Conditions Due to Conditions

With July being the hottest month of the year, turf stress is common.  However, this past month was particularly memorable--and not in a good way.  For the month of July, 27 out of 31 days were at, or above the average temperature, with only four days being below the average high.  Rainfall was also excessive, totaling 8.10", which is 67% above average.

There are countless reasons why turf can struggle, but this formula is pretty straightforward:

High Soil Temps + Saturated Soil = Root Loss

Ideally, there is an equal amount of air and water in the soil pore spaces.  Any soil that is full of water--especially hot water--does not bode well for plant health.  As you can see below, from the sensors buried in the greens, during mid-July, we had soil temperatures as high as 96 degrees.

Water transfers heat much more effectively than air (which is why 65 degree air feels alright to us, but 65 degree water feels really cold).  When heavy rains hit this baking soil last month, root loss was significant.

Another factor is that Laurel Creek's greens are predominantly Poa Annua.  Due to its inherently short root system, this grass is already at a disadvantage when compared to Bentgrass in the summer.  The picture below shows the vast difference in roots between our Bentgrass greens nursery on the left, and a plug of Poa from a collar on the right.

Bentgrass versus Poa roots

To insure that there aren't other factors at play here, soil samples were taken from greens, tees and fairways, and examined by both Steve McDonald of Turfgrass Disease Solutions, and Rich Buckley of Rutgers Plant Diagnostic Laboratory.  They are in agreement that the primary cause of any turf decline is due to abiotic (non-living) stress.

Even just foot traffic from golfers can lead to thinning on weakened turf.

While Bentgrass tends to be more tolerant of summer heat than Poa, the tees and fairways are also showing signs of fatigue from the weather.

The left side of #15 fairway contends with a tremendous amount of runoff from the golf course and beyond.

At this point, it may seem somewhat ironic that while excess water has been a large contributor to the current situation, it is now necessary to water more often.  That is, with very little roots to draw moisture from the soil, allowing things to firm up will lead to turf loss.  Small amounts of water must be applied frequently to prevent the plants from wilting.

We have taken several steps to minimize turf damage.  In all of the fine turf areas, the application schedules for plant protectants have been tightened.  On the greens, we have made some other changes to further reduce plant stress, and protect the long-term health of the putting surfaces.  This includes backing off on double-mowing and rolling.

Additionally, we have installed less aggressive solid front rollers on the mowers.  While the mowers are set at the same height of cut, these rollers will have a higher effective height, leading to a smooth, but slower putting surface.

Hand mower with a smooth roller on the left, and grooved roller on the right.

We always try to plan for the worst and hope for the best.  However, it appears that the bar may have been raised on what the worst weather can be.  At times like this, there are many lessons to be learned, and changes to be made in the future.  Aerification is right around the corner, and Labor Day soon thereafter.  While that may not be a date that everyone looks forward to, it typically means better grass-growing weather, and improved conditions on the course--something we can all appreciate.