Why do greenhouse growers need to control temperature, humidity, light, water, and pollination?

Greenhouse growers must meticulously regulate environmental factors because they are responsible for tasks typically managed by nature in open fields. By controlling these variables, growers ensure that each factor remains at an optimum level, as any deficiency can limit plant development and prevent maximum yields.12

• Temperature: Growers use heating systems and ventilation to maintain specific ranges—such as 40° F for lettuce or 70° F for tomatoes—to prevent crop injury and suit the needs of specific plants.1
• Humidity: High humidity increases the efficiency of water use by decreasing the evapotranspiration rate.3
• Light: Light provides the energy for photosynthesis. Growers use supplemental illumination to increase energy values or manipulate the photoperiod to control flowering times.42
• Water: Providing consistent soil moisture is essential, as unfavorable moisture conditions combined with temperature fluctuations can cause the loss of buds, flowers, and small fruits.21
• Pollination: Because natural pollination may be unreliable, growers must often facilitate the transfer of pollen to ensure proper fruit size, shape, and flavor.51

Ultimately, the interrelationship of these factors is critical; failing to optimize them can significantly reduce crop quality and yield.2