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Turf managers are continually seeking improved grasses, management practices, and products that enhance heat and drought tolerance and reduce supplemental irrigation needs. To this end, products like seaweed extract (SWE) have been extensively studied on short-cut (≤12 mm) golf turf and seedlings of various turfgrass species exposed to stress conditions. Few studies, however, have reported SWE effects on mature, higher cut (≥38 mm) cool-season turfgrass swards. A 3-year field study (2013–15) was conducted in Connecticut to determine the effect of various SWE treatments on the normalized difference vegetative index (NDVI) response of nonirrigated kentucky bluegrass (Poa pratensis L.) and tall fescue (Festuca arundinacea Schreb.) turf managed as a lawn and cut at 76.2 mm. Separate experiments for each species were set out as randomized complete block designs with three replicates. Throughout the growing season in each year, various liquid SWEs were applied at a concentration of 9.55 L·ha⁻¹ weekly or 19.1 L·ha⁻¹ biweekly. A nontreated control was included. The study lacked extreme heat stress conditions during the yearly growing seasons, but periodic moisture deficits below normal were present. Within each year, there were no significant SWE effects on the NDVI of either species. The results suggest that there is no improvement in the NDVI by applying SWEs to mature, higher cut cool-season turfgrass lawns under less than extreme heat-stress conditions, water-stress conditions, or both. Because this study was conducted only at one site without extreme stress, further research of SWE applications to established, higher cut cool-season turfgrass lawns should be conducted across different locations and soils to determine the effects of applying SWE to these stands under extreme heat-stress conditions, water-stress conditions, or both.

Glyphosate is routinely used to eradicate existing turf in golf course fairway renovations. However, current label recommendations suggest delaying cultivation of glyphosate treated areas for 7 days. A 2-year field study was conducted to assess how various seedbed preparation techniques (i.e., verticutting, core-cultivation, or verticutting + core-cultivation) influence glyphosate efficacy on creeping bentgrass fairway turf when completed at various intervals shortly after application [0–7 days before cultivation (DBC)]. Percent green cover declined from initial values of ≈90% to ≤0.2% at the end of the study after glyphosate application at all timings, regardless of cultivation during both years. All cultivated plots had 37.9% to 72.3%, or 5.9% to 62.1% less green cover compared with noncultivated plots when glyphosate was applied ≤3 days before cultivation in 2014 and 2015, respectively. Generally, the number of days until green cover reached 1% (GC₁) ranged from 6.6 to 11.1 in 2014 and 5.2 to 6.9 in 2015. Within glyphosate application timings, no differences in GC₁ were observed between cultivated and noncultivated treatments in 2014, except at 0 DBC. The GC₁ for verticutting was 5.1 days longer than noncultivated plots; however, all other cultivation treatments were equivalent to noncultivated plots when glyphosate was applied 0 DBC. All cultivation treatments reduced GC₁ 1.7 to 2.5 days compared with the no cultivation treatment, regardless of glyphosate application timing in 2015. Results from this study indicate that cultivation of creeping bentgrass fairway turf within 7 days of glyphosate application is not detrimental to long-term herbicide efficacy, and in some cases may actually enhance the rate of decline of glyphosate treated creeping bentgrass.