Can Lawns be Environmentally Friendly?
by Larry Ryan - May 2007
Larry Ryan is a forester and president of Ryan Lawn & Tree. He can be reached at 913-381-1505.Try to imagine life in the city without our lawns and trees. Special moments can be as simple as the smell of fresh grass in the spring or silhouette of your favorite tree against the sky.
Who would want a city that was all asphalt or concrete? Nevertheless, a yard of native prairie or timber, while environmentally friendly, would not be totally livable. First, the risk of fire would be significantly greater and the increase of ticks, roaches, poison ivy and other pests would change the way we use and view our property.
Maybe you’ve read an article recently about the negative environmental impact of lawns. I’d like to suggest that the facts are different. Lawns are an important part of a healthy urban environment. A good lawn will hold the soil and keep it from eroding. In addition, rain will absorb much better in your lawn than on bare ground. Water transpiration from your lawn cools the air, and the turf grass will clean pollutants from the air while adding oxygen to the atmosphere. So, in addition to being environmentally positive, lawns are both beautiful to look at and very usable.
If this is the case, then, what’s the beef? Let’s look at issues that cause people concern and look for solutions. One important concern is the polluting of our streams and lakes. What is the pollution caused by? If you spend any time around urban bodies of water as I do, the first thing you notice is the debris floating on or sunk in the water. You will find cans, bottles, bags, boards, balls, boxes and more. In addition, it is common to see a film of oil here and there on the water. Every bit of trash that is left in or drips on our streets and parking lots has the potential to wash into our streams with each rain. The solution is to not wait for the street or parking lot sweeper. When we see trash, we must all pitch in and pick it up. Our vehicles must be maintained so they don’t leak. Concerned citizens can make a difference.
Algae bloom in our lakes in the summer can kill fish. This is often blamed on excess fertilizer use on lawns. Algae bloom is caused by phosphate. Most fertilizers contain little phosphate. Organic matter is rich in phosphate and is the leading cause of algae bloom. The University of Minnesota researched this issue because clean streams and lakes are so important to their state. Their research affirms the problem is not fertilizer leaching, but is organic matter washing into streams. Where does the organic matter come from and how do we solve the problem? First, urban areas have a lot of hard surfaces that tree leaves and debris fall on. In the spring, look at the catkins (fruiting part) from pin oaks and honey locusts that fall into the streets. Leaves in the fall that end up in gutters and storm water drains are a huge source of organic matter. Much of this debris will be washed into our storm sewers and end up in our streams. The solution is more regular and timely street and parking lot sweeping.
Two more ways organic matter gets into our waterways are when clippings are blown into the street when mowing and the dumping of debris into storm sewers. Solve this issue by simply blowing the clippings back into the lawn after mowing and stopping the dumping. Most of us don’t realize the negative impact of debris in our streams thinking “it’s natural.”
How do we make lawns more environmentally friendly? I can suggest several things, but it starts with good cultural practices. These practices are seeding, watering, fertilizing, aerating, pest control and mowing.
In short, start with good varieties of seed and plant a nice thick lawn. Spot seed with the same varieties of grass each fall to fill in those thin or bare spots that developed during the year. Mow every week once the lawn starts growing. At peak growing times, mow every 4 or 5 days for best results, and leave the clippings on the lawn. This actually allows you to use less fertilizer since you are not replenishing the fertility lost in the clippings. Since the grass is growing spring through fall, apply light feedings through the year, but do the heaviest feedings twice in the fall. Control most pests such as weeds with spot treatments and you will use very little pest control products. (The exceptions are using preventative barriers for grassy weeds and grubs.) Increase frequency of watering as the temperature climbs. In the spring and fall, watering every other week is usually sufficient. In the summer, you may need to water every 2 to 4 days. Depending on the type of grass and soil, we recommend aerating every year or two.
Put all of this together and you will have a lawn that is both aesthetically and environmentally friendly. Taking care of our environment should be a personal commitment. Let’s make that commitment and get off to a good start this year.