Greenhouse strawberry greenhouse production in Ontario, Canada has dramatically increased in recent years. This rise in strawberry production is primarily driven by consumer demand for high quality fruit year-round. To achieve true year-round production, supplemental lighting is needed to compensate for the low sunlight condition during the winter months. Photoperiod extension (up to 24 hour(h)) is a promising strategy which can be implemented in Canada as the utility companies incentivize the use of low cost, off-peak electricity use during the night. Our study aimed to look at the impact of various lighting treatments with photoperiods up to 24h on strawberry growth, production, and fruit quality. Three ever-bearing strawberry cultivars ‘Albion’, ‘Favori’, and ‘Bravura’ were grown in four adjacent double-poly greenhouse at the Harrow Research and Development Centre in Harrow, Ontario, Canada from fall of 2023 to spring 2024. The plants were subject to 4 lighting treatments: 16h of white light (16W), 16h of white light plus far-red (16WFR), 16h of white light followed by 8h of blue light (16W8B), and 16h of white light followed by 8h of blue and far-red light (16W8BFR). Plants under all light treatments were subject to the same DLI. In all strawberry cultivars, plants grown under 16W8BFR produced a similar fruit number and cumulative fruit weight as those grown under 16W and 16WFR. In addition, strawberry fruit produced from plants grown under both 16W8B and 16W8BFR had similar Brix or titratable acidity values when compared to fruit from 16W and 16WFR treatments. In depth physiological responses to extended photoperiods will also be discussed. The results show that in three ever-bearing strawberry cultivars, 24h lighting is a viable production strategy which can reduce the electrical cost associated with lighting while maintaining fruit yield and quality.
