The effects of propagation temperature, CO2 concentration and early post-harvest night temperature on the fruit yield of January-sown cucumbers

SummaryGrowth and fruiting responses of four January-sown cucumber cultivars to two propagation temperatures (day 21°C, night 19°C and day 24°C, night 17°C), three levels of CO2 enrichment (400, 1000 and 1600 vpm) and three stages of post-planting night temperature reduction (0, 3 and 6 weeks after first harvest) were examined in a glasshouse experiment. Early (4-week) fruit yield and monetary returns were significantly increased when the higher day temperature treatment was combined with the 1600 vpm CO2. The early advantage was soon lost and after 20 weeks harvesting there were no differences between the propagation temperature treatments. After two weeks of CO2 treatment total dry weight of aerial parts, leaf area and stem length were increased by 88, 73 and 69% respectively when the CO2 level was raised from 400 to 1000 vpm. A further rise from 1000 to 1600 vpm produced no further increases indicating that 1000 vpm is probably near the optimum concentration for growth at the temperatures applied. In t...