We typically teach composting using the example of leaves for carbon (browns) and grass clippings for nitrogen (greens). This is an accurate, easy-to-understand example for most homeowners to follow because leaves and grass clippings are common yard wastes.
In real life, however, an abundance of leaves tend to fall in autumn, when there are few grass clippings available. Grass clippings tend to be bountiful in spring and summer, when few leaves are falling. So, building a hot batch pile out of grass clippings and leaves isn’t as easy to organize as it seemed in compost class. Fortunately, there are solutions to the Too Much Spring Nitrogen vs. Too Much Autumn Carbon dilemma.
Greater Variety of Nitrogen Materials in Autumn
The most obvious answer is to use a wider variety of inputs. When leaves are falling, the weather is usually turning chilly so even more hot coffee is consumed. Many coffee shops discard nitrogen-rich grounds separately from inorganic wastes, and will happily give you as much as you can carry. (Tip: Set them inside an ice chest to protect your car’s trunk in case of leakage.)
Football season conveniently comes in autumn, when spectators’ leftover or spent beer, soda, and sports drinks are likely to become available in larger quantities. If you don’t throw fan parties or drink beer yourself, you may need to be creative in figuring how to get others to donate these wastes to your compost pile.
When you reach the end of November and grass clippings are really scarce, homeowners discard pumpkins they’ve been using as fall lawn decorations. I normally don’t recommend composting food in piles, especially for beginners. In this case, the pumpkins have already been sitting out in your neighborhood for two months. If they’ve attracted mice, the mice are already there and may have gotten their fill of pumpkin. It doesn’t seem to me that the problem is likely to get much worse by transferring the old pumpkins to your compost bin as long as you put at least 10″ of yard waste between the pumpkins and every side of your bin, as well as top and bottom of pile. Cut the pumpkins up into chunks so the decomposers can get directly to the meat without having to go through the waxy surface.
That’s three sources of autumn nitrogen. And, of course, urine from healthy humans is considered an acceptable nitrogen input to home piles as long as it’s deep enough in the pile not to cause odor issues. I’ll let you figure out transport and delivery on your own.
Deficit of Carbon Creates an Odorous Lack
A lack of nitrogen in autumn can slow the decomposition in your pile. That’s irritating. But let’s face it, the real problem comes in spring and summer when you have smelly nitrogen decomposing and can’t find enough carbon to mask the foul odor. Not only is your enjoyment of the outdoors impaired, but probably your relationship with your neighbors as well. A pile of nothing but grass clippings will bring you nothing but stinky trouble. You must have carbons – and you probably do, delivered to your doorstep every morning.
Newspapers, cardboard, and shredded office and school papers are all carbon sources. They don’t have a huge nutrient value due to processing, but they will help mask odors in the pile. They should be shredded and mixed with yard wastes before being added to the pile if possible, so they don’t mat when moistened.
The real solution to this problem is to collect as many leaves as you can find in autumn and save them until you need them. At first it sounds crazy, but you will see the value of saving leaves the first time you have a pile of excess nitrogen.
I used to have a bin made of huge pallets where I put every leaf I could get my hands on. I had enough leaves for ongoing hot piles throughout spring and summer. Lately, I have been collecting bagged leaves to use as insulation. I pile bags of leaves around my compost piles two high and two deep for insulation so I can compost as it gets colder. I also use them to surround my raised beds to insulate my plants from freezing temperatures. They provide insulation during winter.
Once spring arrives, I empty leaves into the pile as they are needed, and tear up the paper bag to deposit into the pile as well.
Next Spring, you’ll understand this dedication to leaf collecting and wish you had participated.
Mary Tynes, Master Composter, www.mastercomposter.com
Image Credit (top left): http://www.flickr.com/photos/quattlebaum/2682956344/
Image Credit (bottom right): http://www.flickr.com/photos/shamanic-shift/274869407/