Early establishment increases yield and fiber quality of industrial hemp ( <i>Cannabis sativa</i> L.) produced in the Mid‐Atlantic

Abstract Planting dates (PDs) are well established for a wide range of agronomic crops to maximize yield and quality, but this guidance is lacking for industrial hemp ( Cannabis sativa L.) produced for fiber, especially in the Mid‐Atlantic region. With fiber hemp cultivation commencing with the passing of the 2014 and 2018 US Farm Bills, it is imperative to understand how this crop can fit into established crop rotations. Therefore, the objective of this research was to determine optimum planting and harvest dates for fiber hemp in the Mid‐Atlantic to optimize plant characteristics. We hypothesized that earlier planting and harvest would increase fiber hemp yield and quality. The 2‐year study was performed in two locations in Maryland (three total site‐years) and utilized a split plot, randomized complete block design with PD as main plots and either variety or harvest date as split plots. The results indicated that to maximize fiber hemp yield and associated desirable plant traits, hemp must maximize light interception throughout the entire summer growing season; therefore, shortened‐season fiber hemp is not likely to maximize productivity. These results are promising for the incorporation of fiber hemp into current crop rotations in Maryland and the greater Mid‐Atlantic region. Data supported that lignin was the only fiber quality parameter affected by PD, with earlier plantings having increased content. This information allows farmers to make informed decisions about the impacts of PD and the desired end product. The flexibility around optimal PD of fiber hemp allows farmers to prioritize planting of summer cash crops, such as corn and soybean, ahead of fiber hemp while minimizing concerns of negatively impacting fiber hemp yield.