Monday, March 25, 2013

The ABC's of Composting

 The popular practice of composting is defined as the process by which organic materials biologically decompose under controlled conditions. Perhaps the most notable point about composting is not to make it more complicated than it is.  By merely throwing a pile of twigs and leaves in the back corner of the garden, you are composting; of course, it may take a year or so to breakdown.  But by following a few simple, but vital rules you can speed up the process and produce good compost in about a month or so. The following some are key principles:

 a. Proper moisture and air (oxygen) content - Compost works best if the moisture content of the materials is about 50%.  That’s not easy to measure, but it has been estimated to be about the moisture content of a wrung-out sponge.  If the material is too dry, decomposition will stop; if too wet, oxygen is excluded and decomposition will slow and odors will be produced.

b. Proper carbon/nitrogen ratio - For effective composting, the raw materials must have a proper carbon/nitrogen ratio – set at about 30:1.  Since this too cannot be easily measured, experience has shown that mixing equal volumes of green plant material with equal volumes of brown plant material will give this ratio. The greens are fresh moist materials like grass clippings, weeds, manures and kitchen scraps. The browns are dry materials such as twigs, wood chips, straw, saw dust and paper.  If a pile of twigs are thrown to the side, they will eventually decompose. When leaves (greens) are combined with the twigs (browns) in the proper ratios, decomposition will occur more rapidly.    
Mixing grass clippings with twigs or chips is not only good for obtaining the proper ratio but also helps to maintain a good oxygen level.  Grass clippings or shredded papers alone tend to mat and exclude oxygen.  Adding twigs helps to open the pile allowing a better movement of air.   

c. Proper size of material - Soft, succulent plant tissue doesn’t need to be chopped into small pieces because it will decompose rapidly. Woody materials, however, will decompose better if pieces are ½ to 1 ½ inches in size: the smaller the pieces the quicker the decomposition.

d. Proper pile size - The size of the compost pile is important.  The minimal size is 3 cubic feet (3x3x3). Maximum size would be around 5x5 and as long as desired.

e. Proper turning- Turning the pile is not required but will certainly speed up the process if turned every day to every ten days. Turning helps ensure proper air circulation, moisture and heat distribution. 

What should NOT be put into the compost pile? Meat, fat, manure from meat-eating animals as well as human waste. Manure from herbivores such as goats, cows, horses, rabbits and even elephants can be used.  It is not good to throw diseased plants into the compost pile, because the pile may not reach the temperatures that are required to kill plant diseases and weed seeds. 
Finally, here’s how to know when the composting is finished: when the majority of the pile has become dark, loose, crumbly and sweet smelling.  Also, the original materials will not be recognizable with the exception of a few pieces of tough woody material. 

Composting is a good way to reuse our natural resources, recycle nutrients and add good organic matter back into the soil.