Continuous Lighting to Reduce Electricity Cost and Greenhouse Gas Emissions in Greenhouse Cucumber Production

Supplemental lighting is essential for winter production of fresh fruits and vegetables in northern regions, but it increases electricity use. While technologies such as LED fixtures help reduce energy consumption, costs, and greenhouse gas (GHG) emissions, further improvements are needed for sustainable production. Continuous lighting (CL) distributes light at lower intensities over a 24h period to achieve the same daily light integral as shorter, higher-intensity photoperiods. This approach enables nighttime electricity use, which is typically cheaper and generated from lower-emission sources such as hydroelectric and nuclear power. This study evaluated CL in cucumber production. For mini cucumber cv. ‘Beesan’, CL increased yield per CO₂e emitted by up to 38.9% and reduced lighting electricity costs by up to 26.0% compared to a 16-hour photoperiod. For long English cucumber cv. ‘Sequence’, yield per CO₂e improved by up to 37.9%, with cost reductions up to 25.8%. Results also showed cultivar-specific responses, highlighting the importance of genotype selection when using CL. Overall, continuous lighting is a viable strategy to lower electricity costs and GHG emissions while maintaining yield and profitability in greenhouse cucumber production.