2018 ASHS Annual Conference

Increasing demand for locally grown produce with high flavor quality has led to a significant increase in controlled environment strawberry production in recent years. Additionally, challenges in traditional open field production, including loss of methyl bromide and labor shortages, could lead to soilless systems dominating the future market. Soilless substrate mixes need to be optimized for plant productivity, plant health, and ultimately grower profit. This study investigates effects of four different substrate mixtures on ‘Albion’ strawberry plant vigor, fruit yield, and fruit quality. The four substrates tested were 1) a commercial mix developed for strawberry production, consisting of peat moss, perlite, chunk coco coir; and beneficial microbes (arbuscular mycorrhizal fungi (AMF) and biofungicide bacteria); 2) another commercial strawberry substrate mix composed of peat moss, tree bark fiber, coco coir fiber, and the same microbial supplement; 3) our standard lab substrate for strawberry containing perlite, coco coir, and peat moss; 4) the same lab substrate with supplemental AMF. Forty-eight ‘Albion’ plants were grown in each of the four substrates from September 2017 to April 2018 in a 103 m² glass greenhouse at The Ohio State University (Columbus, OH). Vegetative growth, fruit yield, and fruit quality (Brix and titratable acidity) were evaluated throughout the production period. At the transplant stage (September 12 – November 20, 2017), strawberry plants grown in Substrate 2 had the highest root-to-shoot dry mass ratio (1.10±0.36) followed by Substrate 1 (0.67±0.14), Substrate 4 (0.62±0.080), and Substrate 3 (0.54±0.070) indicating that use of commercial strawberry substrate mixtures or the addition of beneficial microbes to our standard substrate mix led to greater root development in early growth stages. Early fruit yield per plant (recorded from December 1, 2017 to February 7^th, 2018) was significantly greater in Substrate 4 (187.3±4.6 g) and Substrate 2 (183.3±6.2 g) than in Substrate 3 (143.9±11.6 g) (Tukey HSD, P=0.05). However, no significant difference was observed between Substrate 1 (164.6±10.1 g) and any of the other three substrates. Furthermore, the average fruit size during the same early production season was the greatest in Substrate 2 (20.9±0.27 g) and there were no significant differences among the other three substrates (ranging between 17.2±0.84 and 18.6±0.27 g) (Tukey HSD, P=0.05). These results show increased productivity in plants grown when beneficial microbes were added in specific substrate mixes, suggesting the importance of chemical, physical and biological properties of substrate used in soilless strawberry production.