MAINE–(ENEWSPF)–October 3, 2011.
Out on the road last week after an extended period at home or in my office, I was reminded that not EVERYONE understands the principles of organic lawn care. It’s often easy to get comfortable in one’s cocoon and it’s useful to be reminded that, many times, new ideas are worth repeating.
So I thought I’d begin this week by trotting out some of the principles of our organic lawn program, beginning with an excerpt from probably the most popular chapter in our best-selling book, The Organic Lawn Care Manual (Storey, 2007).
It’s titled Listening to Your Weeds:
For many of you, this is probably the definitive chapter of the book. When it comes to natural lawn care, the real question isn’t so much about how to grow grass, is it? The real challenge is how to eliminate everything else that wants to grow in your lawn. We have long called these unwelcome plants “weeds,” which in the famous quote by Ralph Waldo Emerson are defined as “any plants whose virtues have not yet been discovered.”
Emerson was clearly from the nineteenth century. In this modern world, in which some of us barely take the time to meet our next-door neighbors, we’re not all that interested in getting to know the virtues of any new plants, especially anything that is roguishly trying to invade our outdoor carpet of green. We’re a society of grass snobs who want every blade in the lawn to look and feel exactly the same. I was one, and still am, to a degree. In this environment, a weed is defined as any plant trying to sneak in a little ethnic diversity.
Traditional lawn care since the late 1940s has feasted on a one-size-fits-all approach to weed control that paints every plant with the same broad stroke. Grass is good; everything else is bad. It’s a simple tactic, requiring as little brain matter as possible on the part of the homeowner, the turf professional, and the marketing industry. It’s also just about the most unnatural thing in the outdoor world.
This chapter, like the rest of this book, will ask more of you. For the minimalists, I’d have you ignore the fact that not everything on your lawn is grass and just mow whatever is managing to grow. That’s natural lawn care in its simplest form. To achieve the greater goal of a natural “weed-free lawn,” however, you may be required to think, to meet some new plants, to occasionally use physical exertion, to learn some new techniques and products, and possibly to look at the world outside your door in a whole new way. And what a blast it is when you do. It’s all about tracking the clues provided by nature, as if your lawn were a giant board game. Colonel Moss. In the shade. With compaction. Mystery solved!
Approximately 1,775 plants in the United States have been classified as weeds, and entire wonderful books have been written on the subject. Weeds and What They Tell, written in the 1950s by a German biochemist named Ehrenfried E. Pfeiffer, is especially enlightening. “Weeds are weeds only from our human egotistical point of view, because they grow where we do not want them,” he wrote in his introduction. “In nature, however, they play an important and interesting role.”
The RILE Approach
In the Weed Identification Guide starting on page 184, I focus on only about 40 of the most common lawn weeds, including what they look like, methods of control and, most importantly, what the weeds tell us about our soil. This Guide is the cornerstone of what I call it the RILE approach to weeds: Relax before you act, identify your weed, listen to your weed and, if necessary, eradicate your weed. If you can develop a basic understanding of RILE, you’ll be well armed against all weeds and off to a great start in your quest for a natural lawn.
We’ve been masterfully programmed. A devilishly inventive advertisement for a popular synthetic weed killer depicts a man climbing the sheer face of a high mountaintop. After braving the elements and exerting himself to the highest degree, the climber finally reaches his destination and pulls his spray bottle of herbicide from his holster as if it were a six-shooter. Heroically, he sprays the single dandelion emerging from a crack in the granite.
The ad’s message, clever as it may be, is also tragically sad. As this chapter details, many plants actually provide significant benefit to the soil and therefore your lawn. Wide swaths of just turfgrass, if left alone, are dependent systems with no ability to feed or sustain themselves. Add in a little white clover or bird’s-foot trefoil, though, and you’ll give your lawn the tools it needs to take care of itself — except for the mowing, of course.
The best first step in natural weed control is to take a deep breath and make an honest evaluation of your weed population. A rule of thumb is that if you have anything less than 10 percent weeds in your grass, you don’t have a weed problem worth treating. Anything more than 90 percent perfection isn’t even reasonable to expect in a backyard setting. If you have 10 to 60 percent weeds, you may want to take some of the actions outlined later in the chapter. If more than two-thirds of your lawn is covered with weeds, in our lawn-as-a-board-game scenario, do not pass “Go,” do not collect $200, and go straight to jail. You can only come out when you’ve read chapter 5 about how to start over the right way.
Let’s begin with a primer. On one hand, lawn weeds are generally quite convenient to classify. They are either grasses, such as crabgrass, quack grass, and Bermuda grass, or they are broadleaf weeds, such as dandelion, ground ivy, and chickweed. Botanists will further explain that weedy grasses are “monocots,” meaning they emerge from their original seed with a single seed leaf. Broadleaf weeds are “dicots,” meaning they have two seed leaves at the time of germination. That’s good to know when plotting your natural approach to weed eradication, because you always want to get rid of weeds when they’re small. You also want to know if the weed is an annual, biennial, or perennial in your climate zone, because this will affect your method of control.
Annual weeds germinate from seed, grow, send up flowers, and produce new seed all in the same growing season if we allow them to live that long. They’ll ultimately be killed by frosts. With annual weeds, therefore, careful management of the weed seeds is critical to reducing population of the plant. Never allow a weed to produce seeds if at all possible; mow or pull the weeds instead.
Biennial weeds have a two-year life span. They store food reserves in the roots for the first year and then flower and set seed in the second year. Their control is most closely associated with that of annuals. In other words, if you don’t let biennials go to seed, you’ve got a leg up in the battle.
Perennial weeds also germinate from seed, but they can also populate themselves through runners known as underground rhizomes and aboveground stolons. They won’t die off in the winter, which generally makes them far more of a nuisance to control, even through traditional synthetic chemical treatments. If you simply try to dig them out, and don’t get every speck of rhizome or stolon, they’ll typically grow back even stronger. The best tactics, therefore, involve changing the soil conditions that are allowing the weed to thrive.
If you read about soil in chapter 3 and are beginning to think of your lawn as a living body much like your own, you know that not all plants and soils can be treated equally. Part of the reason so many people fail in traditional lawn care programs is that they attempt to treat the entire yard with the same chemicals, which don’t always work on all plants. Broadleaf herbicides won’t touch weed grasses, for example, and generally do a poor job of eradicating many perennial weeds. Preemergent herbicides, similarly, won’t do a bit of good on a perennial weed that’s already established.
Having said all of this, I should tell you that you can grow a decent natural lawn without ever knowing the name or type of a single nongrass plant. Treat the soil well (chapter 3), pick good grass seed (chapter 4), and generally follow the rest of this book’s advice, and it won’t matter terribly if you don’t know creeping Charlie from bugleweed. But if you’re going to go to war with lawn weeds, it’s imperative to know who and what you’re fighting. To meet some of the likely suspects, turn to the Weed Identification Guide on page 184. Your local Extension agents, most of whom are now online, will usually have fact sheets on other weeds prevalent in your area but not listed here.
The essence of organic weed control comes down to this premise: Most of those other plants that pop up in your lawn are trying to tell you a story about your soil. Sure, you can kill the messenger by instantly eliminating the weed from the lawn with the right tool. But pulling or spraying the weed doesn’t change the underlying tale that the plant is trying to convey. Just as your grass needs certain conditions to thrive — from a balanced pH to adequate organic matter, moisture, soil life, and fertility — weeds have their own needs, and their presence in your lawn should be seen as valuable indicators.
Have you ever wondered, for example, why crabgrass always seems to crop up right next to the driveway? Maybe you dig up the crabgrass, but then a new batch grows right back? It’s because the crabgrass is trying to tell you the soil is compacted from all the feet, automobile tires, and plow blades that wander off the edge of the pavement. Until the compaction is remedied, you will always have crabgrass — or plantain, chickweed, or knotweed — in abundance. I have a perfectly nice neighbor who has been by a few times to expedite my landscape projects with his backhoe. Bless him. During one recent visit when I wasn’t home, though, he drove the tractor right across my new lawn out front. I’m not generally a violent guy, but I wanted to strangle him. If I don’t aerate the soil under those tire tracks, his visit will be marked by telltale trails of plantain for years to come.
The stories of weeds are many. Before you ever get a soil test, the presence of certain plants can tell you about all of the following: soil pH, soil life, moisture or drought, soil temperature, drainage, organic matter, fertility, tillage, soil structure, and the aforementioned compaction. To learn the story every plant has to tell in detail, I realize, is a tall order for anyone except the most dedicated of horticulturists. I have observed many weed tendencies myself through my years as a landscaper and homeowner, but I have also learned much from the work of others. A special thanks again to Ehrenfried E. Pfeiffer, who was a protégé of Rudolph Steiner, the father of biodynamic farming and gardening, and to people like the late agronomist Carey Reams, who taught us that each weed species is genetically programmed to replace specific deficiencies in the soil. These groundbreaking scientists showed us that nature is always trying to find a balance. They proved that if your lawn is missing nitrogen, nature will often send in clover or one of its cousins in the legume family of plants, which can trap and process nitrogen from the atmosphere (see page xx). If your lawn, conversely, has too much nitrogen, nature will likely give you an abundance of dandelions — and insects — to feed on the excess. Listening to your weeds can be an enormously powerful tool.
My friend Pat Lewis still remembers his first day of classes at the University of Massachusetts, Stockbridge, back in the early 1980s. Dr. Joseph Troll, the renowned instructor, told the would-be golf course greenskeepers “the best tool against weeds is a healthy grass plant.” This is a point on which the traditional lawn care industry and the natural lawn care practitioners agree. A nice, lush stand of turf will resist weeds by blocking the light needed to germinate weed seeds. Getting to that verdant green carpet is where the two lawn care communities differ. Killing weeds by synthetic means often requires multiple applications of chemicals each year, and no one chemical application will work for all weeds. The EPA estimates that only 2 percent of the active ingredients in weed killers, which are called herbicides, ever reach the target plant. The other 98 percent goes into the soil, the groundwater, and the atmosphere, onto other nontarget plants, or elsewhere in the environment.
After many years as a successful superintendent at golf courses in New England and countless sessions dressed as a white-suited spaceman atop the chemical sprayer, Pat Lewis reached a watershed conclusion.
“I thought Dr. Troll was right,” he said. “But maybe there had to be a better way to get the grass healthy.”
Pat proceeded to take the lead in converting his course, the Portland Country Club in Falmouth, Maine, to a natural approach to growing grass. In time, his course became the first in Maine to be certified by the Audubon Society’s Cooperative Sanctuary System, which requires limiting weed killers and other pesticides. Hundreds of other courses around the country are also now certified. I tell you this by way of example. If a golf course can create championship conditions without using weed-killing chemicals, you can certainly grow a nice natural lawn around your home.
Getting Rid of Weeds
If you have relaxed, identified, and listened to your weeds and are now ready for eradication, you have six primary tools at your disposal:
1) total weed wipeout with nonselective sprays or solarizing techniques
2) spot weeding with nonselective sprays, flaming, or mechanical tools
3) preemergent weed control in spring and fall
4) soil modification that gets to the root of the problem
5) overseeding with new grass seed to crowd out weeds
6) mowing at appropriate heights and only occasionally using a bagging attachment on your mower
These are techniques practiced by a growing number of golf course professionals and natural lawn care practitioners, and they are easily emulated.