Sun angle, day length, and overnight temperatures

In the last few days, summer has made a last ditch effort at a comeback. Before ceding completely to fall, the temperatures have climbed back into the upper 80’s. What is the difference between an upper 80’s day at the end of September versus July or August? It comes down to sun angles/incidence/intensity, day lengths, and overnight temperatures.

July and August are similar enough to generalize the two together as a summer day and compare that to September, which we will describe as a fall day. When we have a day in the upper 80’s to 90 degrees or hotter in the summer that sunlight is hitting our location on the planet at its most direct and its intensity is strongest. This means that the least amount of heat/light/energy is lost through reflection and absorption by the atmosphere. Therefore the suns energy is the most intense. When compared to fall, the suns energy is hitting at a steeper angle and more is impacted by the atmosphere and clouds. So while the temperature rises to a similar degree, it takes longer to achieve that number. Relating this to the golf course, the grass is subjected to less intense heat overall, but even when intensities are equal, it is for a shorter amount of time. So the grass plant has a sprint instead of a marathon. A few hours of warm temperatures are manageable.

The time factor is where day lengths become important. The sun rises later in the day and sets earlier. Therefore, the overall window the sun has to heat the turf is smaller. This heating time partially drives the amount of water lost from the soil and grass plants. If the sun starts heating later and ends earlier, immediately we know that there is less time for water to leave the system. So any water we apply overnight or early in the morning, will last later into the day. Similarly, as it starts to get darker earlier in the evening, the time the sun has to shine its brightest and most intense decreases. In the fall, the warmest part of the day is still near 3pm, but instead of having 4-5 more hours of daylight and intense sun, we now have only 2-4 hours, or less. Accordingly, if we monitor the turf between 1:30-4pm, applying any water as necessary, we can be more confident that water won’t be lost in the remaining daylight hours. In contrast, water applied at that time in summer, may be lost, or as the sun’s intensity continues, other areas may continue to lose more water.

Finally, and possibly most important, are overnight temperatures. In the summer, overnight “lows” can stay in the upper 70’s or even low 80’s. This is especially difficult on the greens. Generally, the turf can handle the heat stress of a hot day when it has a chance to recover overnight. When the temperatures are too warm the turf cannot adequately cool itself and recover from the stress of the day. Moreover, many of the disease issues we face are exacerbated by the warm overnights. The warmth and humidity are perfect for fungus and trouble for the turf. However, once we reach fall, the overnights temperatures start falling to more comfortable levels. The lower temperatures allow the plant to properly transpire and perform metabolic processes to heal and defend against all stress. Now, even when we have a warm day, the turfgrass plants are able to recuperate and prepare for the next day.

These are some of the keys to difference between summer and fall. By understanding these factors, the Grounds department is able to push the turfgrass a little harder so that the conditions of the course are ready for the busy golf calendar of the fall.

Etiquette Reminder of the Month

After filling your divot with sand, either on a tee or fairway, please smooth the sand pile out so our mowers don’t cut through the sand.

See you on the course!

Joe

jvillegas@bwrc.org

Native area maintenance

Our native areas have been an area of focus for the Grounds staff over the last several years. In order to return them more to native areas and less of wild areas, we have taken a few measures.

The last few years we have been slowly adjusting our native area maintenance program. The original concept for the native areas is discussed in more detail here. We have slowly increased the amount of inputs for the tall grass areas without converting them to regular rough and mowing them multiple times per week.

Our first step has been minimal chemical inputs to help control the most troublesome weeds. This past year we treated about 1/3 of the total native areas in order to clean up the most visible of spots. This is our second year of spring weed treatment and results have been promising. We have seen much higher concentrations of native grasses versus weed species and the aesthetics have improved. In addition, we will be making one more herbicide application this fall to help eliminate any weeds that survived the initial application and grew through the summer. This was not originally planned, but we have some product left over from spring from another program.

Our second, and most important, tool for maintaining the native areas is through mowing. Our goal has been to mow them 2-4 times per year. We are working on completing our second cut this week. We had hoped to get this mowing done back in August, but with construction, aeration, and regular maintenance, we were unable to make time. However, we are still accomplishing it early enough to allow for one more cut in late November or early December. A late summer and winter mowing help to injure and weaken some of the weeds by cutting off the crown of the plant. Even weeds that are not killed are severely stunted, and the grass, which handles the mowing much better, is given a competitive advantage over those weeds. Then, with the added herbicide application, we hope to really make progress against the weeds.

Sometimes native areas can be no-maintenance and sometimes they can be low-maintenance. We are working on making the native areas at Bretton Woods a little nicer and more aesthetically pleasing. To do this, we have to take a low-maintenance approach. With minimal time and labor inputs we have seen a slow transition to better grass areas.

Etiquette Reminder of the Month

After filling your divot with sand, either on a tee or fairway, please smooth the sand pile out so our mowers don’t cut through the sand.

See you on the course!

Joe

jvillegas@bwrc.org

Update on green surround rough

We continue to battle the rough grass around the greens so we added some new wrinkles to our approach this year. While our long term plan has shown progress, it is one area of the course that still really needs improvement.

The grass around the greens is a mix of several different species of grass: tall fescue, ryegrass, bluegrass (annual and Kentucky) and Bermuda grass. The ryegrass and bluegrasses do not handle the summer weather well and decline and die and bare spots result. Since there is not one cause of the poor performance of these grasses, this unfortunately means there is not one solution either. Weather, soil, grass species, traffic stress, and more all contribute to the problem.

This summer was not as hot or as long as previous years, so as a result the grass was not as decimated. Some of our strategies also helped the grass survive. First, for several years (read a 2015 post here) we have been over-seeding the green surrounds with tall fescue. Tall fescue is the most drought and heat tolerant of the grass species available to us. It is easily grown from seed and we have a very good seeding machine to use. We have already done this once and we will do it again in the fall. Continually pouring more desirable species into the green surrounds will continue to lower the percentage of unwanted species and lead to less collapse.

Last year we instituted a hand-watering program specifically aimed at the rough around the greens. We saw tremendous benefit and so we continued, and increased it this year. Hand-watering the green surrounds consists of exactly what it sounds: we send 2-4 staff members with hoses to hand water the rough around the greens, from the collar out 15 feet. There is more information on the process as well as some of the reasoning behind it here.  We again saw huge benefits and it will be a staple of our maintenance program going forward.

We also tested 2 different chemicals this year designed to help the soil retain moisture. We sprayed them specifically on the rough around the greens. We saw improved water retention from both, as well as a clear favorite to continue to use next year. Although too much water can be just as bad (or worse) for turf, this ability to hold and retain more water was helpful for the rough. More water holding capacity of the soil means that our hand watering and irrigation are used more effectively. Having more water available to the plant during the heat, when we are between rain storms or irrigation schedules, helps more plants survive. With additional hand watering and the sprinkler adjustments we have made in the past (more information on that here), this new chemical makes maintaining adequate soil moisture easier and improved turf health resulted.

We don’t intend to minimize the problem or imply it is corrected. This is something we continue to work on improving. Although any turf loss is frustrating, improvements have been made. Some of the problems are issues we can resolve and some are weather related that will always be present, but we do constantly make adjustments to get better results.

Etiquette Reminder of the Month

After filling your divot with sand, either on a tee or fairway, please smooth the sand pile out so our mowers don’t cut through the sand.

See you on the course!

Joe

jvillegas@bwrc.org

Soccer field maintenance

August is a time to do a little catch up. We aerate greens, tees, and fairways. We apply our compost to the Bermuda grass. In general, we are trying to relieve the turf from a long summer of stress and prepare it for a productive fall. We apply the same concept to the soccer field.

Since we built (rebuilt) the second soccer field, we have been able to close the upper soccer field for 3-4 weeks in August to attend to much needed maintenance without having to work around regular use. By closing the field, we are able to take all of the traffic off of the upper field, redirect it to the lower field, and give the turf on upper field a much needed break.

For this month of closure we perform several cultural practices. First, we aerate the field. This is similar to the process we do on the fairways, but in this instance we don’t pull any material out of the field. At the end of a long summer, the roots of the turf are so weak that if we try and pull a core, most of the field pulls right up with it. So we simply poke a hole instead. Following aeration, we apply the same compost as on the Bermuda grass. Next, we topdress the entire field with sand. For the last few years, we have been lucky enough to have old bunker sand available to use as top dressing material. We spread this on very generously, especially down the center of the field. Once the compost and sand are applied, we drag. Dragging helps to redistribute the sand and compost down into the holes created from aeration. It also moves material from high areas to low areas to help level the entire surface. Our last step is to seed the field.

Each spring we seed the field to start the season. The field is at its strongest right after this seeding, as the weather warms up, and the turf really starts to grow. Think of how thick, green, and healthy the rough is on the golf course; that is the equivalent of the soccer field. As spring turns to summer, after many matches and soccer camp use the field, and the heat turns up, the field slowly declines; again, compare it to the rough on the golf course towards the end of summer. Our resources are most often outmatched by these factors and we keep the field respectable, but it is not World Cup quality. So, come August, after the long summer, it is time to seed again. We seed 3 to 4 times, all in different directions, to incorporate as much new grass as possible.

Our last step is to lay new sod in some of the areas that are too damaged for even the seed to repair. Usually they are always the same areas: both goal mouths, center field, as well as a few low areas that always puddle. We level out the low areas, lay new sod, and then fertilize the whole field.

Ideally, we accomplish all of these steps in the first 7-10 days that the field is closed, and use the remainder of the time to let everything grow and heal so that the new turf is as mature as possible once we reopen.

By the time we reopen the field, the weather has usually retreated from its July/August peak and the turf is not subjected to the same stresses. The new seed thickens and the field is ready for a busy fall season.

Etiquette Reminder of the Month

After filling your divot with sand, either on a tee or fairway, please smooth the sand pile out so our mowers don’t cut through the sand.

See you on the course!

Joe

jvillegas@bwrc.org