A compost turner is a gardening tool which is used to turn compost to promote aeration and rapid breakdown of the materials in the compost. Compost turners are a vital tool to have around for composting, as poorly aerated compost will grow unhealthy, breaking down slowly and smelling rather unpleasant. Many gardening supply stores carry compost turners, and it is also possible to improvise with other tools, for people who do not want to buy a specialized compost turner.
In home composting, the goal is to promote bacteria and fungi which will break down food, yard scraps, and other organic material, generating a rich brown to black mass of soil which can be used to enrich the garden. Home compost piles usually harbor bacteria which need air to survive. As a compost pile is started, the bacteria move in and set to work, but as more material is added and the compost is compacted, air stops reaching the core of the compost pile, which means that bacteria cannot work there.
With a compost turner, the compost is churned up so that air penetrates the depths of the compost pile. The turner also loosens the compost again, creating air pockets which will be friendly to bacteria. Compost typically needs to be turned every few weeks, depending on the rate of decomposition in a compost pile, and some people amend their compost with straw when they turn it, using the straw to create additional air pockets for the bacteria.
If compost is not turned, the bacteria will only be able to live on the margins of the pile, leaving materials in the middle undigested. This can promote rot, and an accompanying unpleasant stench, and the objects in the compost pile will not break down. As an alternative to using a compost turner, some people use a compost aerator, a long rod which is driven repeatedly into the compost pile to force air into the center of the pile for the bacteria. Gardeners can also use rotating compost bins, which aerate whenever they are spun.
Shovels, hoes, and sturdy rakes all make great compost turners, and many people have these tools around the garden anyway, making it easy to apply them to compost. It is also possible to obtain a specialized compost turner or aerator. Gardeners who do not want to deal with aerating or turning compost should consider a spinning compost bin, a convenient alternative which is also very easy to use, or a stacked compost rack, which promotes air circulation by holding compost at different levels.