating insects such as butterflies, bees, and hoverflies, are those that have flowers providing easy access to pollen. Avoid flowers that have double or multipetals. Don’t worry about using only native plants – insects aren’t fussy and will happily buzz around non-native plants as long as they are full of pollen and nectar.

Published by Firefly Books Ltd. 2017

Text copyright @ 2017 The Royal Horticultural Society