Notes from Windward: #69

Hot Compost

George writes:

     Composting is applied magic. You take a bunch of weeds, goat poop mixed with matted down straw, kitchen scraps and assorted other detritus, pile it up just right, add water, stir occasionally and in a couple of weeks you end up with rich, dark brown humus that can be added to soil to enrich it or used as a fertilizing mulch. It could be argued that composting is the basis of organic agriculture -- it builds soil, enables it to hold water long enough for plant roots to use it at their own pace, and provides a suitable environment for the worms and microorganisms that make healthy soil a dynamic living system.

     Composting does take some doing though. Too often compost piles end up as smelly piles of rotting vegetable matter or as dry piles of grasses and sticks that don't do anybody any good. They key is mixing enough brown matter (dead plant parts, wood chips, and other high carbon materials) with enough green matter (living plant parts, manure, coffee grounds and other high nitrogen materials), and keeping the pile moist but not soggy in order to provide a suitable environment for thermophilic bacteria to practice their magic and get to all of the organic matter in the pile.


     The challenges here at Windward as far as developing a useful composting system are twofold -- water and maintenance. Water is a problem since there is a limited supply here on the Eastern flank of the Cascades and since the plants and animals and people all need water to survive. But water can be reused. My first experiments with composting here started with my recognition that there was a lot of good organic matter that was just getting dumped down the drain as I was washing wool. The goat pens had recently been cleaned out and we had weeded the nursery, getting rid of a lot of invasive bull thistles which the animals would not really care to eat, so the time was ripe for getting the compost system restarted.

     The method I am using has three piles -- one just getting started, one halfway done and one pile of finished compost that can be added directly to plant beds. So I cleaned up and organized the compost area, added some signs to let people know that they should put compostable materials in the first pile and take finished compost from the last. Building the new pile was just a matter of alternating layers of higher nitrogen materials with layers of higher carbon materials, and dumping on some rinse water from cleaning fleeces. The very next day after setting things up I already noticed the piles heating up nicely. Today I checked with a thermometer and the internal temperature is in the ideal range to break down organic material and kill pathogens -- 150°F!

     Now it's just a matter of keeping things going. There should continue to be plenty of compostable materials available. Water is an issue though as the mostly rainless summer is upon us. One way to get the water requirement taken care of might be to dump the daily gray water from washing dishes on the pile. It's being used anyway and just going down the drain. That might require switching to a more benign dish soap, one without lots of stuff we wouldn't want to put on the plants.

Notes From Windward - Index - Vol. 69