Frozen Turf

By Dr. Leon LucasPlay is often delayed on courses during the winter due to frost on golf greens. The reason the club should not allow play on greens that are covered with frost is that the turf will be damaged from walking on the frost. The ice crystals in the frost can puncture the leaves from foot pressure. The damage will appear as footprints later in the day and will be present until the turfgrass grows out of the damage. The damage may be evident for several months and result in weaker turf in the spring in the area around where the hole was on the day frost was present.
If the frost remains longest on the first few greens, the opening of the course may be delayed longer than if the frost is on the back nine greens. Some clubs change the starting holes in the winter to reduce the delays. The superintendent can apply a small amount of water to help remove the frost if the air temperature is not too cold. Running fans to blow air over the greens (the same fans used in the summer) will help to reduce frost problems if the temperature is only a few degrees below freezing. Greens with shade in the morning have lower soil temperatures and usually have the most frost on the grass. The removal of the trees that are shading the greens will help to reduce the delays from frost.
Deciding when to allow play on greens with frozen soil is more difficult to determine. The greatest damage occurs to the turf when the top layer of soil thaws while a frozen layer remains deeper in the soil. The thawed layer will be saturated with water and becomes spongy. Walking on turf with this condition will cause foot printing and can cause the surface of the green to become uneven. Severe turf damage can result from shearing off the roots as the turf moves above the frozen layer. This damage in areas around where the hole is located on these days will appear as weaker turf later in the year.
It is difficult to explain to golfers that they should not play on greens that are thawing during a warm and sunny day following very cold weather. Golfers are eager to return to the course on the nice days following long periods of cold weather. All greens usually do not thaw at the same time. Shaded greens are the last to thaw and more damage often occurs on these greens because it is difficult to keep golfers off the course any longer.