A compost bin is an essential piece of equipment for food growing gardeners. Taking up a comparatively small amount of space just one bin can be highly productive and help us to nourish our soil on a regular basis. First and foremost a compost bin gives us an easy method of recycling our vegetable scraps, trimmings and weed-free garden rubbish. The reward for regular bin filling should, over time, be a mound of nutrient rich compost filled to the brim with beneficial insects, fungi, microscopic organisms as well as earthworms that will all help to improve the consistency and fertility of our garden soils.
Compost bins are generally all around the same size – give or take a few inches. If you pace out a square on the ground that is about a stride by a stride then imagine this base square coming up to about waist height then you have the approximate dimensions of a garden compost bin - easy enough to tuck into a corner of your garden for some ultra-efficient recycling. The general rule with compost bins is that, once filled with vegetative material, they take between 6 months and a year to fully rot down their contents into useful compost. For this reason many gardeners have two bins - and sometimes three if there is adequate space and a ready supply of compostable material. With two or more bins you can be filling one up whilst using rotted compost from another to add to your garden.
There are simple ways of making compost bins - from the most basic pile of organic material with a tarpaulin covering it to simple structures comprising chicken wire stretched around four waratahs. Then there are home made DIY marvels with slats, hinged lids and warm compost covers to keep in the heat. Whatever you technical and aesthetic inclination are, the basic principle is to create a receptacle that holds the heap together as the microorganisms go to work. It helps to have a lid or some sort of cover to prevent rain soaking the heap and slowing decomposition. Ideally your bin should be strong enough for you to be able to work the compost inside it with a fork or spade without the whole thing falling apart. If you are making your own out of timber try and use untreated macrocarpa which can be used to make a whole range of garden structures. Needless to say, garden centres have a bewildering range of recycled plastic bins but these tend to be a bit flimsy and we would recommend a traditional wooden bin over them any day.
Compost bins work best in a sunny spot where their contents are given extra warmth from the sun to speed the composting process. They only really smell if the composting process is for some reason not working efficiently but they do attract rats and mice so you might want to position them away from the house. Access is an important consideration, you may want to get a wheelbarrow up to your bin to fill or empty it. To allow micro-organisms to enter a compost heap it is best if they are placed on bare earth rather than on concrete or any hard-standing.