Whatever the size of your garden, there's a compost bin to suit. If you have a small lawn surrounded by perennial shrubs, you won't produce much garden rubbish, but you will have to deal with lawn mowings, prune the shrubs and produce raw fruit and veg scraps from the kitchen. Herbaceous prunings blend beautifully with sappier grass and kitchen waste, so they can be transformed into valuable compost.
When choosing a compost bin, select one that looks unobtrusive and blends in with shrubs and climbers. Green and pale brown bins are better than black for this. It's also best to put your composter in a sunny spot: the hotter the compostables, the faster they'll rot. If you stick your bin in a shady place or behind a shed for example, you will still get compost, but it will take several years. As a general rule, compost bins should be placed on soil to attract soil organisms and compost worms, but a few units have solid stands which mean they can be placed on slabs or concrete.
The larger the compost bin, the better. My compost bays measure 1.5 cubic metres and are big enough to keep working through the winter, but a smaller unit, holding as little as 200 litres, may be fine for you. Any smaller than that and it won't generate enough heat to do the business. An oakwood composter, made from resin with a wood-effect finish and 70cm tall, might appeal if you have a tiny space, but with a capacity of 120 litres it is useless. It's a false economy to invest £50 in such bins.
Having rejected bins that look like oak barrels, don't be tempted by the beehive variety. Prices for wood composters of this kind range from £50-£150. Granted, they are small and look natural but they are a waste of money. Square wooden sides are placed one on top of another, with air slats round the perimeter, and as a result far too much heat escapes and the compost heap is always cool.
While these are the worst compost bins I've come across, plenty others are poorly designed. Manufacturers mistakenly believe air will enter through holes and slats round the perimeter and somehow circulate through the heap, but the air moves no further than the edges. Compost exposed to air at the perimeter simply dries out, so the micro-organisms stop working. In other square plastic units, the sides are joined by plastic rods. Again, the compost dries out at these corners, as it does round the bottom of a bin sitting on a plastic base. Scottish temperatures are pretty low, so you need to keep your compost bins snug and moist with solid sides.
If you don't have space for a compost bin, you'll probably have planters and window boxes that need compost. The best alternative for processing kitchen scraps and small amounts of vegetation is a wormery. Worm compost – wormcast – is much richer than ordinary compost and should be treated as a fertiliser. Because commercial compost in your container may be past its best by the end of June, container-grown plants benefit from a top dressing of wormcast.
There are two designs for wormeries: the traditional one looks like a plastic rubbish bin with a tap at the bottom. Most of the space is the working area for worms, with a lower sump for collecting surplus liquid which is drained off periodically. As the worms process the fruit and veg, they work towards the top, leaving the wormcast underneath. The system works well until you want to excavate the compost. You need to remove the worms and their food, together with the top 15-20cm of wormcast, where there are lots of wrigglers. When removing the rest of the compost you have to check it over for more worms.
The second, and easier, type of wormery consists of three baskets or trays with a sump at the base. After the worms have filled the first basket, a second is put on top, and when it's full, a third is placed on it. By that time, all the worms will have left the bottom basket, so you simply remove and use it for your containers.
For more on running a wormery and using kitchen scraps to revitalise spent commercial compost, visit my website – www.askorganic.co.uk.
