Saturday, October 11, 2008

I'll Have the Venti Compost Tea, Cream, No Sugar

When it comes to composting, my spirit has always been willing, but my body (and mind) have always been weak. For starters, what literature I have read on the subject always begins by boring me and ends by offering intimidating formulas (30 parts "brown" material such as leaves to 1 part "green" material such as food scraps). Seeing as I have a ready supply of food scraps and, until recently, no dead leaves, I didn't often feel inspired by my reading.

Cut to Friday. Clifford, director of the local Montessori school, brought down an old friend of his who is a master composter from New York state. Adam-the-compost-master is a wiry, energetic man who came equipped with a ready willingness to stick his arm up to his elbow into piles of decomposing horse poop. Unlike my books, Adam is a pragmatic composter and a fan of simple explanations. Adam toured our two on-farm composting sites (both sorely in need of remedial attention) and helped us design a system for the future that will allow our CSA members to participate, offer an educational model, and give us rich black compost quickly without the wretched odor of anaerobic bacteria at an all-you-can-eat buffet.

I was so inspired by his advice that I am overhauling our intern house compost pile (lately tending toward the "dump and run" variety due to stink factor) and offering his suggestions for a simple home system in hopes that you, too, can participate in the transmogrification of food scraps into fertilizer.

The Ethics of Compost

Before you roll up your sleeves and pinch your nose, let me first explain why composting is so beneficial. I've often heard that decomposing matter in landfills is responsible for the release of noxious quantities of Carbon Dioxide and Methane, but I've never understood why home composting would be any different and better. I'm still breaking those food scraps down, right? So won't those gases be released anyway? The answer to that is a qualified yes; while the process of making compost will indeed lead to the release of carbon sequestered in plant matter, it will not include the attendant carbon footprint of landfill transportation. Perhaps surprisingly, it is this process of moving your trash from point A (your house) to point B (the dump) that accounts for much of the worst emissions of waste management. Consider, the carbon in your food scraps is part of the natural carbon cycle--it was in the air, got taken up by the plants, and is now re-released: zero sum. The carbon being burned in fossil fuels for transportation was sequestered long ago, and had not been a part of the atmospheric balance for several millenia. When we add it to the air, we change the present day balance of the atmosphere.

Making your own compost at home fulfills the first two (often neglected) of the three Rs of environmental stewardship, Reduce and Reuse. Besides eliminating of all of that extra food waste, making compost creates a valuable soil amendment. Good compost provides soil with organic matter for tilth--something our dense, cloddy Georgia clay desperately needs--and with beneficial microorganisms (the agents of the decomposition process) which encourage a healthy ecosystem for plant roots.

Essentials of Composting

A healthy compost pile consists of four elements: water, oxygen, nitrogen, and carbon. Simply put, nitrogenous material is anything "green" or "fresh"--your food scraps, animal manure*, or green debris from yardwork, for example. Carboniferous materials are the "browns" of a good compost pile: dry scraps such as fall leaves, straw, sticks, shredded newspaper, or other plant matter that is good and dead. If you are building a home compost pile, you will probably want to fashion some sort of receptacle, so that your compost area is more of a large bin than a pile. The rules of compost bin construction are lose, use what you have on hand but aim for something close to 3' by 3' by 3'. One model that I would like to try is constructed by stacking straw bales for walls and making your compost in the middle. The straw walls will gradually incorporate into your compost. However, many other designs will work equally well.

Sticks should form the bottom layer of your pile in order to keep your pile aerated. Your goal is to encourage aerobic (oxygen-using) bacteria, which work quickly and at higher temperatures without bad smells. If your compost pile brings to mind words like "rotting" and "putrescence", you've cultivated a colony of anaerobic bacteria. Anaerobic bacteria are less than ideal for more than just their stench--the lower temperatures at which they work will take longer to form finished compost and will not be hot enough to break down the protein in meat or dairy products.

But wait, aren't you not supposed to add meat or dairy to compost? As it turns out, that depends. Many people avoid adding meat and dairy to compost piles because of the risk of encouraging scavengers, but if you establish your pile properly, there is no reason why your compost pile has to remain vegan. If you are worried that your compost pile may not reach the temperatures necessary to break down animal products, just leave them out. If you want go all out, however, consider animal products like meat, dairy, or feathers as "green" material.
As a general rule, other approved "Green" compost inputs include:
  • Vegetable scraps
  • Eggshells
  • Coffee grounds
  • Tea bags
  • Citrus rinds
  • Grass clippings
  • Animal manure (the nitrogen to carbon ratio of animal waste will vary depending on the animal. If this is a regular addition to your compost pile, it may be worth checking to see where your animal falls on the nitrogen scale)
  • Small, fresh garden clippings
Some suggestions for "Browns" are:
  • Dried leaves
  • Bark, wood ashes
  • Shredded newspaper or white printer paper (none of the glossy stuff)
  • Wood chips
  • Straw
Ok, so what are your ratios then, and how do you get this pile going? Remember these principles: more air than water, more carbon than nitrogen. Also, bear in mind that "green" material already contains a great deal of water in its cells, so you probably don't have to soak your pile unless you are experiencing a drought or you are overloading your pile with carbon. Completely cover your base layer of sticks with a layer of "browns;" pile your browns up a bit more on the sides so that it forms a bowl shape. Now add your "greens" as an even layer. Finally, cover your greens with another layer of browns so that no food scraps are showing. This final covering layer serves several purposes. From a strictly aesthetic perspective, a layer of browns is far more attractive than exposed decomposing veggies or animal manure. Additionally, it keeps your carbon to nitrogen ratios more more appropriately balanced. If you are composting something especially much larger than two fists, consider chopping it in halves or quarters to expose more surface area and speed decomposition up a bit. The same principle goes for large woody additions: break them into sticks or run them through a chipper, rather than just chucking a yule log on top of the pile and crossing your fingers.

Your compost is finished and ready to apply to your garden when the original contents are no longer discernible, having morphed into something crumbly, black, and wonderful smelling. Depending on your climate and how intensively you monitor your pile, this could happen in as little as a matter of weeks, though 8-12 months is probably a more accurate time frame.

Fall is the ideal time of year to begin a home composting operation, as nature is showering you with all the brown material you could ever want: leaves. Rather than sending your leaves to the city dump, set aside a pretty, sunny Saturday to stockpile leaves for the next year's composting. Bag the dry leaves and store them somewhere out of the way (the rafters of the garage? In a garden shed?), leaving one bag handy and somewhere near your compost pile. Saving your leaves will not take significantly more effort than you'll already expend raking and bagging and shipping them off, and it will make future composting infinitely more effective and simple.

*This probably goes without saying, but limit yourself to animal manure. While it is possible to make so called "humanure," its applications are limited. It is generally inadvisable to use even a well-cured batch on any soil that will touch the food that it grows. So if you have a composting toilet and an orchard, go ahead, make humanure and fertilize those trees! If you're planning on growing veggies, however, limit your compost additions to animals and vegetables.

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