Using Compost

compost truck

Dianne Westlake

Without the naturally occurring phenomenon known as decomposition or composting we would be sinking into great masses of dead plant material. In fact our planet would be uninhabitable. Nutrients would not be available for plant growth, soil would become compressed as air spaces collapse and water would run off causing erosion. As essential as light and air, if there were no composting, our world would be a barren wasteland.

Composting is an essential process in which dead plant and animal material is attacked by microorganisms in the soil as well as small animals and insects like earthworms and millipedes. Our woodlands provide a perfect model of natural composting; trees lose their leaves in the fall, layering the ground with a thick mat that offers protection for the plants and small animals over the winter. These leaves break down throughout the year freeing the nutrients for consumption and adding to the soil texture and health. Nature’s perfect recycling programme.

Chemical fertilizers, even when applied as directed, deliver nutrients in greater amounts than can be assimilated by plants and soil. Thirty-five percent of nitrogen and fifteen to twenty percent of phosphorous and potassium is washed away, much of which ultimately affects the ecosystem of our rivers and lakes. There are no other benefits for the soil. Applying chemical fertilizer achieves only one function – a quick-released supply of nutrients.

On the other hand, yearly applications of compost contribute to the overall health of the soil and the plants. It will not cause burning like chemical fertilizers. Adding organic material alters soil structure making both sandy soils, which will not clump and clay soils that compact when wet, more granular. Aeration is improved with increased pore spaces allowing air to reach the root zone. Air is vital to the many beneficial soil organisms and fungi as well as for the transformation of minerals to the forms that are usable by plants. Soil's ability to retain water increases with the addition of compost. One pound of humus will hold almost two pounds of water. Water and wind erosion, often the end result of the loss of soil fertility and poor soil structure, can be controlled by the systematic addition of compost. In addition, soil temperature is moderated.

Nutrients are provided to the plants in small quantities, as they are needed, instead of in one gigantic dose. Just as we need a variety of vitamins to maintain our good health, plant need more than simply a supply of nitrogen, phosphorous and potassium (N-P-K), the three numbers you see on the chemical fertilizer bag. Micronutrients like iron, cobalt, manganese, zinc, copper, etc are needed in small quantities but are essential for the plants' good health, growth and reproduction.

Healthy soil provides an environment in which earthworms, remarkable, beneficial creatures that are nourished by soil and organic material, are able to live and multiply. Over time, as they consume and digest their own weight in organic material and soil every day, the PH is altered: acidic soil becomes less acid and alkaline soil less alkaline. In addition, the earthworm's digestive tract produces secretions that with the help of microorganisms is able to free up plant nutrients (N-P-K) and micronutrients.

In our own garden, we have found that topdressing our perennial beds with at least an inch or two of well-finished compost has reduced the number of weeds, another time and back saving benefit. This layer is not dug into the bed, which would bring weed seeds to the surface. Instead, it is left on top to act as a blanket blocking the light that is frequently needed for the weeds to germinate. All of our flower beds, vegetable garden and lawns are given a substantial topdressing annually. Because we cannot produce enough from the material generated on our own property, we purchase at least one large load of compost from the City of Peterborough Waste Programme every year. This finished compost is free of seeds and disease.

Compost is available by the load by calling the Waste Reduction Office at 742-7777 extension 1657. Smaller quantities are available at Peterborough Green-up’s Ecology Park on Ashburnum Drive.