Managing Turfgrass under Heat Stress

Throughout Virginia, cool season turfgrasses experience problems associated with summer heat stress. Typically, heat stress is most acute on turfgrasses under conditions depicted by extremely high temperatures and humidity levels that persist for several months. The summer heat with high humid conditions comes with stress on how to keep grass intact and endure the harsh weather conditions. Turfgrass becomes more vulnerable to both biological and mechanical damage that accompanies the hot season.

The Virginia Extremes

According to Virginia‘s weather reports, daytime temperatures move up to 90 degrees and 70 degrees during the night. During this warm season, artificial turf fields are considered unsuitable for play since field surface temperatures levels during the day usually reach up to 150o F; levels that pose safety concerns to field users.

Sustained heat stress greatly increases soil temperatures; thus, affecting root health, growth and function. Less damage is experienced to the roots during high spring temperatures since the soil temperature is usually cool. However, as summer reaches, the night temperatures become less cooling on the soil, resulting in a significant soil temperature rise.

High soil temperatures cause reduced root production, minimal new roots production, faster maturation and die back of the roots. Eventually, the turf thins and become more spindly.

Measures Taken to Curb Heat Stress

Managing Special Events on Turfgrass (2)

It is indeed a challenge to maintain turfgrass under heat stress.However, that does not mean that it can’t be managed. The following tips are associated with alleviating most of the problems that accompany excessive heat:

  1. Mowing heights: For the warm season, cut the grass to 1.5 to 2 inches. Taller mowed turf typically thrives compared to grasses cut at heights that are ideal only in optimal growth periods. Interchange mowing practice and rolling out greens with consideration to skipping a day if the schedule of play allows.
  2. Watering modes: Watering to supply enough soil moisture, but avoid over-irrigating since the saturated soil will result in rapid weakening of the turfgrass. With more rain during early summer, water 1 to 1.5 inches per week taking two different days. If the turf shows stress due to lack of water, field managers should water the entire green using the overhead sprinklers.
  3. Aerify using smaller tines: A superintended should use smaller tines when gasifying if the putting surface is sealed since the ones with larger diameters may penetrate deeply removing even parts of a soil core.
  4. Little amounts of fertilizer: Small doses of fertilizer should be applied with observation being done before fertilizing again.
  5. Monitoring traffic patterns to minimize stress on the turfgrass.
  6. Mower Selection. During the heat stress period, managers need to consider switching from a triplex unit to a walking greens mower or a solid roller to minimize wear stress when recovery of shoot growth is compromised by heat stress.

Better turfgrass during summer

From golf owners to superintends, it should be known that maintaining turfgrass during summer is still a challenge. Common practices like mowing and irrigation either before or during summer make turf perform better.

Irregular irrigation during spring gives room for roots to grow and preparation is also brought for the summer by leveling cooling process. When the weather is hot, irrigating frequently and light is essential since transpiration is high. What is prohibited is over-irrigation. Moderating the counter on some of the effects of hot weather, keeping the right measures will see the turf become healthy to survive the summer season.