Extension of the strawberry (Fragaria × ananassa Duch.) season in Estonia using ever-bearing cultivars and covers during the winter
The open-field strawberry season in Estonia is very short, lasting from the mid-June to mid-August. The aim of the research was to prolong the season by growing the ever-bearing strawberry cultivars Diamante, Cabrillo, Harmony and new line FF1604 in tunnels and using covers during winter, evaluating yields and winter hardiness. Strawberries were planted in May 2017 on table tops in peat substrate bags (8 plants per bag, 10 bags per cultivar). The yield was harvested from July 4 until September 26. At the end of November, the plastic was removed from the tunnels, and plants in the substrate bags were lifted to the ground and covered with double fleece row cover or double anti-frost net. Temperature loggers were placed into the substrate at depth of 3 cm. Row covers were removed at the beginning of April and freeze damage of 8 crowns per cultivar and row cover was assessed. The rest of the plants were lifted to table tops and grown until the end of August. In the first year, the highest yield was obtained from Harmony (502 g plant‑1), but the largest fruits from Diamante (average size 22.2 g). The average and minimum substrate temperature under fleece was 0.2 and -2.2°C and under anti-frost net 0.5 and -2.7°C, respectively. On average, plants had medium freeze damage (from 1.5 to 2.6 in 3-point score) without significant difference between row covers. Overwintered plants produced very low yield (from 139 to 240 g plant‑1). Conclusively, growing ever-bearing strawberries in tunnels enabled to prolong strawberry season in first year from usual 6-8 weeks to 13 weeks. However, overwintering of ever-bearers in substrate bags caused serious freeze damage to plants despite the row covers and therefore cannot be recommended in Nordic conditions.
Moor, U., Põldma, P., Starast, M., Mainla, L., Tõnutare, T. and Karp, K. (2020). Extension of the strawberry (Fragaria × ananassa Duch.) season in Estonia using ever-bearing cultivars and covers during the winter. Acta Hortic. 1268, 143-148
freeze damage, fleece, anti-frost net, yield, 'Harmony', 'Diamante', FF1604