Our Big Bug House – Final part

In part 2 of this series, we looked at building the pallet stack and putting a strong water tight roof on the bug house. If you missed the previous installments you can find part 1 here and part 2 here.

In this final part, we will look at modifying the roof to turn it into a green roof and finishing all the habitats.

To attract in more insects, we decided to add a green roof as the finishing touch to the structure.

The plan is to plant this up with bee and insect attracting plants and wild flowers. Over time, it’s hoped this will naturalise into a perpetual green roof populated with plants that like the semi-arid conditions.

Constructing the green roof
The first stage was to add deep end boards to the bottom of the roof, screwing these into the rafters for a really secure fit. These boards support most of the weight of the wet soil and need to be really robust.

Next, we needed matching deep boards for the sides of the green roof. These were cut to match the angles so that they butted neatly at the apex and were attached into the OSB through the roofing felt. We used quite long screw to achieve this as we were screwing into relatively thin boards and needed as much support as possible to stop the weight of the soil pulling the boards off.

One of the issues with converting a pitched roof into a green roof is retaining the soil against its natural inclination to slide off especially when it gets wet and heavy.  To help prevent this we incorporated baffle boards made from treated battening (to slow down the rot) and help to make sure the soil at the top stays put until the plants have established. Once established the matted plant roots will help stabilise the soil, in effect turning it into a wild flower turf.

The battening was deliberately chosen to be shallower than the depth of the side boards to allow some space underneath for water drainage and space on top for some soil depth. This was positioned a third down from the apex and centred on the wall depth. Once we added the soil, the battening was not visible.

The roof was filled with home-made compost from our home compost bins, that turn grass clippings and house hold organic waste into excellent useable compost.

Finally, we added chicken wire to offer some protection to the soil from squirrels and birds, and to help hold it in place until all the plant roots establish.

Planting the green roof
We planted the roof with a mixture of sedums, Nasturtiums, and other wild flowers seeds, specifically chosen to attract pollinators.  Hopefully, these plants will grow into a luscious green roof that will attract insects.

Making the insect habitats
The objective of the individual bug habitats is to provide shelter and security for the future inhabitants, whilst offering a wide range of environments to attract a diverse collection of beneficial insects. In simple terms this means providing loads of different nooks and crannies that are protected from wind and rain.

Outside of the straw used to insulate the main structure of the bug house, we populated the sides with a variety of materials including:

• Bricks with holes
• Old roof tiles
• Bamboo and cane sections
• Cut-off plastic bottles stuffed with twigs, straw, pine cones or a mixture of all three
• Moss
• Chunks of punky/rotting wood
• Toilet rolls and other cardboard tubes stuffed with twigs, moss, and straw

In the remainder of this blog post, we will look at the construction of some of these mini habitats using a range of recycled and natural materials.

When cutting up plastic bottles, we used a variety of techniques – sometimes just cutting the top of the bottle off but also cutting the top and bottom off to make a big tube to hold straw or twigs.

Please be cautious using sharp tools to cut up plastic bottles!

If you leave the bottom on the bottle, make sure you cut some holes in the sides to provide ventilation and alternative entrances/exits for the insects.

We had some old peanut and fat ball feeders that had fallen foul of the local squirrel population; we used these as a convenient way to hold bundles of small twigs and moss.

Cardboard is also an excellent choice for bug habitats. A sheet of corrugated cardboard tightly rolled and tied with string to stop it springing open provides lots of tiny tubes for bugs to hide out in. Better yet, rolling it up Swiss roll style with a layer of straw provides two environments for the price of one.

Toilet roll tubes are a convenient way of housing a number of bug friendly loose materials.

Our bug house project is nearly finished now. There are still a few spaces in the side walls that need to be filled up when we find just the right materials. We are also considering drilling a range of holes in the corner blocks as further solitary bee habitats. Both of these improvements will happen over time as the bug house settles into the general garden scape.

I hope this series of tutorial blogs has given you some inspiration to incorporate an insect friendly habitat into your garden no matter how big or small. Remember to send us any photos of habitats you create and the things that come to stay.