Posted by: Michael Boyes, Senior Consultant Agronomist – Sustainability & Environmental Management
As winter approaches, and cold, dark mornings close-in, the inevitable threat of frost delays returns to golf courses. This remains one of the most contentious issues for any golf course manager, who is in constant discussions with the greens committee and members to deliver longevity of playing surfaces whilst tackling the unavoidable curveballs that nature throws our way.
Decisions taken in response to these curveballs will always consider commercial factors, but we must be under no illusion about the effect that foot and vehicular traffic has on turf health during periods of frost.
What is frost?
In simple terms, frost is frozen dew in which ice crystals have developed on the outside of the plant. 75-80% of a blade of grass is water, leaving the inside of the plant susceptible to freezing. Turf, which is normally quite resilient to traffic, becomes brittle and vulnerable to damage as the frozen plant cells rupture and are unable to repair themselves. Although the visual signs of damage are often not immediately obvious, they can appear in the following days and take months to repair.
Cold, clear nights result in a loss of surface heat, meaning that the turf can freeze even with an air temperature above zero. This is known as radiation frost and can result in leaves freezing even when the soil doesn’t. This frost will lift relatively quickly.
Why do we need to protect the greens?
While frost can appear on every square foot of the golf course, closely mown areas are the most susceptible to damage. This is because there is less leaf area to resist the impact on the turf on a surface which suffers the most concentrated levels of traffic during routine play. A typical foursome takes 300 steps or more on each green, each of which can cause damage to the plant under frosty conditions and damage to the soil structure as it thaws. Prolonged periods of heavy frost can lead to significant damage if frozen grounds prevent the repositioning of the hole cup, with prolonged intensive play leading to a doughnut of wear around the hole.
Protecting the grass sward from damage is of upmost importance in greens with fine grass species such as Fescue and bentgrasses. These are less tolerant to physical disturbance than others, with the weakening of sward potentially opening up gaps for poorer species to invade such as annual meadow-grass.
Who decides when the course is shut for frost and more importantly re-open for play?
The Course Manager is the appointed turf expert and has the expertise to fully appreciate the micro-climates which exist across the site. Most importantly, the course manager can apply the expertise to the course and conditions, for instance that the north-facing slopes and low-lying, sheltered and shaded areas will continue to be impacted by frost, long after other areas may have thawed significantly.
How do we reduce the impact of frost?
It is worthwhile considering the development of temporary greens (located sufficiently away from the actual greens) and the possible re-routing of play to avoid those putting surfaces which traditionally remain frozen for the longest. This could permit the re-opening of the course before the frost has dissipated across the site completely.
Temporary greens were a commonly used method of protection in decades past, but warmer winters and an expectation of year-round play has seen reductions in the widespread use of temporary greens. Club committees are under increasing pressure to keep greens open.
It is also important to undertake appropriate thinning and removal of woodland around key playing areas (i.e., greens and tees) to improve the general growing environment with increased light penetration and air circulation. Persistent shade increases the influence of frost by preventing sunlight from melting the ice crystals, which is particularly problematic if affects those holes which are earlier in the round.
How do we manage course closure for frost?
- Adopt a detailed and formal Frost Policy as part of your Course Policy Document, which is specific to your course and communicate the procedures associated with the policy consistently through all available channels (i.e. signage, website updates, members’ newsletters, tee sheet notes and social media). In the first instance this should commence two-weeks before frost is typically evident on your site and then be retained year-on-year.
- Ensure that all interested parties are aware that one person (Course Manager), is responsible for closing the course for a frost delay and duly authorised to decide when the closure is lifted, and play can recommence.
- Allow sufficient time for the maintenance crew to undertake the essential course set-up operations, as the golfers will inevitably expect to commence play as soon as the frost has gone.
With the correct level of information and communication, we can assure the conscientious golfer that frost delays are not designed to frustrate but intended more as a means of protecting the greens to avoid unnecessary damage and promote longevity of the surfaces to extend the playing season as much as possible. As turf grass professionals, we want to the golfers to have the best playing surfaces we can produce all year round, and we need help and understanding to work with nature towards this mutual aim.