Reducing Lawn Mowing Frequency with PGRs.

Regular mowing is a necessary cultural practice unique to turfgrass. Unlike in other crops, above-ground yield is not coveted. It follows that we would investigate ways to reduce the frequency with which a lawn must be mowed, especially during the spring and fall growth flushes in temperate regions. The following research was initiated to better understand whether or not plant growth regulator (PGR) applications, once in the spring and once in the fall, could provide enough growth regulation to significantly reduce mowing frequency in home lawns. Two trials in which PGRs and combinations of PGRs were applied to a typical stand of mixed cool-season turf species, revealed that a significant reduction in mowing frequency could not be achieved. A third trial was initiated in 2017 on tall fescue on which trinexapac-ethyl (TE), TE + Proxy, prohexadione calcium (PC), PC + ethephon, and paclobutrazol were applied. TE + ethephon and PC + ethephon significantly increased the average mowing intervals to 18.6 and 16.1 days, respectively, compared to the untreated plots which were mowed, on average, every 8.2 days for 57 days after application. Turf heights were measured 3 days a week and plots were mowed to a height of 8 cm when they reached a height of 10.5 cm. No other treatment significantly differed from the control in mowing frequency. Both PGR combinations reduced turf quality although both remained at or above acceptable levels. This research has prompted further investigation of PGR combinations applied to reduce mowing frequencies on different cool-season species and during different seasons.