Is Your Lawn Dead or Just Parched?
Is Your Lawn Dead or Just Parched?
For much of Kentucky, the drought, heat and irrigation restrictions have been severe enough to seriously injure or kill many, many home lawns. Some people believe Kentucky bluegrass and tall fescue lawns will just become dormant or brown and then recover when cool nights and good rainfall return.
A.J. Powell, turf specialist for the University of Kentucky's College of Agriculture said unfortunately, this usually is not the case when the heat and drought is as severe as it recently has been in many parts of the Commonwealth.
"When lawns go completely brown, with little or no green leaves showing, you can expect kill or severe thinning of the grass," he said. "Kentucky bluegrass is more quickly injured than tall fescue but both grasses may die."
Although tall fescue is more heat and drought tolerant than Ky blue, usually it is growing on poorer soils and has few underground tillers to aid recovery. Also, because of the heat and humidity this summer, brown patch disease is an added stress on most tall fescue lawns.
Perennial ryegrass lawns seldom will survive such heat and drought, but bermudagrass and zoysiagrass lawns should have no problem. Fine fescue, growing in semi- shady locations,usually will become dormant and recover before the following spring.
Low maintenance lawns with a mixture of turfgrasses and weeds, and/or lawns rarely fertilized with nitrogen, usually will recover. They certainly won't get better, but you will not likely need to reseed.
Portions of a lawn with good soil, protected by moderate shade and north-facing slopes are more likely to survive. Very sandy and heavy clay lawns suffer the most damage.
It's important to remember that proper irrigation greatly will aid the lawn during very hot weather. However, if the lawn is over-watered and then suddenly the water is cut-off (during the heat and drought), that lawn usually is doomed. When this type of lawn turns brown, it is best to plan on reseeding.
"Unfortunately, someone can't look at the lawn or closely examine individual grass plants and positively determine if it is alive or dead," Powell said. " Even when a lawn does recover, it may be October or November before you can tell for sure how much turf has been lost and how bad renovation is needed."
It is obvious that hundreds of lawns throughout Kentucky will need renovation this fall. Powell offers some helpful considerations:
• Tall fescue is much easier to establish from seed than is Ky bluegrass. To get good establishment of Ky bluegrass, a conventional seedbed usually is necessary. Tall fescue can be established using a conventional seedbed or by slit (no-till) seeding.
• Timing is critical. The optimum timing for Kentucky is mid August through September, and no later than October 15. However, you should not consider seeding until a good, soaking rainfall has occurred and the drought officially is "over."
• The heat and drought greatly has increased the growth of crabgrass but a heavy crabgrass population usually is not a problem when renovating a lawn in the fall with tall fescue. The summer increase of perennial grassy weeds such as bermudagrass, nimblewill and dallisgrass is however, a serious problem. These need to be sprayed with RoundUp at least a few days prior to seeding; however you will not get good control of the perennial weeds unless the proper rate of RoundUp is applied and these grasses have enough soil moisture that they are actively growing.
• Especially for bermudagrass, spray as soon as soil moisture is adequate to get good growth, then wait about three to four weeks and spray again with RoundUp. Removing the dying sod a few days after the first spray will help encourage escaped, underground bermuda to re- grow; then the second spray will be more effective. With only one spray on bermuda, expect only 80 to 90 percent control.
Dense areas of living Ky bluegrass also will deter tall fescue establishment. To truly get a monostand of tall fescue and quality turf, thick areas of Ky bluegrass should be sprayed with Roundup a few days before renovation. If the lawn truly is devastated by the heat and drought, and perennial grassy weeds are not prevalent, you can omit the Roundup.
"Seed about five to six pounds of tall fescue per 1000 sq. ft. of lawn. If you're using a slit seeder, that slices through the thatch and drops the seed into the slits, apply about one pound of seed per 1000 sq. ft. for each pass," Powell said. "If you go over the lawn two times, then you also would want to broadcast about three pounds per 1000 sq ft before the last pass with the slit seeder. Just broadcasting the seed, without some surface disturbance / preparation, will result in almost no soil-seed contact and poor survival.
Traditional dethatching equipment can be rented at most rental agencies. With the knives set to penetrate through the thatch and about one-fourth inch into the soil, go over the lawn two or three times. Then broadcast the seed, and lightly go over the lawn again with the dethatcher.
Improved turf-type tall fescue varieties include: Jaguar 3, HoundogV, Guardian, Renegade, Rembrandt, Southern Choice, Falcon II, Crossfire II, Apache II, Genesis, Lancer, Marksman, Rebel Jr.,Pyramid, Pixie, Eldorado, etc. It is very important to regularly water the newly seeded lawn to keep the surface wet. If you cannot water and the weather remains dry, you will not have much success . If you can water two or three times a day, then you should have green turf beginning to show in about 10 days to two weeks.
You can apply the first Nitrogen fertilization prior to seeding but it is often better to wait until after germination. If nitrogen is applied at the time of seeding, it may force growth of weeds that compete with the young seedlings of fescue. Fertilizing immediately after germination gives the desirable grass an advantage.
The drought has taken a toll on Kentucky lawns, however, it will take a lot of rain and cool nights to tell whether they are dead or just parched.