With summer storms being hit or miss, the decision to irrigate or not, can be a roll of the dice. Truth be told, there's likely an average of two or three times each year when we wait until nightfall to make the call on irrigation, and wakeup to find that what looked like a solid line of storms fell apart--or the opposite happens, and the "pop-up" storm has dumped a bunch of water after we gave the heads a couple of spins.
Beyond the impact on playing conditions, this can be a humbling experience when you are maintaining turf at 1/10" in the transition zone. Currently, the roots of the Poa in the greens is about the depth of a hockey puck, thus drying down the greens is not an option. So even if moisture is in the soil profile down deep, we have to manage to what is referred to as the "functional" root zone--that is, where the Poa roots are able to pull water from.
Many times what appears to be a solid line of rain splits while approaching Philadelphia from the west, leaving Laurel Creek in the "miss" zone as it rains to our north and south after crossing the Delaware River. A number of years ago there was an article which proposed three possible reasons this storm split may occur:
- The elevation change from the hills of eastern interior Pennsylvania, to the lower, flat elevations of the Delaware River and south Jersey.
- The Delaware River itself may impact the storms as they approach.
- The enormous heat of the city acts to break up storms.
As you can see below, a recent storm begins to split to the north and south as it passes the city, and crosses the Delaware River.
After this line of heavy showers passes Philadelphia and the river, the golf course is left in the "two drops" zone.
Regardless of the reason or reasons this occurs, relying on irrigation is always less uniform than rainfall, and turf rarely responds to irrigation water as it does to nature's water from above.
Obviously having to irrigate this time of year is to be expected. However, this year has been unusual both in terms of heat as well as the need for supplemental water. As of July 28, much of the region is way behind in rainfall over the last six week period:
Sooner or later we'll be complaining about how cold and wet it is, but for the moment we're doing whatever it takes to make it through this nasty stretch of weather.