First in a three-part series.

(photo by flickr user arimoore)

Ontario’s ban on the cosmetic use of pesticides has made a lot of people nervous about weeds. Letters to editors of the province’s newspapers often carry laments from home owners regarding weed invasions and the despoiling of lovely green lawns, parks and sports fields. Many people are at a loss for how to cope with weeds.

The ECO would like to suggest that the solution is close at hand. The application of well-made compost, with the occasional help of a few additional organic inputs, can reduce weeds to the point where a few minutes of hand-pulling from time to time is all that is needed to maintain a green, healthy, weed-free lawn. This is not a matter of just adding compost and hoping for the best. This is science that works.

The Town of Wolfville, in Nova Scotia, provides a good example. David Slabotsky, who manages the parks, gardens, and recreational sports fields for the Town, had been using organic methods of turf management for years but was still having problems with weeds. After attending a workshop where he heard a scientist talk about the importance of beneficial fungi in turf soils, he decided to get some training in the biology of compost and soil and apply his new knowledge to his job.

Within a couple of years of introducing some new methods, weeds have all but disappeared and the soil in Wolfville’s parks and soccer fields is healthy and productive. David uses no pesticides and only a small amount of organic fertilizer. His main tool for this successful program is well made, mature compost. (Read more about this project, and more, in Compost: Appreciating Nature’s Sense of Humus from this year’s ECO Annual Report.)

With respect to weed control, it is important to realize that not all composts are created equal. In general, for a compost to provide optimum benefit, it must have high levels of microbial diversity (there are millions of different species of microbes in a handful of good compost). Properly made, well-aged composts generally meet this requirement.

For fighting weeds in lawns, however, microbial diversity is not enough. This diversity should include significant levels of beneficial fungi. But what are beneficial fungi, why are they important, and how do you know when there are enough fungi in your compost? This blog is the first of a series on how compost – your own, the municipality’s, or commercially produced product – can be used to develop and maintain a lush, healthy and weed-free lawn.

The next blog will look at the science of soil ecology and how the management of the “soil food web” can provide an effective, low-cost, environmentally superior alternative to the use of chemical fertilizers and pesticides. The third and last blog will provide some practical tips on how you can apply these principles to your own lawn.