Effects of vent opening, wind speed, and crop height on microenvironment in three-span arched greenhouse under natural ventilation

•Under natural ventilation, the wind speed has the least impact on the microenvironment in the greenhouse.•Side vent opening and crop height significantly affect the microenvironment in the greenhouse, and they have the best matching relationship.•When only the inter valley vent is opened, the HREs are the smallest and close under various crop height and wind speed.•When the side vent openings are the same, the height of the horizontal layer of the lowest temperature increases with the increase of crop height.