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Greenhouse Strawberry Production: Report of Cultivar Performance 2022-2023

By: Joy Johnson, Austin Wrenn, Mark Hoffmann

The predominant method for strawberry production in North Carolina and throughout the United States is annual hill plasticulture. However, growers continuously face challenges such as escalating labor and production costs, heavy pest and disease pressure, and recurrent yield losses due to extreme weather events and climate change. Transitioning to a soilless greenhouse production system (e.g. table-tops) could be an avenue to alleviate some of these challenges. However, greenhouse strawberry production in North Carolina faces a host of other challenges, one of which is the lack of knowledge on cultivar performance. To help growers better understand cultivar behavior in greenhouse conditions in NC, this study aimed to evaluate the performance of seven commonly grown cultivars (‘Albion’, ‘Brilliance’, ‘Camino Real’, ‘Fronteras’, ‘Monterey’, ‘Sensation’, ‘Sweet Charlie’) in a commercial strawberry greenhouse setting in Eastern North Carolina. The greenhouse was a multi-bay, mid tech, double poly plastic covered facility. The trial, which was planted in September 2022 and concluded in May 2023, was conducted on-farm using a randomized complete block design with four replicates per treatment. Although overall yield comparisons did not reveal any significant differences among cultivars for the season as a whole, there were notable differences during specific months of the harvest period which lasted from December through May. The two everbearing varieties in the trial, Albion and Monterey, were the earliest producers of fruit, while the standard short day varieties, Camino Real and Fronteras, had almost no early yields, but demonstrated substantial peak season production in April. Postharvest quality evaluation included pH, TA (total acidity) and Brix (soluble solids content). Although pH and TA were fairly similar over all cultivars, brix was more variable, with Sweet Charlie having the highest average brix and Brilliance having the lowest average brix.

Soil-Less Substrates for Greenhouse Strawberry Production in the Southeastern US

By: Austin Wrenn, Brian Jackson, Mark Hoffmann

Soil-less growing practices have opened up new possibilities for many specialty crops, including strawberries. US strawberry growers are facing a number of challenges that threaten the future of the industry. These include increasing labor and production costs, increased competition from imports, short production seasons, new emerging pests and diseases, extreme weather patterns and new government regulations. Soil-less production of greenhouse-grown strawberries has the potential to address some of those issues. While soil-less greenhouse strawberry production has been common for many years in a number of European and Asian countries, it has yet to become commonplace in the US. Reasons are high upfront cost as well as a general lack of technical knowledge, resulting in grower reluctance to make a transition into greenhouse strawberry production. One horticultural key for a successful soil-less strawberry production system is the choice of optimal substrate options. Therefore, the presented study evaluated the impact of six substrate blends on the growth and yield of strawberry (Fragaria x ananassa cv. Albion) in a commercial greenhouse in Eastern North Carolina. Following substrate blends were used: (1) 100% Coco Fiber; (2) 50% Canadian Peat / 50% Perlite; (3) 50% Canadian Peat / 50% Coco coir; (4) 50% Canadian Peat / 50% Wood Fiber; (5) 50% Canadian Peat / 50% Bark; (6) European Peat. Tray plants (250 cc) were grown in a modified tabletop system inside a poly-covered greenhouse with basic climate control infrastructure. The study was conducted in a randomized complete block design during the growing season 2020-2021 and repeated in 2021-2022. Our results show that strawberries grown in 50% Canadian Peat / 50 % Wood Fiber yielded similar high to 100% Coco Fiber and 100% European Peat, both grower standards. Based on the research, strawberry greenhouse production could use more cost effective, local available woodfiber and Canadian peat substrates instead of coconut coir or European peat that are sourced and shipped overseas. This option can be a more cost effective option for growers in the Southeast, considering making a shift to greenhouse strawberry production.