2019 ASHS Annual Conference

Florida’s subtropical climate allows two growing seasons (spring and fall) of hops (Humulus lupulus) per year. Supplemental lighting also plays an important role in creating two growing seasons by regulating the timing of flowering. Optimal crop management must be developed to maximize the yield potential of hops. In this study, we aimed to determine the optimal in-row plant spacing and nitrogen application rate for newly established hops in central west Florida. Tissue culture seedlings of 'Cascade' hops were established in a 5.8-m high trellis in February 2018. Harvests were performed in June in the spring season and December in the fall season. Treatments consisted of three levels of in-row plant spacing (76, 91, and 107 cm) and four nitrogen application rates (32, 56, 82, and 107 kg/ha in the spring season and 77, 148, 219, and 278 kg/ha in the fall season) in a factorial combination. The hop yield showed a linear increasing trend with N rate in both seasons. The maximum hop yield (dry weight) during the spring and fall seasons was 237 kg/ha and 190 Kg/ha respectively, at the widest plant spacing and the highest N rate. Plant growth also showed an increasing trend with N rate and it was positive and highly correlated with yield (r=0.85, p<0.001). The hop plants grew up better during the spring season compared to fall with more branches and biomass. The plant height, the fast growth of the bines, and the number of nodes with branching showed a positive nitrogen application response only during the spring season, but it does not for the fall season. Moreover, hop cones in spring had better quality compared to the ones in fall in terms of total oil and alpha acid contents. This seasonal effect was much greater than the effect of N rates, which was observed as a linear increasing trend for total oil content in spring and alpha acid content in fall. The lower performance during the fall season may be due to the hit heat stress that plants experienced during the summer combined with shorter day length during the rapid bine growth stage. This experiment shows that 427 kg/ha during the first year of crop establishment could be produced in Florida’s subtropical climates.