While many golf course maintenance crews use portable or in-ground soil moisture sensors to accurately measure volumetric water content (VWC) in the rootzone, applying the “right” amount of water when hand watering greens is somewhat subjective. At Philadelphia Cricket Club, chief planning officer and director of grounds and facilities, Dan Meersman, created a hand-watering method that improves rootzone moisture consistency across all the putting greens and also provides guidelines to help train inexperienced hand waterers.
Meersman’s staff uses portable moisture meters to measure and record putting green VWC over all 45 holes and practice facilities at Philly Cricket. The management team then considers the forecast evapotranspiration (ET) for the day compared to the current rootzone VWC to determine the volume of water that should be applied by hand watering to achieve the desired VWC. For example, when VWC readings are less than 10% with ET predicted above 0.15 inch, staff will apply 0.03 inch of irrigation water. Of course, the necessary amount to apply on each green will vary from course to course and seasonally. This hand watering is done in the morning with the goal of meeting turfgrass water needs for the day.
Hand-watering staff refer to their golf course’s “watering card” which lists each putting green and the specific gallons of water to be applied based on the predetermined ET replacement volumes. Just before the hand waterer plugs in their quick coupler, an in-line flowmeter on the hose is zeroed and water is applied while monitoring the flowmeter for even dispersion, while still allowing extra water for any fresh plugs or drought-stressed areas. After a few hand-watering applications, the staff learns the necessary pace to evenly apply water but always refers to their flowmeter to ensure accuracy. This results in the desired amount of water being applied to the putting greens and lessens the subjectivity in hand watering while aiding in training.
Measuring putting green surface area, purchasing in-line flowmeters and obtaining reliable ET rates for your location is about all it takes to implement Meersman’s method. Even if you’re not looking to develop a watering card, thinking about the volume of water applied in the context of putting green surface area can be an insightful exercise. For the calculations, use this formula:
Volume of Water to Apply (gallons) = Putting Green Area (square inches) x Depth of Water to Apply (inches) x Conversion Factor (cubic inches to gallons).
For example, a 4,500-square-foot putting green is multiplied by 144 to give 648,000 square inches. Depth of water to apply is the other variable and is related to daily ET.
Common presets for the watering card are 0.03, 0.05, 0.07 and 0.10 inch. The conversion factor is 0.004329, which converts cubic inches to gallons. Using the equation for a 4,500-square-foot putting green that requires 0.05 inch of irrigation water to replace loss from predicted ET, we see that: 648,000 square inches x 0.05 inch x 0.004329 = 140 gallons of water. That is the amount of water that should register on the flowmeter when the hand waterer is done with that green.
I was fortunate to see this hand-watering method in action during the 2024 U.S. Amateur Four-Ball at Philly Cricket, which started with a notable rain event that was followed by an abundance of dry weather and very high ET days. The putting green firmness was excellent and highly consistent throughout the golf course, which was a direct result of precise hand watering. If you want to elevate your water management, consider implementing some of the ideas from the Meersman method and definitely measure VWC using a tool like the new USGA Moisture Meter. For further discussion on water management, reach out to your regional USGA agronomist.
Northeast Region Agronomists:
Darin Bevard, senior director, Championship Agronomy – dbevard@usga.org
Elliott L. Dowling, regional director, East Region – edowling@usga.org
Brian Gietka, agronomist – bgietka@usga.org
Information on the USGA’s Course Consulting Service
Contact the Green Section Staff