Wednesday, May 3, 2017

Paul Hetzler: Keep Off the Grass

lawn careAs a kid of about five, I became suspicious of lawns. In a rare moment of TV viewing, I had seen a public-service ad wherein a bundle of green leafy stuff thudded into an eerily vacant playground while a baritone voice boomed out something like “Grass. We think it’s bad for kids. Stay away from it.” My mom insisted this was “bad grass” which did not grow in our yard. However, she declined to elaborate, which fueled my mistrust. So I kept off the lawn a while.

These days, “bread” is no longer money, “mint” is just a flavor, and the pernicious leafy stuff mostly goes by other names. There is only one grass, and it is almost time to cut it again. Jargon may change, but things like paying taxes and mowing lawns don’t seem to.

Across the region, a bewildering array of lawn-care products have sprouted at big-box stores and garden centers. It’s easy to spend a lot of dough — I mean money — on fertilizers, weed killers, and seed, but hard to make sense of which products are right for you. Before you shop, here are a few thoughts that may help sort things out.

First, grass is not for everyone. Or everywhere. If an area does not get 4 or more hours of full sun daily from March through September, trying to grow grass there is a waste of time. Steep slopes and high-traffic zones probably need something other than grass, too.

Comparison spells trouble. Well not literally, but it’s mighty unfair. Fashion models have airbrush artists and makeup consultants. Golf courses have full-time turf experts and a massive budget. With good information and a little work, we and our lawns can both look good, but let’s not compare with deep-pocketed pros. In the words of Dr. Frank Rossi, a leading Cornell Turfgrass Science researcher,

“Chances are you can grow a pretty good lawn without using insecticides, fungicides, or herbicides. You may even be able to do it using little or no chemical fertilizer… Will your lawn look like a putting green? No… But if you arm yourself with an understanding of what grasses need to thrive, and commit to a long-term plan to meet those needs, you can grow a perfectly acceptable lawn…”

Get the dirt on your soil. If your grass looks bedraggled, fertilizer may not be the answer; in fact, early-season nitrogen can weaken grass and make lawns worse in the long run. At the very least, get a soil pH test — a pH more acidic (lower) than 6.0, or more alkaline than (above) 7.0 will hinder plants’ ability to absorb nutrients. The majority of samples I get at the office have pH values too high for healthy lawns, sometimes 100 or even 1,000 times too alkaline due to annual lime treatments. Lime is only good if it’s needed.

If it has been over three years since the soil was tested, you may want to invest in a lab analysis. For under twenty bucks you can get nutrient levels, with specific recommendations, plus pH and salt content. This last item may seem odd, but fertilizers, herbicides, wood ash and deicing agents are all sources of salt, which can damage soil structure, harm microbes, and aggravate water stress. Only fertilize based on soil test results, and only use nitrogen in the fall.

Nature abhors a vacuum, which is why I keep mine hidden away indoors — no sense offending nature if you can avoid it. This hatred of emptiness means that if you don’t re-seed bare (and weak) spots in the lawn, she’ll fill it with whatever is handy, probably weeds. Edging along the sidewalk or driveway may produce the look you want, but it also produces a lot of bare earth, so if you have a weed issue, especially crabgrass, breaking this habit will give you an edge on weed control.

Another type of vacuum is a close-cropped lawn. Not only does close mowing cause weak, stunted grass roots (and thus plants), it allows the sun full access to the soil. This gives weeds a tremendous advantage. Have trouble with ground ivy? Put away the vacuum. Stop shaving the earth and start mowing the grass.

The most important thing you can give your lawn is more of its hair. Studies show that changing from a grass height of 3.5 inches leads to a vast improvement in lawn health. Leaving grass longer will greatly reduce weed pressure, lawn diseases, and fertilizer requirements. Perhaps the most dramatic change with longer grass is a lasting drop in weed population.

If you need to use herbicides to reduce weeds, follow the label instructions closely. Some broadleaf (selective) herbicides contain chemicals that may stress or injure trees. Pre-emergent herbicides inhibit weed germination, and are used for crabgrass control. Apply pre-emergent products around the time forsythia flowers are starting to drop.

Another tip is not to mow more than a third of the grass at a time. For example, to maintain a 3.5-inch turf height, mow before the grass gets over five inches high. Keep to keep the blades sharp — it can help reduce disease, plus it looks nicer and saves on mower gas. And it almost goes without saying that grass clippings belong to the lawn, not the landfill. Leave the clippings — that’s your fertilizer.

White grubs — we have five species in northern NY — can become a problem if there are more than ten per square foot of lawn. Several nontoxic and low-toxicity treatments have come on the market in the past few years, but timing varies for all of them. Milky Spore treatment is safe, but is not effective up north due to cool soils. You can also use beneficial nematodes to kill grubs. See the website below for more details.

There are many solid lawn-care resources out there, but always check the source, which should be from .edu or .gov sites. Cornell Senior Extension Associate Lori Brewer has assembled the work of many experts, including Dr. Rossi, into a comprehensive 47-page book entitled “Lawn Care,” which is free, here.

I think it would contribute to a better world if we teach our kids to stay grounded, and to let the grass get high.

Photo courtesy Cornell University.


Paul Hetzler

Paul Hetzler is the Horticulture and Natural Resources Educator at Cornell Cooperative Extension of St. Lawrence County.

You can reach Paul at the Cornell Cooperative Extension office in Canton at (315) 379-9192.


Tags: ,


2 Responses

  1. Bill Ott says:

    I like your advice of just cutting one third of the grass at a time, because usually I am tired of mowing when I am about 25% done. As far as measuring grass height, does one pull it straight up, or just stick his stick in the turf. And just what kind of grass do you grow at Cornell, anyway?

  2. SwilliAm says:

    Mow high, mow often, and keep the blade sharp. Nothing else needed for a good lawn. Simple as that!

Leave a Reply to SwilliAm

Leave a Reply to SwilliAm Cancel reply

Your email address will not be published. Required fields are marked *