In Türkiye, greenhouses without regular heating typically begin cultivation in March due to ecological reasons. However, low temperatures that occasionally occur during these months negatively impact cultivation. This study aimed to monitor inside climate parameters in high-tunnel greenhouses and evaluate measures to be taken. To this end, inside and outside temperatures, relative humidity, dew point temperature, canopy surface temperature, water condensation on the canopy's inner surface, light intensity, solar radiation, and photosynthetic active radiation were measured in March in the high-tunnel greenhouse and evaluated for cultivation. Data logger measurements revealed outside temperature and relative humidity values ranging from -5.7 to 11.0 °C and 53.4% to 91% throughout the trial. Inside temperature and relative humidity values ranged from -4.7 to 27.7 °C and 52.4% to 85.9%. Considering the low temperatures and high relative humidity values encountered during these periods, heating and ventilation of greenhouses becomes essential. Otherwise, the cover surface temperatures will drop below the dew point, causing condensation. Depending on the difference between inside and outside temperatures, water condensing on the inner surface of the cover can reach up to 90.1 g/m²/h. Furthermore, this condensed water on the cover surface has been determined to promote fungal diseases and reflect 67% ...
