It is not just the nutrient solution that is an important source of nutrition for your plant, but also the carbon dioxide that is made available to the plant in the growing environment. In a typical plant, water accounts for the vast majority of its total weight, with the rest being made up of ‘dry matter’. The vast majority of the ‘dry matter’ is in the form of carbohydrate, which is sourced from the atmosphere in the form of carbon dioxide and then, converted by the plant.
Therefore, it is extremely important to maintain adequate air exchanges in the growing environment, so as not to starve your plants of the carbon dioxide that they vitally need.
In addition to this, air exchange also helps to control the levels of temperature and humidity within the growing environment. These factors are usually, but not exclusively, controlled by ventilation.