Watering practices have nearly as much effect on playability of greens as mowing practices. Wet greens provide poor playing conditions and lead to infestations of weeds and algae. Ball marks and foot printing are also problems on wet greens. On the other hand, dry greens are usually very hard and don’t hold a well-played golf shot.
Watering practices must be based on soil properties, grass species, environmental conditions and other maintenance practices. Watering schedules are critical on greens with poor drainage or on greens with excessively high infiltration rates. Properly constructed greens allow a much wider margin for error in watering schedules.
Greens with poor drainage must be watered slowly, or at frequent intervals, to wet the soil 4 to 6 inches deep. On poorly drained greens, if water is applied at rates above 0.5 inch per hour, water runs off the green faster than it moves into the soil. Thus, the collar and apron get wet before the putting surface is adequately watered. Automatic systems should be cycled so that water is applied intermittently to such greens. Intermittent watering allows water to penetrate several inches into the soil before excessive runoff occurs. Then, with the exception of spot watering, greens should hold up several days without watering.
Sand greens with very high infiltration rates require light and frequent applications of water. Again, the collar and apron of these greens are often wet while the putting surface appears dry. Careful design of the irrigation system may be required to maintain the putting surface without keeping the surrounding area wet.
Environmental conditions have more influence on watering than any other factor. Water use rates may vary from 0.05 to 0.3 inches of water per day depending on temperature, wind, humidity and sunlight. In drier climates during summer months water use rates will approach 0.3 inches of water per day. Under these conditions, frequent watering is almost a necessity. During cooler months, water use rates are less than 0.1 inch of water per day and weekly watering may be adequate. Watering schedules must be adjusted according to fluctuations in water use rates. For lack of a more accurate measure of water use rate, daily evaporation readings available from meteorological stations may be used to estimate water use rates. In most southern climates daily water use rates are about three-quarters of the daily evaporation rate reported by the weather bureau.
Management practices such as dethatching and aeration also influence watering practices. Thatch restricts water penetration and leads to shallow rooted turf. Thus, light and frequent applications of water are required on thatchy greens. Vertical mowing, aeration and topdressing aids thatch removal and decomposition and improves water penetration. Spiking and coring also help to alleviate crusts and surface compaction. Thus, these cultivation practices improve moisture conditions on greens and allow for longer intervals between irrigations.