Don Kinzler, Published September 06 2013
Growing Together: Emergency care key for stressed fall lawns
In reality, our yard looks like the aftermath of a prairie grass fire. The only greenery in my lawn right now is a scattering of dandelions and thistle, which seem quite content with the heat and drought that hit in July and August.
While growing up on the banks of Sheyenne River in Lisbon, N.D., we had plenty of free river water for irrigating flowers and vegetables. My fiscal upbringing did not include spending good money for “city water” let alone dumping it on the lawn.
September is a vital month for lawn care. It’s tempting to let the lawn slide into winter without extra fall chores, but lawn care now is actually more important than in the spring. Spring just seems more important because we’re all gung-ho for the smell of freshly mown grass.
Lawn grass is smart. It grows with gusto in spring when moisture is plentiful. If summer becomes hot and dry, grass preserves its energy by going dormant and brown. When moisture and cool temperatures return in late summer and fall, growth resumes and green grass grows merrily along.
But what if the dry spell doesn’t end, September rains don‘t come and lawns remain dormant?
Fall Lawn Care
During cool fall temperatures, grass plants focus on root growth. We can help our lawn become denser by encouraging this natural ability. Even if your lawn is green and active, September is a good time to power rake if thatch buildup is a problem, or core-aerate if the soil is hard and compacted.
Weed control is more successful in fall than in spring and summer. Perennial weeds like dandelions and thistle are now moving materials into their roots in preparation for winter, and they will carry your herbicide right along, resulting in better kill. An annual application of lawn weed herbicide in fall is better than in spring.
This is an opportune moment to caution about the overuse of lawn weed killers. There is no logical reason to apply herbicides four times a year, as is recommended by some chemical companies. A suspicious mind might question if their main business motive is something other than a homeowner’s welfare.
A September fertilizer application will help grass develop a stronger root system and a thicker turf by increasing lateral shoot growth. Types labeled “winterizer fertilizer” work well.
Mowing height should be maintained throughout fall at the recommended height of 2½ to 3 inches – same as summer. Although it’s a common practice to lower the mowing height in the fall, doing so can lead to winterkill in open winters with little insulating snow cover. It’s better to wait until early spring to give a low mowing before new growth begins.
Lawns will recover in the fall if they receive moisture and cooler temperatures. But if lawns remain stressed and brown, some fall practices can damage turf.
If the region doesn’t receive enough rain by mid-September to green up lawns, we should consider applying one to two inches of water per week.
When the grass resumes normal green growth, you can continue fall lawn care described above.
If you are unable to water, here are some tips for preserving drought-stressed lawns. Don’t aerate or power-rake until the lawn has recovered. Otherwise grass crowns can be torn, and the lawn may decline further.
Don’t spray herbicides on brown lawns which can cause additional stress. Herbicides don’t penetrate weeds toughened by drought effectively. Instead consider hand digging.
Fertilize only after the grass has greened. Nitrogen lawn fertilizers can further burn stressed grass plants.
Resist the urge to lower the mowing height to give the brown grass a fresher look. Instead raise the height to shade grass roots.
Seeding thin spots
Fall is the best time to repair thin areas of the lawn. Evaporation is lessened, making it easier to keep the seedbed moist. Seeding by Sept. 15 will allow grass to germinate, grow and get established before winter.
Areas in need of reseeding don’t need to be rototilled. Instead, use a garden rake or power-rake to remove excess thatch. Some stubble should remain, and a little soil should be visible. Sprinkle high-quality grass seed containing about 50 percent Bluegrass. Rake in, allowing some of the seed to remain visible. Water well initially and keep moist until germination.
The last half of summer has been a challenge in the Midwest. Remember the gardener’s optimism: Next year will be better, and as always, we’ll be Growing Together.
Don Kinzler, a lifelong gardener, worked as an NDSU Extension horticulturist and owned Kinzler’s Greenhouse in Fargo. Readers can reach him at firstname.lastname@example.org