We study these temperatures because they help us know why the grass might be reacting the way it is. This season the grass has been slower to begin to grow and we now know why. The 27 nights of temperatures below freezing have a larger effect than the lack of days over 70 because the cooler temperatures at night effect the soil temperature more. As we have learned in the past the soil temperature determines the turf growth more than the air temperature. Our cool and warm season grasses prefer a soil temperature of at least 50 degrees. With multiple nights of temperature in the teens the soil temperature did not have any way of warming up enough to begin that growing process. One or two nights of extremely cold temperatures is not as harmful, however the fact we have had 27 so far can explain why there has been some delay on growth on certain fields.

Our warm-season fields are much more susceptible to winter damage due to cold weather so we cover them with turf blankets through the winter. The turf blankets not only protect the turfgrasses from the frigid temperatures outside, but also hold in heat and moisture so the grass can continue to receive nutrients even in colder conditions. We also cover our stadium field to protect is as much as possible since it is used by the Washington Spirit and this year, hosted an early match between DC United and the Houston Dynamo. When the turf blankets were lifted a few weeks ago on the bermudagrass fields, there was steam coming from the ground because it was so warm under the covers compared to the air, which just goes to show, how effective the turf blankets really are. Also if you compare how far along the stadium field is with other cool season fields, you can see how much growth the turf blankets can help produce.

Going forward we are crossing our fingers for some more predictable and consistent weather patterns!