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Maintenance activities are underway at nearly every golf course across the country. However, many superintendents are being forced to maintain golf courses with only a handful of staff due to the spread of COVID-19. To put things in perspective, it’s not uncommon for an average 18-hole golf course to have between 12 and 15 employees dedicated to course maintenance tasks during the season. With a dramatic reduction in available labor, completing routine cultural practices can be a real challenge and superintendents will have to prioritize maintenance activities. This article answers some frequently asked questions about reduced golf course maintenance during COVID-19.

 

How high can I raise mowing heights for greens, tees and fairways without causing issues down the road?

Raising the height of cut on putting greens, tees and fairways can extend the interval between mowing events. However, if the turf grows too tall, playing conditions will deteriorate and restoring normal playability quickly will be difficult. The highest possible height of cut for each primary playing surface is different for each course. The maximum recommended heights of cut for key playing surfaces are approximately:

Putting greens – 0.187 inch

Fairways, approaches and tees – 0.75 to 1 inch  

Again, these are basic guidelines. One way to determine the maximum height of cut that is most appropriate for the fine turf areas at your course is to think about it in terms of percentages. For fine turf areas, it would be prudent to only raise the normal mowing height by 20% to 30%. Raising the mowing height by more than 30% will likely require a gradual reduction over several weeks to resume mowing at your typical mowing heights without scalping and turf damage.

 

How can I use plant growth regulators to best suppress growth and reduce mowing requirements?

Plant growth regulators (PGRs) are valuable tools to reduce the growth rate of turf and necessary frequency of mowing. To maximize their effectiveness, apply PGRs based on accumulated growing degree days (GDDs). The article “Managing Growth Rate During COVID-19” is a great resource that discusses the ideal reapplication intervals for the most commonly used PGRs. Applying PGRs at high label rates, shorter-than-recommended GDD intervals, or tank-mixing multiple products together can offer increased growth suppression compared to traditional PGR programs. However, it’s difficult to predict if PGRs, even when applied with the various strategies just mentioned, will consistently allow putting greens to be left unmown for longer than three days and tees and fairways for longer than seven days.

With a small maintenance staff, applying PGRs more frequently than normal or to playing surfaces outside of greens might prove to be difficult. It’s also important to remember that a rebound effect – e.g., an increased clipping yield of approximately 20% – can occur if a PGR isn’t applied within the product-specific GDD interval. Plant growth regulators can help to manage turf growth rates, but they need to be applied carefully and should be viewed as one of many tools to help manage turf growth.

 

How much can I scale back my nitrogen fertility program without causing problems later in the season?

Nitrogen fertility inputs should always match the recovery demands from traffic and the need to maintain a dense stand of turf. If golfer traffic is significantly lower on your course, nitrogen inputs should be reduced proportionally. On putting greens, reducing nitrogen inputs by 15% to 25% will help to carefully manage growth rates without significant concern of long-term impacts. Fairways and rough are the largest maintained turfgrass areas on a course, so scaling back nitrogen inputs in these areas by 50% or more will prove to be valuable because it will translate into a longer interval between time-consuming mowing events. Monitoring the growth rate and clipping volume is always valuable, especially now as management inputs are geared toward reducing the need to mow turf.

 

How should I prioritize mowing of different rough areas?

Rough is generally the largest maintained turf area on a course, so these areas take the longest to mow. Scaling-back rough mowing frequency is recommended, but not necessarily in all areas given the potential impact on play. The green surrounds are the most important rough areas while tee surrounds are typically the least important. As a result, the mowing interval for these areas should be different. A green surround should be mown every seven to 10 days while a tee surround could probably be mown every 14 days without causing playability issues.

The primary rough around the fairways can be mown in the range of every 10 to 14 days to save labor resources. Installing a graduated rough system, where the mower operator makes a few passes around the fairway more regularly – e.g., the area approximately 15 to 20 feet from the edge of the fairway – makes sense given the labor challenges many courses are facing. The first cut of graduated rough could be mown every seven to 10 days while the rest of the rough could be mown on a longer interval, perhaps every 14 to 21 days depending upon the turf growth rate.

Raising the mowing height will make it easier to increase the mowing interval for rough. However, a higher mowing height will likely yield pace-of-play challenges and more difficult playing conditions. Unfortunately, these issues may be something that can’t be avoided in the short term.

 

What is the biggest priority for managing weeds, diseases and insects?

Plant protectant application timing is critical for controlling weeds, diseases and insects. Smaller staff sizes will make it more challenging to apply these materials at the critical times. Suppressing diseases and insects should take precedence over controlling weeds if you’re forced to make these types of decisions. Summer grassy weeds such as crabgrass, goosegrass and sedges are unsightly and can compromise playing conditions, but there are some options for correcting these issues later on and weeds are typically not as destructive as diseases and insects. That said, making at least one preemergence application for summer annual grassy weeds will be much more effective than postemergence applications later on in the season.

 

Conclusions

One of the most challenging parts of maintaining a golf course during the COVID-19 pandemic is staying focused on keeping golf course turf healthy rather than focusing on playability. Under normal circumstances, playing conditions and turf health are equally important; but we’re in unprecedented times so the focus needs to be adjusted. Contact a regional USGA agronomist to get detailed, customized guidance specific to your course.

How high can I raise mowing heights for greens, tees and fairways without causing issues down the road?

 

Raising the height of cut on putting greens, tees and fairways can extend the interval between mowing events. However, if the turf grows too tall, playing conditions will deteriorate and restoring normal playability quickly will be difficult. The highest possible height of cut for each primary playing surface is different for each course. The maximum recommended heights of cut for key playing surfaces are approximately:

 

Putting greens – 0.187 inch

Fairways, approaches and tees – 0.75 to 1 inch  

 

Again, these are basic guidelines. One way to determine the maximum height of cut that is most appropriate for the fine turf areas at your course is to think about it in terms of percentages. For fine turf areas, it would be prudent to only raise the normal mowing height by 20% to 30%. Raising the mowing height by more than 30% will likely require a gradual reduction over several weeks to resume mowing at your typical mowing heights without scalping and turf damage.

 

How can I use plant growth regulators to best suppress growth and reduce mowing requirements?

 

Plant growth regulators (PGRs) are valuable tools to reduce the growth rate of turf and necessary frequency of mowing. To maximize their effectiveness, apply PGRs based on accumulated growing degree days (GDDs). The article “Managing Growth Rate During COVID-19” is a great resource that discusses the ideal reapplication intervals for the most commonly used PGRs. Applying PGRs at high label rates, shorter-than-recommended GDD intervals, or tank-mixing multiple products together can offer increased growth suppression compared to traditional PGR programs. However, it’s difficult to predict if PGRs, even when applied with the various strategies just mentioned, will consistently allow putting greens to be left unmown for longer than three days and tees and fairways for longer than seven days.

 

 

 

With a small maintenance staff, applying PGRs more frequently than normal or to playing surfaces outside of greens might prove to be difficult. It’s also important to remember that a rebound effect – e.g., an increased clipping yield of approximately 20% – can occur if a PGR isn’t applied within the product-specific GDD interval. Plant growth regulators can help to manage turf growth rates, but they need to be applied carefully and should be viewed as one of many tools to help manage turf growth.

 

How much can I scale back my nitrogen fertility program without causing problems later in the season?

 

Nitrogen fertility inputs should always match the recovery demands from traffic and the need to maintain a dense stand of turf. If golfer traffic is significantly lower on your course, nitrogen inputs should be reduced proportionally. On putting greens, reducing nitrogen inputs by 15% to 25% will help to carefully manage growth rates without significant concern of long-term impacts. Fairways and rough are the largest maintained turfgrass areas on a course, so scaling back nitrogen inputs in these areas by 50% or more will prove to be valuable because it will translate into a longer interval between time-consuming mowing events. Monitoring the growth rate and clipping volume is always valuable, especially now as management inputs are geared toward reducing the need to mow turf.

 

How should I prioritize mowing of different rough areas?

 

Rough is generally the largest maintained turf area on a course, so these areas take the longest to mow. Scaling-back rough mowing frequency is recommended, but not necessarily in all areas given the potential impact on play. The green surrounds are the most important rough areas while tee surrounds are typically the least important. As a result, the mowing interval for these areas should be different. A green surround should be mown every seven to 10 days while a tee surround could probably be mown every 14 days without causing playability issues.

 

The primary rough around the fairways can be mown in the range of every 10 to 14 days to save labor resources. Installing a graduated rough system, where the mower operator makes a few passes around the fairway more regularly – e.g., the area approximately 15 to 20 feet from the edge of the fairway – makes sense given the labor challenges many courses are facing. The first cut of graduated rough could be mown every seven to 10 days while the rest of the rough could be mown on a longer interval, perhaps every 14 to 21 days depending upon the turf growth rate.

 

Raising the mowing height will make it easier to increase the mowing interval for rough. However, a higher mowing height will likely yield pace-of-play challenges and more difficult playing conditions. Unfortunately, these issues may be something that can’t be avoided in the short term.

 

What is the biggest priority for managing weeds, diseases and insects?

 

Plant protectant application timing is critical for controlling weeds, diseases and insects. Smaller staff sizes will make it more challenging to apply these materials at the critical times. Suppressing diseases and insects should take precedence over controlling weeds if you’re forced to make these types of decisions. Summer grassy weeds such as crabgrass, goosegrass and sedges are unsightly and can compromise playing conditions, but there are some options for correcting these issues later on and weeds are typically not as destructive as diseases and insects. That said, making at least one preemergence application for summer annual grassy weeds will be much more effective than postemergence applications later on in the season.

 

Conclusions

 

One of the most challenging parts of maintaining a golf course during the COVID-19 pandemic is staying focused on keeping golf course turf healthy rather than focusing on playability. Under normal circumstances, playing conditions and turf health are equally important; but we’re in unprecedented times so the focus needs to be adjusted. Contact a regional USGA agronomist to get detailed, customized guidance specific to your course.