FROST AND THE IMPORTANCE OF FROST DELAYS: LET’S PRESERVE QUALITY.
A delay in the opening time of a golf course is a serious issue a greenkeeper can face during the winter and early spring. Temporarily closing the course until the ice melts, avoids considerable damage to it, but it is something that angers golfers year after year, and it is necessary to raise awareness on this topic to preserve the quality of our courses and enjoy quality golf.
This article aims to report on the main causes that motivate the closure of a golf course when it is frozen, and to provide with ideas to get golfers going as soon as possible.
Why the golf course freezes?
Common frosts (radiation) occur during cold and clear nights, when the plant transfers heat to the atmosphere (radiation heat). While the plant suffers heat losses at night, the leaves temperature drops to a point in which is colder than the air temperature. It is then when water vapour present in the atmosphere condenses on the leave. If the leave temperature continues dropping, the water freezing point may be reached, so that the condensed water vapour on the leave turns into ice. This can even occur when the air temperature is higher than the water freezing point, because the critical factor for turf frost, is the existing temperature of the leaves, and not the one of the atmosphere. For example, when the air temperature is 1 or 2ºC, and the leave temperature is 0ºC, the condensed water vapour on the leave freezes.
The probability of frost decreases during overcast nights, due to the screen effect produced by clouds. At night, plants suffer heat losses due to radiation, but clouds are able to refract “absorb” and irradiate back the heat (infrared radiation) towards the turf, therefore the plant ends up not suffering great heat losses. Also, it is not likely that frost occur during windy nights. The wind promotes air circulation and makes possible the exchange of the air layer near the turf with higher ones, and consequently impedes water vapour condensation. Therefore, flatter areas have less probability to frost than slopy areas, where the air can be more easily exchanged.
In regions with Mediterranean climate (soft minimum temperatures), the frost occurs at the end of the night, just before sunrise, because the plant has been radiating heat all night. It is then when the leaves have the lowest temperature since the night begun, and coincidently, it is when the golf course should be ready for play. Frost may extend a few hours after sunrise because the solar radiation angle is low at that time, and it does not provide the plant with sufficient energy to heat up the plant.
Advection frosts may also occur when cold air blows into an area to replace warmer air that was present before the weather changed, and drops the temperature down to the water freezing point. This type of frost is associated with cloudy conditions, moderate to strong winds, no temperature inversion and low humidity.
Why ice causes problems to play golf?
The ice itself does not cause damage during normal cold weather conditions. The biggest damage happens when there is traffic over frosty areas. When temperatures drop below 0ºC, frost not only occur outside the leave, but also at a cell level. We shall remind that more than a 90% of the leave is made of water, therefore, if water freezes, the leave too. Initially, the ice forms outside the cells, but when frost happens inside the cell, ice crystals are formed in them, and the damage can only be produced by mechanical breakup of the cell structure. So that, when we walk over frozen turf, every footstep literally breaks down plant cells, causing the death of the cell tissue.
It is difficult to understand that simply walking over a green, can cause such damage, especially when this damage will be visible after 48-72 hours in the form of brown-purplish marks, or footsteps in our case. Considering that a fourball tees off, and that one single golfer can make 60 steps in each green, every game can leave approximately 4.320 footsteps in the greens of the golf course. This is a potential big problem for the golf course and must be prevented. Also, it needs to be explained to the members.
The damage becomes huge when produced by buggies or maintenance machinery. This is why no activity should take place in the golf course until the ice melts.
How can we avoid the impact of frost?
It is not easy to avoid the consequences of adverse weather conditions, such as frost in a golf course. However, it is possible to carry out various measures that will reduce the duration of the frost.
An essential measure is to promote air circulation and access to sunlight. Carrying out landscaping works can be very beneficial because not only allows to reduce shading, but also promote air circulation through the course.
Turf covers are a good tool to prevent from frost. The use of them is usually limited to critical areas because of the time it takes for their installation and removal.
Light irrigation can reduce the duration of the frost. It is necessary to carry it out when the air temperature rises over 2-3ºC, and that excess irrigation could lead to soft ground conditions.
Thank you for being understanding.
Frost damage in a golf green is not simply matter of aesthetics. The quality of the green will be affected until the necessary measures to fix it are carried out, or enough time goes by for the damaged area to recover. There are numerous actions that we golfers know help contribute keeping up quality in our golf course, such as repairing pitchmarks, repair divots, etc. Being understanding and patient when there is a delay due to frost, is an action that makes us better golfers. By embracing this attitude, we help the greenkeeping team to achieve their goal, which is to deliver the best possible course quality standards, and the ones that we expect to find.
Luis Cornejo Hermosín, MD and founder of Surtec Golf Agronomy. MSc Sports surface technology by Cranfield University.