How to Be Successful at Composting
As an avid gardener and as someone who is conscientious of my environment, I purchased a compost bin several years ago. I have an abundance of yard and lawn clippings that I am not willing to dump into our already stressed landfills. In turn, my efforts for composting benefit me greatly because I can use this finished material to improve my soil texture, the soil's ability to hold water, and as a fertilizer.
Composting is a biological process for converting organic solid wastes into a stable humus like product. Within a compost pile, microorganisms attack organic substance, breaking it down and producing rich organic matter (Golueke,13). For this to occur, several things need to take place, two of which are a proper pH balance, and the correct carbon to nitrogen ratio.
The level of hydrogen ions in a solution, a measure of its relative acidity or alkalinity, is expressed in a number called the "pH' (Raven, A‑3). The pH scale runs from zero (extremely acid) to 14 (extremely alkaline). The middle of the scale is the neutral point and desired point. The pH is worth measuring because you can follow the process of decomposition. Soil pH affects plant growth in many important ways. It affects the root's ability to absorb water and nutrients, it has an effect on the solubility of toxic substances, and it has an effect on soil microorganisms (Sinnes, 26).
During the initial stages of decomposition, organic acids are formed. These acidic conditions are favorable for growth of fungi and breaking down lignin and cellulose. As composition proceeds the organic acids become neutralized, and the mature compost generally has a pH between 6 and 8 (Newberry).
Three important things you need to know about pH are testing your soil, what the optimum pH is for the plants you care to grow, and how to correct an overly acid or alkaline condition. This can be done a number of ways. Most county agriculture departments will supply you with a soil test kit or with a phone number to obtain a kit. There is also pH paper on the market along with a more elaborate method known as "compost extraction" (Trautman).
When taking a measurement of the pH, it is important that several readings are taken because your compost is unlikely to be homogenous. It may contain anything from sawdust and grass, to lettuce and coffee grounds. If your pH reading is between 6 and 7.5, most plants will do well in this type of soil. If the pH is 6 or below, the soil is probably too acidic and you will need to add lime to the compost, such as ground chalk or a limey clay (Sines,27). This solution can be said to contain more H+ ions than OH‑ ions. Many plants such as azaleas, hydrangeas and blueberries love this type of soil. If the soil has a pH above 6, it is too alkaline and contains more OH‑ ions than H+ ions. You will need to add "brown" material such as pine needles or sawdust to counter act this condition (Golueke,83).