Green Hive Roof mk.II

When I first set up my hives I had the intention of giving them green roofs. I posted a blog about the green roof on Hive1 back in June 2011. It looked good, I'm pretty sure it insulated the hive below nicely, was aesthetically pleasing, helped my hive look a little less obvious to bee paranoid neighbours and even gave the hive proper a little more shelter from the rain. However it was heavy, especially after a rainfall. My solution was to replace the large box with two smaller ones. I was initially considering using aluminium as it's light weight and fairly strong. The two problemns there were I havn't got a clue who could make the items from aluminium and as someone pointed out on a BBKA forum plants don't fare too well in aluminium containers -possibly to do with heat and cold I guess.

Stage one. Not quite done yet.

I opted for a material I've used a little bit before and know where to source. Wood. Specifically gravel board, a treated peice of wood meant to go at the bottom of a wooden fence to protect the fence from the damp ground. I still don't have a decent work surface so once again I got out the mini vices and used a double hive stand weighted down with breezeblocks and a cat.

Stabilise wobbly worksurfaces with breezeblocks and cats as required.

With my still worryingly unstable worksurface I cut the boards to size. My plan was to have three sides of the box hanging over the edge of the metal roof skin and somehow magically join them together once the boxes were in place then unconnect them when I needed to remove them so I could lift of half a green roof at a time.

Testing the fit.

As you can see I used mortise and tenon joins on the corners and a handfull of nails to hold them together. What you can't see is I also used some wood glue on the joints and to hold the pieces together as they dried I used a few staples too. With my prototype green roof it had orignially had a solid marine ply floor but I quickly discovered it was too heavy and cut out most of the floor to leave a frame around the edge to support a two layer lightweight plastic floor. I decided to do the same thing with these to help keep the weight down. I figured I could just use one layer of correx on these as they're so much smaller too. Satisfied with the fit on the hives on the roofs I added a shelf along the long side of each box held in place with yet more glue and nails. Next step was painting the boxes to match the hives. I decided to cut a corner at this point and poured a few litres of shed and fence paint into a bucket then dipped the submerged box ends in using a brush to work the paint across the long sides that hadn't been submerged. It worked okay giving me a pretty good coat of paint. It was also incredibly messy and took days to dry. As the wood was already treated the paint was just an aesthetic touch really.

Green Roof boxes. They're now green.

On the shelves I put a single layer of correx board with the internal walls running the short distance across the gap for support. Correx is the type of plastic FOR SALE and SOLD signs are made of. You can buy the stuff, but if you're lucky you can sometimes find it in the street or in a skip. The black plastic liner was just an offcut of pond liner. I folded the liner into place and used brass drawing pins to secure it. Once they're filled with the growing medium and the plants the contents will hold the liner in place so I'm not too concerned about the pins falling out later in their lives.

I then had to give a little thought to how I was going to joing the boxes to keet them in place. In the end I got some hasps from B&Q, they were the priciest part of the project and I needed one per box. I glued them into place then used the supplied screws to secure them properly. There was nothing to secure the hasps so I just drop a nail into each which seems to work adequately.

Green Hive Roofs Mk.II

The last stage was to add the growing medium and some plants. Once again I opted for mostly perlite as it's lighter than soil, and planted a mixture of sedums, some rockery plants and a few other things I felt might survive in the green roof boxes -over the course of a year they'll probably experience flood and drought conditions. I also transplanted all the plants from the original roof garden into these. It's not really the best time of year for plants to be getting used to a new container but I figure nature will take care of it and whilst some of the plants will quite probably die back others should survive and grow to fill the gaps left. They look nice enough, as the perlite settled I added some vermiculite to the top. Regarding further development I may at some point think about adding a mechanism to allow running off excess rain water, but for now I shall wait and see how they fare.