THE GREEN THUMB ALMANAC 

Your Online Gardening Information Center

Composting

On This Page:

  • Composting Formula
  • Micro/Macro Organisms
  • Composting Methods
  • Types of Bins
Composting is the process of breaking down plant materials, such as leaves and grass clippings, to a more usable organic soil amendment or mulch.  Properly prepared compost is free from weed seeds and offensive odors and rich in nutrients that plants need.  Compost can help to loosen clay soil or to hold moisture and nutrients in sandy soil.  Most importantly it allows us to recycle garden and yard waste into a valuable, usable product, reducing the amount of solid waste going into landfills.

Organic Matter + Micro/Macro Organisms + Oxygen + Water + Heat = Compost!

The first thing you need to start composting is organic matter.  Organic matter is what you put into your compost bin or pile.

What you can use:  Sod, Grass Clippings, Leaves, Hay, Straw, Manure, Chopped Corncobs, Corn Stalks, Sawdust, Shredded Newspaper, Wood Ashes, Plant Refuse, Kitchen Scraps.

What you should avoid:  Coal, Charcoal, Colored Paper, Diseased Plants, Non-biodegradable items, Pet Litter/Feces, Sewar Sludge, Toxic Chemicals, Weed Seeds, Food scraps containing - Grease, Fat, Meat Scraps, Bones, Dairy Products.

Organic matter is often described as "browns" or "greens."  Browns are the dry, tough, fiberous plant material such as leaves, straw, sawdust and cornstalks.  The "browns" are your energy source (Carbon).

"Greens," also known as activators, are things like manure, grass clippings, green vegetation, blood meal or kelp meal.  These are your protein source (Nitrogen).

The optimum Brown (Carbon) to Green (Nitrogen) ratio is 30:1.

Micro/Macro Organisms

So how do your "Browns" and "Greens" become useable compost?  Mother Nature has a team of experts who break down and convert plant materials into compost.  Come and meet the team!
 
Bacteria!  Not all bacteria are bad.  There are three beneficial strains of bacteria which help to break down plant material.  These are the Psychrophiles (active between 28-65 degrees F.), the Mesophiles (active between 40-110 degrees F.),  and the Thermophiles (active between 100-160 degrees F.)
 
The rest of the team is made up of:  Fungi, Actinomycetes, Enzymes, Earthworms and Insects.

There are two items that our composting team needs to function, they are Oxygen and Water.  Our composting team works best in an aerobic (oxygen) not an anaerobic (non-oxygen) environment.  Our team also needs water to survive.  The optimum moisture content of your compost pile should be between 45-50%. 

All of this activity will generate heat.  Composting occurs between 28-160 degrees F., with the optimum temperature being 70-90 degrees F.

Composting Methods

There are several methods of composting, some work faster than others.  These include:

  • The Heap- just pile it, no structure, cheap but untidy.
  •  The Holding Bin - a box or wire fence, cheap, low labor, small scale only, slow.
  • The Turning Bin - requires maintenance, fast, larger volumes.
  • Soil incorporation - bury it, low labor, cheap.
  • Worm Composting - works in cool temperatures (50-80 degrees F.), can do indoors.

When making your compost pile we recommend the "lasagna" method.

Chop your material into small pieces (1/4" is ideal) and layer them as shown.

 soil

 high nitrogen material (Greens)

 dry rough material (Browns)

 soil

 high nitrogen material (Greens) 

  dry rough material (Browns) 

Water each layer if the material is dry.  Use a compost thermometer to measure the temperature of your pile.  A good mix will  reach 110-120 degrees F. in 3 days.  When the temperature of the pile begins to drop a little, turn the pile for aeration.  If it is not hot enough add more nitrogen (Greens).  The pile  should reach 130-140 degrees F. after the first turning and should be turned every second or third day.  When the pile no longer heats up, no matter how much turning (temp. less than 110 degrees F.) the composting process is complete!