PPDL Picture of the Week for
September 14, 2015
Drought-Stressed Turf: What Can You
John Orick, Purdue Master Gardener State Coordinator, Department of Horticulture and Landscape Architecture
This is the time of year when many turf managers and homeowners notice the effects of high temperatures and low rainfall on turf areas. Turfgrasses go dormant when the need for water in the plant exceeds the amount of water available for plant uptake. Dormancy is a mechanism by which the leaves turn brown and die, but the crown (or growing point) and the root system remain alive to help plants survive dry conditions. This dormancy mechanism is utilized by Kentucky bluegrass, which is our most common lawn grass in Indiana.
Turfgrass plants lose water through the leaves through a process called transpiration and from the soil through evaporation. Combined these two mechanisms of water loss are termed evapotranspiration. Dead leaves lose less water than leaves that are green and growing. So, this helps conserve water in the crown of the plant. Turfgrass plants survive dormancy and drought because of the conservation of water in the crown, important solutes and enzymes in the plant that protect the cells, availability of carbohydrate reserves for regrowth, and extensive underground rhizomes or root systems to sustain the plant. So, brown turf observed during hot, dry periods is not necessarily dead, it is most likely dormant. Most turfgrass plants can survive about 4-6 weeks of dormancy before plants begin to die. After 4-6 weeks of dormancy, turf areas can be irrigated with 1 – 1.5 inches of water every 4-6 weeks to prevent significant turf loss. This minimal amount of irrigation will only help to prevent significant turf loss and will not cause the turf to return to normal growth and color. Once regular rainfall returns, it could take 4 weeks or more for plants to return to a normal growth rate and color.
Here are some other important tips for managing drought-stressed turf:
Avoid mowing dormant turf areas unless there is new growth as a result of rainfall or irrigation. Mowing or even moderate foot traffic can cause damage to weakened turf areas.
If tall weeds cause an aesthetic problem in turf areas, consider using a push mower or weed trimmer to just clip the tops of weeds and not mow dormant turf.
If regular rainfall returns in the fall and normal growth is observed, consider applying a turf fertilizer to help weakened plants recover. A fertilizer application in September, October, or November will help turfgrass plants grow deeper roots and store carbohydrates for later growth.
Avoid broadleaf weed control applications to drought-stressed or dormant turf.
Once rainfall returns, if damaged areas are larger than the size of your hand, consider reseeding those areas. Plant resilient turf species like tall fescue or Kentucky bluegrass which both survive dry periods well.
Your Lawn in Times of Drought:https://www.youtube.com/watch?v=wS8UnMzwbMY
Recovery of your Lawn after a Stressful Summer:https://www.youtube.com/watch?v=hXZMfCVW0os
Related Articles and Publications:
Irrigation Practices for Homelawns (AY-7-W)https://www.extension.purdue.edu/extmedia/AY/AY-7-W.pdf
Streaking Across the Lawn??? P&PDL Picture of the Week for July 25, 2005https://www.ppdl.purdue.edu/PPDL/weeklypics/7-25-05.html
My Lawn is Brown and Crunchy… Is it Dead? What do I do now? http://purdueturftips.blogspot.com/2012/06/my-lawn-is-brown-and-crunchy-is-it-dead.html
Lawns and the Summer 2012 Drought/Heat Crisis: Now What?https://turf.purdue.edu/pubs/082012_DroughtPublication.pdf
Lawn Improvement Programs (AY-13-W)https://www.extension.purdue.edu/extmedia/AY/AY-13-W.pdf