Weeds, those aggressive, irrepressible pests, are the most persistent — and annoying — problem of lawn care. Surely that’s why Paul Tukey in his classic guide, "The Organic Lawn Care Manual," labeled his organic method for their management with the acronym R.I.L.E.: Relax, Identify, Listen, and Eradicate.
Weed control is a matter of chemical warfare for the typical home greenskeeper, of spreading large sacks of toxic materials across the lawn. It’s the epitome of the blunt instrument — everything gets dosed with herbicides in the pursuit of occasional malefactors such as dandelions and crabgrass. As Tukey notes in his book, an Environmental Protection Agency study found that of all the countless thousands of tons of toxins spread in this fashion, just two percent of them reach the intended target. The rest goes elsewhere: into the soil, into nearby wildlife or waterways, picked up by the feet of pets and children, or it escapes into the atmosphere as a toxic gas.
Tukey’s book is not new; it was first published in 2007. But it is still as relevant now as it was when it was hot off the press. All you need to do is visit a big box store during weed season and look at the stacked bags of toxins to know that the pollution is as bad now as it was a decade ago. Likewise, it’s just as timely to try and see weeds in a new light. Because if we take the time to learn about them, weeds have much to teach us.
It’s worth noting that Tukey’s R.I.L.E. prescription starts with “relax” and that’s often the best thing to do with lawn weeds. If your lawn is 10 percent or less occupied with weeds, Tukey recommends just ignoring them — greater perfection isn’t attainable in a home lawn. If the weeds are more abundant than that, you may want to take action. Start by identifying the weeds. Tukey’s book has a good field guide to the most common types, together with information about what each type of weed tells you about the condition of your soil and lawn. “Listen” to the weeds.
Crabgrass, for instance, is commonly a symptom of compacted soil; that’s why it’s particularly common along the edge of paths, sidewalks, and driveways where there is extra foot traffic. Core aeration of the soil, administered now, will help relieve that condition. In my experience, crabgrass is often the result of mowing the lawn too short. Raise the blade of your mower to three or four inches and your lawn will suffer from less weed invasion in general and crabgrass in particular. Dandelions, by contrast, are usually a symptom of calcium-poor soil and a low pH, two conditions which are easily addressed by an application of lime.
To “eradicate,” the fourth part of Tukey’s prescription, I highly recommend (as does Tukey) overseeding. Research at Cornell University has found that a series of overseeding treatments applied in late summer and early fall is very effective in thickening lawns and reducing the opportunity for annual weeds such as crabgrass the following year. To follow this herbicide-free treatment, spread fast-growing perennial ryegrass seed over your lawn with an ordinary drop or rotary spreader at a rate of three pounds of seed per 1,000 square feet. Repeat this process at two to three week intervals three times and by late October you should have a thick lawn which will be quite weed-repellent the following spring when weeds ordinarily start to invade.
Reducing the quantity of weeds in your lawn is part of a process, for according to Tukey the best defense against weeds is healthy grass, and that is the result of a holistic organic program.
For more information about that, listen to a conversation with Paul Tukey on the Berkshire Botanical Garden’s Growing Greener podcast, at thomaschristophergardens.com/podcasts/listening-to-your-lawn-weeds.