Which Home Composting Bins are Best?
Which Home Composting Bins are Best?
Compost can be made in any container that allows air to flow in and out, that can keep heat and moisture in and cold and rain out. Compost structures can be temporary or moveable, they can be beautiful and permanent. What you choose depends on your needs and personality as well as time, money and DIY skills. Inventive recyclers like to use cast-off dustbins, thrown-away pallets or dumped building materials. But you don’t have to make your own to make good— effective plastic bins are also popular and widely available.
Simple one-bin systems suit most gardeners. Size is the most important factor. You can’t easily make hot compost in anything less than a cubic metre, as you need a reasonable volume to maintain the temperature. On the other hand, an over-large pile can be difficult to keep moist, well aired and evenly warm.
Ease of access is another consideration. If you are turning your compost regularly you need to keep your container fairly low so you can scoop out the compost, or it needs to have a detachable front, or to be easily disassembled. If you can’t get at your compost easily, there’s not much incentive to look after it and you can end up with problems, so it is worth spending a bit of time and thought on your container.
Don’t be put off making a bin because your DIY skills are marginal. Sectional boxes can be built by even fairly incompetent carpenters. Cut twenty 17cm-long blocks of 5cm x 5cm timber and make five separate squares by nailing-15cm x 1m boards to the blocks, leaving a stump on either side. Place the first square on the ground and fill it, then add the next and so on. There will be a gap of approximately 2cm between each section for air to circulate. Fill all five square sections and use a square of carpet as a lid. It is easy to lift off the sections to turn the heap.
Once a coolsystem gets going well you should be able to remove compost from the bottom of a pile while adding raw materials at the top. A bin with solid sides and removable slats at the front can permit continuous supply.
The ‘New Zealand Box’ is a traditional 1.25 m square wooden compost box. Boards slot into the front between two posts so it is easy to add materials and remove compost. Some gardeners use them for hot composting and build them with slatted sides to allow extra aeration. You could build one from offcuts or reclaimed timber salvaged from skips, or haulage pallets. Three pallets wired together make an ideal compost box — just stick a couple of stakes in front to slot boards into.
If you have a large garden and plenty of materials to compost you can have two or preferably three adjoining boxes, or make one large box in two or three sections. Fill one section at a time and leave it to mature slowly while you fill the next one, using the most mature compost. Or if you’re very keen, with lots of waste, you can use three bins for quantities of compost, moving the heaps between the bins.
Some tidy gardeners like to build permanent compost boxes out of bricks, breeze blocks, or even stone. If you do go for permanence, it’s worth trying something else for a year just to make sure you have chosen the best site, and never make a permanent concrete base.
They may not look neat, but straw bales make good compost surrounds, particularly in cool gardens where they provide insulation. The optimum size heap uses thirteen bales, stacked three high on three sides with overlapping ends. You can pull more across to close up the front, and cover the heap with a sheet of carpet or corrugated iron. Re-use the straw in future batches of compost.
Cages and Metal Bins
These bins are great for leafmould and can make adequateif you insulate them well by wrapping carpet around the outside or cardboard inside, and cover the top with thick carpet. Their benefits are economy, ease of construction and flexiblity — join the mesh with wire clips and they can be dismantled in a trice so you can turn your compost or move the bin to start a new compost pile in another part of the garden. The main minus is the need for insulation, and you need to watch aeration carefully.
Dustbins and metal drums
An old metal dustbin can be transformed into a useful cool composting container. It is not large enough to make hot compost successfully unless you are prepared to turn the compost every few days, and even then success is not guaranteed. Drill holes in the sides, and a couple in the lid, for aeration, and site somewhere sheltered as the bin won’t maintain heat effectively in cold weather. It is best if the bottom is pushed out so the bin stands straight ontoand earthworms have easy access.
Old oil drums have slightly larger capacity to make more useful containers, but be very careful to clean them thoroughly. Take out the base and stand your drum on double rows of bricks on the ground. If possible drill holes in the sides as for a dustbin. If the metal is too hard insert a tube of coiled wire or a section of 10cm perforated pipe down the centre of the drum to aid aeration, and always start your pile with at least 15cm brushwood. The central pipe should act as a natural chimney, pulling air up from beneath the heap. It is tricky to turn a metal drum, so build your compost in layers, inserting tubes for extra aeration.
Plastic Bins and Tumblers
There is a wide variety of plastic compost containers on the market. Their volume is usually the limiting factor. Always purchase the biggest container you can — it needs to be over 250 litres for effective composting. Anything smaller will have problems keeping heat in. For the same reason try to find a container with reasonably thick walls and a tight-fitting lid. If it has a base, make sure it has some holes for drainage, but it shouldn’t need ventilation holes in the walls if you mix the right materials. You need to take just as much care in siting and feeding a compost container as any compost heap or pile.
Containers shaped like inverted cones work well because any condensed moisture trickles down the sides, allowing the centre to heat up well without cooling, but keeping moisture in the pile. Square and barrel shaped containers are easy for access, for turning the compost or for removing it.
Some bins have removable sides for accessing finished compost, others have flaps or drawers at the base but these need to be substantial to have any value. It is usually more practical to remove the bin altogether, and remix uncomposted material to start a new batch.
Probably the most foolproof composting devices are compost tumblers, barrel shaped plastic containers mounted on an axle so you can turn the compost easily by tumbling the composter over. Daily turning means compost ingredients heat up well and keep well aerated for swift decomposition, so you can make finished compost in less than a month: fill the bin all at once if possible, mixing shredded ingredients together well, and when it is full turn it daily for two weeks. Then corn post can be removed and the bin refilled. You can use this compost fresh on your garden but it is best if it is left to mature under cover for a month or so.