Composting Guide (Continued)

How to Build A Compost Pile

The first thing one must consider when building a compost pile is location.  Ideally, it will be built near the place where the compost will be used.  It should be located away from neighboring homes so that any odor it produces will not become a problem.  You should also shield it from view of your home and neighboring homes.

Compost piles should be built away from water sources such as wells, streams, and ponds.  Make sure that runoff from your compost pile cannot run downhill into such water sources.  Avoid building compost piles near trees since their roots can grow into the bottom of the pile making the compost difficult to turn.  Avoid locations prone to drying winds and constant sunlight to minimize the amount of watering the pile will require.

Finally, every situation and set of conditions are a little different, so consider everything discussed in the previous section about factors that affect composting and use common sense. 

Fast Compost Recipe

“Fast” compost recipes can produce compost in two months or less, but it is more labor intensive.  It requires frequent turning, so you may want to consider a compost tumbler or turning bin.

Before starting collect a cubic yard (3’ x 3’ x 3’) of “browns” (high carbon materials) and “greens” (high nitrogen materials).  Be sure to chip or shred all large materials as this will increase surface are and the speed at which they can be decomposed.

In your compost bin or compost tumbler/turning bin, create a 4- to 6-inch layer of browns. If manure, wet leaves, or other bulky material are used, then add dry bulky material like wood chips or straw to improve the porosity of the layer. 

Add a 4- to 6-inch layer of greens which can contain vegetable kitchen waste as well.   If using grass clippings or other greens very high in nitrogen you may want to make the greens layers thinner than 4 inches.  Add another thin layer of browns containing soil, sawdust, leaves, straw, etc. to help absorb the odor if food waste is included in the green layer.

Test the moisture in the compost layers by squeezing a handful of the material.  You should get one or two drops of water.  If not, then add a little water.  Be careful not to add too much water as this can lead to leaching of nutrients.

If you would like to ensure the compost is inoculated with decomposing microbes, you can apply a thin layer (about 1/4th inch thick) of soil or finished compost between the layers of materials.  However, this is typically not necessary as the other organic yard materials likely have enough microorganisms to cause decomposition.  You should not need to purchase a compost starter or inoculum as the microbes in the soil or organic waste in the pile will multiply at the same speed as microbes in an inoculum.

If you are only using tree leaves in the pile, add high nitrogen fertilizer between the layers to speed up decomposition.  About 5 ounces of 10% nitrogen fertilizer should be added to the pile for each 20 gallons of hand compressed leaves.

Repeat the above process until the bin is full.  Remember to test each section for moisture as you go and add water as needed.  Once the pile is 3- to 4-foot high, if not using a tumbler or turning bin, make sure the top of the pile slants to the middle to capture rain.  If you cover the pile with a tarp or other cover to prevent it from getting too much rain, make sure the cover does not touch the pile as this may inhibit aeration.

Once your compost pile is done, you will likely want to create a calendar to remind you to do several things which need to occur on a regular basis:

  • Check the moisture levels in the pile: Grab a handful of composting materials.  It should feel moist, and you should be able to squeeze one to two drops out of it.
  • Check the temperature of the pile: The temperature of the pile should be checked regularly with a hotbed thermometer.  You should check the temperature at least 12 inches deep in the pile. It should max out between 90° and 140° F. Once you notice the temperature of the pile falling or if it reaches 140° F, then you will want to turn the pile.   Once turned, the pile’s temperature should begin to rise again if decomposition continues
  • Turn the compost every 3-5 days: While turning a pile can speed up decomposition, it can also cause temperatures to drop as it releases heat into the air. When turning the pile, make sure that materials from the top and outer edges are rotated to the bottom and middle of the pile each time.  If you have two or three bins, then this is much simpler as you can move the compost from one bin to another each time your rotate.

Continue monitoring moisture and temperatures and rotating the pile regularly.  If you turn the pile and temperatures do not rise again, then check the compost material using the “look and touch” technique.  If the material is dark, crumbly, and no longer resembles the original material, then it is probably ready.  If ready and using 3 bins, then the material can be put in the 3rd bin.  However, if it is not ready, then you may need to add water or more nitrogen to the pile.

Curing Your Compost

Once the pile stops reheating after turning, the curing stage begins.  It is important to allow your compost to cure so that any remaining large particles, clumps, resistant compounds, and organic acids can finish decomposing. If you do not allow your compost to completely decompose, then it could be toxic to seedlings and newly established plants.

As the compost cures, the pH level of the pile moves toward neutral, the C:N ratio drops, and more humus is produced.  Once the pile temperature falls to that of the surrounding air, then curing is likely done if the pile has not been starved of oxygen or allowed to become overly dry.

Slow Compost Recipe

Instead of “fast” composting which takes only 2 months in many cases to produce compost, most homeowners without large amounts of yard trimmings use “slow” composting.   It requires much less time and labor.  “Slow” composting can take between 6 months and 2 years to produce compost.

The bins used can be constructed form by nailing together wooden pallets to form the walls of the bin.  You can also construct a bin from chicken wire by cutting slits into the sides and bottom of a standard yard garbage can to allow for ventilation and drainage, respectively.  Ideally, the bin will be positioned a foot off the ground.  If this is not possible, then start the pile with a 6-inch layer of small twigs or corn stalks to allow for good airflow beneath the pile and drainage.

You use the same ingredients for “slow” composting as you do with “fast” composting.  Add ingredients to the pile as they become available.  Adding diseased material to the pile is typically not recommended since “slow” composting does not generate the 130° F temperatures required to kill most pathogens which could get reintroduced when the compost is used.

Turn the pile occasionally to improve aeration and to avoid anaerobic conditions where the pile becomes starved of oxygen.  If the pile develops a foul odor, it is likely in an anaerobic state and requires turning.  Turning the pile helps to mix the materials and break up any clumps that may have developed.

Once the pile has been allowed to decompose for 6 months to two years, compost from the bottom of the pile should be ready for use.