Microbes, bugs and worms will do the work. No one turns a forest floor where even the fallen trees will compost just fine. However, in your backyard compost where you add lots of kitchen scraps, you will want to make the compost by balancing it with "browns". This fluffy material will provide pockets of air, too. Add similar amounts of nitrogen-rich greens, like your kitchen scraps, to carbon-rich browns such as dry leaves, straw or shredded paper. Add a little old compost or soil to provide a variety of microbes and grit for the worms. Always top off with the browns so that it does not smell. Keep it damp. That’s it! On the other hand, if you are making hot compost, it needs to be aerated to keep the heat-loving bugs (thermophiles) active. Build the pile at one time. If you are using a Speedibin, fill it at least ¾ full. Turn it with a fork or aerating tool about every two or three days until the temperature stops climbing. Monitor it with a compost thermometer if you have one. Or poke in a length of re-bar and feel how hot it gets. We’ve made compost in less than a month this way. Then you can turn out this compost, maybe use it as mulch, and let the final stages of decomposition take their time. Meanwhile, you've made room to start another hot compost pile. We have noticed that problems with composting are more likely to be insufficient water, not insufficient air. (Tumbler composters are solving a non-existent problem, IMHO.) As a lazy gardener, I like to let the worms to the heavy lifting. Check out these tireless worms in our Speedibin even through the winter! They certainly do a better job of aerating than I ever could.
Question: Do I have to turn my compost? Answer: Kitchen and yard waste will compost even if you do not turn it.