August 11, 2016
Summer Lawn Care
Last week I talked about how to efficiently water your lawn in the summer without overwatering. There was an important point I needed to explain a little more. Someone asked what I meant about letting a lawn go dormant in the hot summer months and why it applied to bluegrass lawns, but not fescue lawns.
Dormancy is when a lawn turns brown and puts on little or no new above ground growth, but the crown and roots remain alive. The turf will resume normal growth with adequate moisture when cooler temperatures return. If you let your lawn go dormant, you still need a minimal amount of water, maybe a half inch of water every two weeks through precipitation or irrigation, to keep the crown and roots alive.
Bluegrass lawns can go dormant and still recover when cooler temperature and adequate moisture are present. This usually happens sometime in September. However, fescue turf does not respond the same. You can reduce the amount of water applied, but it needs to be watered enough to keep it green. If areas in fescue turns brown from lack of water, it enters a state of “permanent dormancy” (read: it’s dead) and you will need to reseed these areas.
Another lawn “no-no” during the summer is to fertilize a lawn, thinking you will help it green up. Fertilizer will trigger top growth and a higher demand for moisture and nutrients from a compromised root system. Fertilizing during the summer will do more damage than good on most home lawns because it creates more stress on the root system, making it weaker and more susceptible to insect and disease damage. The only exception would be on very highly managed lawns where a lush turf is required throughout the growing season. On most lawns, avoid fertilizing in June, July and August.
Next to properly watering your lawn, the second most important thing to keeping it healthy in the heat of summer is proper mowing management. Frequently sharpen your blade so you are cutting, rather than tearing, the leaf blades. Look at the tips of the leaf blades after mowing. There should be a clean, smooth cut. It the leaf tips look fuzzy or ragged, sharpen your mower blade.
The other thing you should do when mowing is, if it isn’t already at the uppermost setting, raise your mower height. Mine never leaves the highest setting year round, but it is most critical in the summer. Cutting higher helps shade the soil, keeping it cooler and reducing the amount of moisture evaporating from the soil surface. This leaves more moisture in the soil for the plant to use.
One complaint I hear about mowing higher is the need to mow more frequently. Actually the opposite is true. To minimize stressing the lawn when you mow, you should remove no more than a fourth of the total height when you mow. So, if you set your mower height at three inches, that means you can let it grow an inch, to four inches, before needing to mow again. However, if you want to keep that neat, close-mowed look and set your mower height at one and a half inches, that means you can only let it grow a half inch to remove a fourth of the blade height before you need to mow again.
The absolute worst thing you can do for your lawn is to set your mower height at one and a half inches, then let the lawn grow to three inches or more before mowing, thinking the taller height is benefitting the turf. The height is beneficial... until you mow it back at one and a half inches and remove half or more of the total blade height. Now I’m sure none of you do that, but you might have a neighbor who does.
These are the same people who complain about extremely high water bills because of how much they have to water their lawn to keep it alive. Also, they are experts at overseeding their lawn to fill in areas where the turf dies out, year after year. I’ll let you draw your own conclusions from that!
For more information on summer lawn care, go to the UNL turf website at http://turf.unl.edu or contact your local Nebraska Extension office.