What environmental factors do you need to keep in mind if you want to grow healthy, large flowers or vegetables in a greenhouse or indoors?

Plants get everything they need when grow outdoors, so they grow optimally and produce plenty of yield. Of course, outdoor crops can be hampered by bad weather, insects or other negative factors. Since natural conditions are not ideal in a closed space, it is important to artificially create the environment essential for the growth of the plant.

In this article, we look at four key environmental factors for optimal plant development:

  • air exchange, air movement
  • carbon dioxide level
  • temperature
  • humidity

The plant’s gas exchange takes place through so-called stomas, which are tiny air holes at the bottom of the leaf. The stoma is the site of cellular respiration, photosynthetic gas exchange and evaporation, which regulates the water balance of the plant. Gas exchange is a physical process in which the plant absorbs the gas it needs (carbon dioxide when exposed) and releases excess gas (oxygen when exposed), while in the dark the opposite occurs.

The operation of stomas is also influenced by the ambient temperature and humidity, so it is important to be able to create and maintain the ideal environment for the plant’s needs.

Air exchange in the growing area

You can use one or more duct fans to provide the air change needed for the plants. The ideal air change is 1 to 3 per minute based on grow tent manufacturers recommendation. For larger rooms, it is recommended to use an intake fan and an exhaust duct fan at the same time, while a smaller room or a grow tent will require a single exhaust fan.

The air movement capacity of the duct fan must be adapted to the size of the room to ensure the required air exchange. The fan location should be placed on the ceiling of the room (warm air will be lift up and replaced by fresh cooler air), thus ensuring an even air exchange.

Here’s a brief example of how to calculate air exchange for a 120 x 120 x 200 cm grow room:

Recommended for 2x air changes per minute: 1.2 x 1.2 x 2 meters = 2.88 x 2  = 5.76 m3 / min

Recommended hourly ventilation rate: 5.76 * 60 = 345 m3 / h

If the air travels several meters in the ducting and you want to use a charcoal filter or silencer, you should choose a fan with 5-10% more air exchange.

duct fan, can-fan, can fan ventAn entry-level duct fan has a single-speed motor, IPX4 protection, 40-50 DB operating noise and overheating protection.

For convenient operation, it is recommended to optimize the duct fan with a sound-insulated ventilation duct, a silencer, and a dimmer.

In this category we recommend the Vents VK, Vents VK UN and Can-Fan RK series duct fans.


duct fan, speed controllable duct fan, Vents TT UN, inline fan, extraction fanMid-range duct fans have dual-speed motors, IPX 4 protection, auxiliary and centrifugal fans so they provide high performance airflow with lower noise levels of 30-40 DB.

Another benefit of the Vents TT UN series is the built-in speed controller and thermostat, which automatically controls the temperature in the growing room through the fan speed control.

We recommend the Vents TT UN and Can-Fan Max-Fan Pro fans in this category.

silent duct fan, low noise vent, sound isolated fan,


The high end duct fans are equipped with two or three speed motors, IPX 4 protection, axial and centrifugal fans and overheating protection.

Another benefit is the extra quiet operation of 20-30 DB, which is achieved with factory-designed silencing.

Vents TT Silent-M and Can-Fan Q-max are the best choices in this category.

The performance of the duct fans can be further optimized with the following accessories:

muffler, silencer, duct fan muffler, duct fan noise reducerinsulated ducting, isolated tube, insulated vent pipedimmer, speed controller, performance regulator






Moving the fresh air as much needed as it can get to the leaves where the plant can utilize it.

Air movement can be done with ventilators of different power and design:

clip on fan, ram fan, small fanfloor fan, steel fan, room fan, stand fan, room fan, ventillation fan, ventilator

Maintaining carbon dioxide level in the grow area

Carbon dioxide plays a very important role in plant life processes. The atmosphere contains 300-415 ppm CO2 particles which is enough for outdoor plants. Indoor plant growers can be challenged to maintain optimal levels, as plants quickly use up the amount of CO2 available. Regular ventilation (2-3 air changes per minute) or extra CO2 can help maintain the optimal carbon dioxide level.

When the carbon dioxide level reaches 1000-1500 ppm, the plants produce 30-50% more yield and the harvesting time is reduced by 7-10 days.

The following table gives recommendations for carbon dioxide supplementation recommended for crop production.

  • 100 and 300 μmol / m2 / s for germination, seedlings, clones (under optimal conditions: additional CO2, ~ 400 ppm)
  • 300 and 600 μmol / m2 / s during development (optimal results: additional CO2, ~ 400-800 ppm)
  • 600 and 1000 μmol / m2 / s for optimum results during the flowering / reproduction phase (for amazing results: additional CO2, ~ 800-1400 ppm)
  • 1000 and 1500 μmol / m2 / s for outstanding results during the flowering / reproduction phase with additional CO2, ~ 1400 ppm.

There are 3 types of carbon dispensers available at the webshop

carbon dioxide dispenser, carbon dioxide supplement, carbon dioxide enhancer






Temperature control in the grow room

The temperature in the grow room should be adapted to the needs of the plant. It is important to know the temperature at which the chosen plant feels well. For example, lettuce develops best at 20 degrees Celsius, while tomatoes / peppers feel better at 26 degrees Celsius. Therefore, it is worth being careful about growing different plants in one place.

The automatic control of the temperature can be ensured by the Vents TT UN adjustable duct fan. Because temperatures can easily rise above 30 degrees Celsius during the summer months, which is not ideal, we recommend the using of an air conditioner. Temperature regulation should take into account that conventional HID bulbs increase the room temperature by 5-8 degrees Celsius, while LED lamps produce negligible heat.

We recommend the following tools to control the temperature:

digital temperature and humidity meter, temperature sensor, humidity sensor, Wireless Thermostat, temperature controller, enviroment controller, heater regulator, cooler regulator, temperature regulator, Lighthouse Wireless thermostatecoheat, lighthouse, greenhouse heater, heater tube, grow room heating greenhouse heater, greenhouse heating, Lighthouse heater

Humidity control in the grow room

Humidity control is very important in a closed grow space. A poorly designed room will provide an ideal environment for various fungal, mold and other infections in case of high humidity and poor ventilation.

Optimal development of seedlings and young seedlings requires a high humidity of 70-80%, which is easily achieved in a propagator (mini greenhouse).

Larger plants in the growth phase already feel comfortable in a slightly lower humid environment with a relative humidity of 50-60%. This can be achieved by regular spraying with water or using a humidifier.

Humidity control has the most importance for plants in the flowering / fruiting phase. Humidity levels of 30-40% should be maintained throughout this life cycle, which can be controlled by a dehumidifier.

We recommend the following accessories to control humidity:

temperature controller, thermostat, cooling controller, heater controller, Conrwall thermostathumidifer, fogger, ultrasonic humidifierdehumidfier

Automate your grow room with the GrowDirector environment controller

The GrowDirector is an automatic environment controller that transforms crop production into a fully interactive and automated process.

enviroment controller, climate controller, environment regulator, environment controller, GrowdirectorYou can be a successful plant grower without any prior experience, as you can control all environmental factors with GrowDirector or through a mobile application.

The power of this versatile environment controller is 2300 watts, sufficient to control a 5 x 5 meter area in a fully automated manner. No matter if you need more power, you can easily chain the devices together to multiply the total power.

GrowDirector can cover all environmental aspects of agricultural and hobby farming, such as lighting, airflow, fire and flood detection, irrigation, nutrient dosing, pH correction, tank management, IP camera monitoring, Co2, etc. send various notifications and remote control.

GrowDirector can be adapted to any environment, regardless of size, type, growing medium or growing system.

GrowDirector is available exclusively from PlayGrowned, you can find more product details at the link below:

Growdirector automatic enviroment controller

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