ASHS 2024 Conference

Strawberries are typically grown in high tunnels in the Intermountain West region to protect the flowers and buds from early and late-season frosts and extend the growing season. Organic farmers rely on N mineralization from organic sources to supply plant-available N which can be inadequate for plant needs, especially when temperatures are low. To support cultivar selection for organic strawberry production in high tunnels, greenhouse cultivar trials were conducted to determine if some strawberries grow better on compost than others. Plants were grown for six weeks in a mixture of turface and peat moss with and without compost. A complete liquid fertilizer with and without added N was supplied daily. Leaf, crown, and root dry weights, tissue, and compost N at the beginning and end of each trial were measured and leachate was collected daily and analyzed for nitrate and ammonium. Plant chlorophyll was determined at the end of the experiment. Plants that received liquid N fertilizer grew more, absorbed more N, and had a higher chlorophyll reading compared to plants that received the compost and N-free fertilizer treatment. Ammonium was leached out of the compost-treated pots in the first two weeks while little nitrate was lost. Some cultivars performed better than others on the compost treatment. This suggests that some strawberry cultivars are better able to grow on organic nitrogen sources than others but, additional N fertilization may be needed.