The boards I used were 15cm wide and 4.8m long. The length actually determined the width of the bins – I simply divided the length of one board by three which gave me three bins each 1.6m wide – wide enough to accommodate my needs (!). My mighty, substantial needs. A board cut in half gave me the depth of the bins: 2.4m. Six boards nailed to the posts made bins 90cm high.You may, as I did, over engineer the fixing of the posts into the ground and use post spikes. These are long spikes that you first hammer into the ground, with a square bracket at the top that holds the posts. BUT they are a pig to use. They invariably twist as they go into the ground and as they have to remain square, this is a real pain. Also it is very hard work to sink them into the ground – I put the bins at the Priory on the site of an old brick road (called, rather charmingly and aptly, The Red Road). Imagine hammering these spikes through brick. Hard work? Yeah, just a bit. So don’t use spikes. Do as I did at the Old Forge and just sink your posts a foot or so into the ground and then back-fill with hardcore and soil. When you nail on your boards and the bins are full, they won’t budge much.
The bins I’ve made for both the Old Forge and the Priory are very big but that is because they have to accommodate a ride-on mower and/or a trailer. Make yours to a size that suits; in my own garden, the bins are 1.5m wide but only 1m deep.
(Sorry this is all pretty dry stuff. Almost done – hang on in there; you can all go outside and play in a minute). I was always going to build two lots of three bins at the Priory and realised that if I spaced them correctly, I could have a seventh bin made out of the gap
between them. Finally, screw or nail a batten to the front edge of each of the posts at the front of the bins (the red piece of wood above) and to that, attach a length of planking equal to the height of the bins.
Here’s a close up of that arrangement with one of the front boards shifted slightly out of position. Gosh, but this is gripping stuff.
You can then cut six planks to slide down the front of each bin. Strictly speaking you don’t need to do this but it does increase the amount of compost each bin will hold without spilling out of the front. Site your bins in the open, not under trees; you want rain to fall on them. Build them on level ground if you can – it’s much easier than building them on a slope. Much, much easier. Do you cover the compost? Hmm. Well, I don’t. Should I? Probably. It would keep in moisture and warmth and keep thistle-down out. Perhaps I’ll cover them next year. Perhaps I won’t. Perhaps I’ll just surprise you. Keep you guessing. On your toes. And that’s it. Easy peasey, lemon-squeezy. If anything’s not clear – please say. Next week I’ll be showing you how to build your very own domestic nuclear reactor. Free energy for life! You’ll need to bring your own uranium fuel rods. And hammer. Please don’t forget.