By Steven Cline, Ph.D.
There is much confusion with the term “sustainable” as it pertains to gardening. The general interpretation relates the actions we take today with its impact on the resources of tomorrow. So, you could ask the question, are we wasting resources for more than it is worth and what alternatives are out there that might offer lower energy costs. It’s a big question that should be addressed in a practical manner for each part in the management of landscapes.
At home, we gardeners deal with lawns and gardens of all types. By sheer area, lawns dominate the landscape. We have over 40 million acres of land devoted to cultivated turfgrass in the U.S., and three-quarters of this is wrapped up in home lawns. Care and maintenance costs us $30 billion each year by industry estimates. That’s a lot of resources, which leads one to question whether lawns are eating more resources than they should. Let’s stack up the benefits. Here are ten things that lawns do for us and our environment:
- Stabilize soil against erosion from wind and water.
- Retain rainwater to recharge underground supplies.
- Filter dust and particulates from the air.
- Cool the air temperature by 7 to 14 F lowering energy costs in summer.
- Add organic matter to improve soil structure and water infiltration.
- Consume carbon dioxide and add oxygen to the atmosphere.
- Reduce the noise by absorbing sound.
- Decrease glare and heat transfer of reflected light.
- Increase safety in recreational use.
- Contribute to person’s well being.
Not so bad, right? So, it’s not a question of ‘should we have lawns,” but perhaps a question of “how much energy do we spend developing and maintaining a home lawn?” If you were to line up the dollar cost of lawn management from the highest to the lowest, it would be of no surprise that mowing is at the top of the list, followed by watering, fertilization and weed/pest control. Environmentally, you could keep this order the same in the cost of resources and impact on our lives. In California alone, 17 million gallons of gas is spilled filling mowers each year. How can we reduce these costs?
One approach would be to minimize lawn space and replace with ground covers and mulch. Especially in locations where maintenance is difficult or a safety issues (slopes), or cultural conditions make growing turfgrass difficult (under trees). In those cases, ground cover plants and mulch may be more desirable than a light-starved, sickly lawn.
In areas where turf lawns are desired, we can still reduce weed control, watering and fertilizing by wisely preparing, planting and maintaining the lawn. A healthy lawn with a good root system, mowed high, watered in the morning, fertilized sparingly in the spring and “fed” just before its high growth period (fall for fescue/bluegrass and early summer for zoysiagrass) will be more sustainable. Healthy lawns require less water, less pest control, less weed control and pay back all the benefits above. Mowing is the one thing we cannot get away from. Timely mowing is an advantage. Waiting too long to mow is as bad as scalping the lawn in attempts to lengthen the mowing frequency. Despite recent efforts to promote them, push mowers simply are not for everyone. But as gas prices go up, you might consider a battery mower. I have used one for 10 years on the same battery.
Watering seems pretty straightforward – the goal is to water in the morning, deeply (4 to 6 inches) and slowly so that the soil takes it up with less going down the street. In practice, because of varying soil types and saturation rates, this sometimes involves a more complicated schedule.
Fertilizers? To improve your sustainability quotient, stay away from step programs because they apply more that you need and include herbicides, insecticides and fungicides you may not need; try instead some slow-release forms so the nutrients are more easily absorbed by the lawn.
Lastly, if you have a problem, get help. Start with a soil test then go to the garden center or local experts for diagnosis. Don’t assume its grubs. Odds are it’s not. Sustainable lawns are possible without sacrificing the benefits. Make a move to improve your approach in 2008.