In the traditional method of making a compost heap, you build alternate layers (2 to 4 inches thick is ideal) of nitrogen-rich (”green”) materials such as manure, grass clippings and kitchen scraps and carbon-rich (”brown”) materials such as twigs, dried leaves and paper.
One traditional layering method calls for first making a 6-inch-deep bed of materials like leaves, grass and weeds. You then top that with a 2-inch layer of manure, and then sprinkle a bit of soil over it all. You keep building the pile until it’s at least 4 feet deep, and water it just enough to moisten everything.
After about six weeks, you turn the pile, then turn it again in 12 weeks. In four to six months, you’ll have usable compost.
Layering makes it easy to see how much of each material you have, and helps keep ingredients in the proper proportion. Generally, a 50-50 mix of carbon-rich and nitrogen-rich materials is considered about right, though that can vary according to how you build the heap, how fast you want it to break down, and what you have on hand.
On the other hand, layering requires more work. And if you don’t have enough materials to build your layers, you have to start by layering the ingredients elsewhere before transferring them to the compost heap.
The layering method produces prime compost and is the technique used in Rod Turner’s excellent e-book on composting, The World’s Best Compost. The difference is that Turner builds the pile in such a way that you don’t have to turn the heap. That saves a lot of time and back-breaking labor.
These days, most gardeners belong to the mix-it-all-up school of composting. You toss together the green and brown materials, toss or turn them occasionally, and let everything decompose. After all, the reasoning goes, you’re going to mix everything up when you turn the pile, so why not mix it up to start with? This is the recommended way to add ingredients to most of the compost bins and tumblers on the market.
The drawback to the mix-it-all-up approach is that without the visual yardstick provided by layers, it’s harder to figure out whether you’re using the proper proportions of green to brown ingredients. If you use too much nitrogen-rich material, the heap will decompose rapidly and give off nitrogen, making it smell and putting greenhouse gases into the air. Add too many carbon-rich ingredients, and the pile will decompose too slowly. If you add carbon-heavy compost to the garden, it can actually steal nitrogen from the plants.
Mostly, whether or not you layer the compost heap comes down to preference. Both methods have their boosters and critics. Try both methods and see which works better for you and your garden.
