Yes, you definitely need circulation fans in most greenhouses, especially those with heating, automated ventilation, and/or light deprivation! In addition to cooling and exhaust fans, your plants will benefit greatly from circulating air. Circulation fans, also known as horizontal airflow fans (HAF), provide continuous air movement which helps maintain uniform temperatures, humidity, CO2, and increases the structural integrity of the plants much like the wind strengthens plants in nature.

On a plant level, optimum air circulation increases transpiration (the process of the leaf absorbing and expelling moisture). Too much airflow can result in “windburn” aka “clawed leaves.” However, circulatory airflow is especially important in light deprivation greenhouses. It can also be beneficial in greenhouse heating to mix air and maintain a uniform temperature throughout the greenhouse.