Tuesday, February 28, 2017

Lessons Learned from Composting Experiences

Jack and I have composted the fallen leaves at our house since we moved here about 5 years ago. When we first started composting our leaves, I read a lot about the "rules" of composting. The rules say that you need a 30:1 ratio of "browns" (leaves and other high-carbon materials) to "greens" (grass, garden waste, and other high-nitrogen materials). If you have just leaves and grass, a pile composed of 2 parts leaves to 1 part grass clippings is ideal. But when, like us,  you have a mix of vegetable scraps and coffee grounds as your sources of nitrogen, calculating the correct ratio becomes too challenging. What are the consequences of getting the ratio wrong? Too much nitrogen and the pile can get too hot and become smelly (or so, I've read. We've never had this experience.) Too little and the pile won't heat up and is slow to decompose. We never had enough greens to reach the suggested carbon to nitrogen ratio so in the past we used bagged ammonium nitrate (34-0-0) fertilizer to make up for the lack of nitrogen. 

Other composting rules say that the pile must be kept moist, but not too wet, and that you must turn the pile to maintain good oxygen level while it is in the hot composting phase. Also, the materials in the pile (in particular, leaves) should be shredded or chopped to make the particles small, but not so small that airflow is inhibited. I never realized that composting was so complicated!! 

The first year we composted, we tried to do everything just right. We calculated carbon-to-nitrogen ratios (or tried to). We chopped and shredded. We moistened and turned. And we made compost, but it took a full year. 

At the other extreme in composting practices are those folks who don't observe composting rules; they just pile stuff up and wait. Over the years, our technique has moved more toward this end of the continuum. Experience has taught us that small particle size is important if we want our fall leaves to be usable compost by the next year. Jack now runs over the leaves 3-4 times with the lawnmower before we transfer them to the compost pile.  Moisture has proven to be important, too, and we water the leaves down as we build the pile so that the pile gets wet throughout. We stopped using chemical fertilizer as a nitrogen source (just our coffee grounds and vegetable and fruit waste), and it hasn't seemed to make a lot of difference in the heat of the pile. In fact, this thermometer is in a pile that was built with nothing but leaves and a few vegetable discards, and the temperature in the pile was 130 degrees.

So we've given up on obsessing about our compost pile and it seems to be doing just fine. These days, there are too many other important environmental (and other) issues to be concerned about!

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