Ventilation:
In addition to air exchange, ventilation is a critical factor for the proper functioning of a cultivation space. Air movement enhances the O2/CO2 exchange through stomata (resulting in increased vitality) and promotes the expansion of the plant structure (leading to higher yields). This circulation of air is achieved using fans or air circulators, which should be directed evenly and gradually towards the plants for optimal results.

Humidity:
In addition to temperature control, the use of extractors, intake fans, and circulators allows for the regulation of humidity (or relative humidity). Expressed in percentage (%), the amount of water vapor in the air is measured with a hygrometer and controlled by a hygrostat (which can be paired with the extraction/ventilation or humidification systems). In most cases, a grow room housing plants in the vegetative phase (growth) requires the use of a humidifier (preferably with a built-in hygrostat) or an ultrasonic fogger to maintain the ideal range of 50 to 70% relative humidity. These measures ensure optimal gas exchange through the stomata. Conversely, during the flowering stage, a relative humidity of 45 to 50% is sufficient to avoid potential mold issues.

A thermo-hygrometer measures both temperature and humidity, displaying the minimum and maximum values of these parameters. This useful tool should be placed at the center of the grow space and at the canopy level of the plants to record accurate data.

CO2 Injection:
To enhance plant growth and maximize production, some demanding cultivators opt for CO2 injection. This technique involves releasing carbon dioxide gas into the sealed grow room (with the installation of check valves at air inlets and outlets) to achieve a concentration of 1500 ppm. This can be effectively accomplished through two methods: sublimating dry ice (placed in containers) or controlled release of CO2 cylinders (connected to a solenoid valve and a CO2 controller equipped with a sensor). To prevent carbon dioxide poisoning, it is highly recommended to install a CO2 detection alarm.

Temperature:
The ideal temperature range for cultivation falls between 20°C and 25°C, with 23°C being optimal. The extraction/intake and ventilation systems play a role in controlling the temperature within the grow room. Maintaining a stable temperature can be challenging in the summertime when ambient heat combines with the heat generated by the grow lights. Two solutions are common: using an air conditioner or scheduling the lighting phase to start during the night to avoid the daytime heat. It's important to ensure that temperature fluctuations do not exceed 10°C between day and night to prevent unnecessary stress on the plants. Connecting a thermostat to the extractor and intake fan can help automatically manage temperature variations within the grow room.

Odor Control:
Managing odors is another crucial factor to avoid disturbing neighbors. Several products available on the market are highly effective, up to 100%: activated carbon filters, ionizers (devices releasing negative ions to purify the air), or ozone generators (requiring the setup of a separate chamber to place the generator). The most commonly used and cost-effective option is the activated carbon filter, which is a large cylinder filled with activated carbon that traps odors. It is easy to install, placed inside the grow space at the top and connected to the extraction circuit's inlet since heat and odors rise. Additionally, placing an activated carbon filter outside at the intake circuit's entrance ensures the prevention of intrusions by pests, dust, or unpleasant odors from the surrounding environment.

The selection of ventilation equipments
The ventilation of your grow room involves two crucial factors: the removal of hot air (depleted in CO2) and the introduction of fresh, new air. Hot air is evacuated using an air extractor from the VK series, while fresh air can either be passively supplied through an open window or introduced using an intake fan from the TT series, which can also be used as an extractor. Knowing the room's size and the number of lamps to be used, you can calculate the required ventilation in cubic meters per hour (m³/h).