Maintaining a stable and homogeneous greenhouse microclimate is essential to maximizing the yield and quality of protected crops. However, achieving climate control in greenhouses involves much more than opening and closing windows: it requires carefully designed greenhouse ventilation systems, efficient greenhouse air recirculation, and greenhouse humidity control that prevents peaks and dead zones. Below, we explore the technical keys to achieving an optimal, efficient, and controllable environment, even with the thermal screens completely closed.
The challenges of air conditioning in protected crops
Every day, growers grapple with the complex task of maintaining a uniform temperature in their protected crops, preventing temperatures from exceeding 35°C in some areas while dropping below 18°C in others. These temperature variations not only affect plant development but also require frequent heating or cooling systems, skyrocketing energy costs.
At the same time, vapor management is another critical challenge: condensation on ceilings and foliage creates a breeding ground for fungi and bacteria that can ruin crops. Furthermore, light pollution regulations impose restrictions on opening thermal screens at night, further limiting options for ventilation and air renewal.
To address these challenges, state-of-the-art agricultural ventilation systems combine air delivery technologies from the top of the greenhouse with fans that recirculate the airflow at the crop level. In this way, temperature and humidity gradients are broken, generating an active, homogeneous, and healthy microclimate that maximizes performance and energy efficiency.
Forced ventilation: supply and extraction
Vertical fans for greenhouses
Vertical fans in greenhouses are installed at mid-height to draw air from an upper chamber or directly from the outside and redistribute it evenly from the canopy to the ground. By driving a constant flow, these devices break up the pockets of stagnant air that often form in higher areas, ensuring much more efficient air distribution in the greenhouse. Thanks to this continuous movement, thermal stratification is eliminated: the warm air that accumulates at the top descends and mixes with the cooler air at the base, significantly reducing temperature differences between the upper and lower parts of the crop. Furthermore, by circulating air over leaves and surfaces, these fans help dry residual moisture, achieving a drastic reduction in condensation in greenhouses and, thus, minimizing the risk of fungal diseases.
Air jets and upper diffusers
To further optimize air recirculation in greenhouses, vertical fans can be combined with air jets and top diffusers installed under the canopy or directly above the thermal screens. These devices introduce fresh air from the highest part of the structure and push it downward, creating a homogeneous mixing pattern that strengthens the greenhouse microclimate. This integrated system allows the screens to remain completely closed, as air renewal occurs internally, without the need for gapping. This way, nighttime light reduction regulations are met without sacrificing humidity control in greenhouses and temperature control in protected crops, achieving a stable and productive environment throughout all phases of the crop.
Air recirculation and humidity control
Proper humidity control in greenhouses achieves an optimal balance by combining constant air recirculation with localized extraction of saturated air. This approach eliminates excess vapor from structures and foliage, preventing condensation that favors the spread of fungal diseases. Maintaining relative humidity at appropriate levels not only improves plant health but also ensures a homogeneous agricultural climate, essential for uniform growth trajectories and consistent yields at all points of the crop.
To achieve this level of precision, humidity and temperature sensors are installed in strategic locations within the greenhouse, all connected to a centralized management system. When the sensors detect variations outside the desired range, the software automatically activates fans, diffusers, and extraction units, adjusting the airflow with the necessary precision. This optimizes energy consumption and ensures a stable microclimate without constant manual intervention, freeing the grower to focus on other key farm tasks.
Integrated systems for an active climate
The combination of greenhouse ventilation and air recirculation reaches its full potential when top-mounted jets and vertical fans are integrated into a single system. From the upper area, the jets introduce fresh air that mixes with the interior environment, breaking humidity and temperature gradients and preventing condensation from forming at critical points. In turn, the vertical fans redistribute this air throughout the entire crop, generating a smooth, constant flow that ensures a uniform atmosphere in every corner of the greenhouse.
Thanks to the automatic control of these devices—managed by a climate controller that regulates pressures, flow rates, and speeds—air exchange is optimized without the need for continuous manual intervention. This comprehensive approach not only maintains a stable greenhouse microclimate but also reduces the demand for additional heating or cooling systems, contributing significantly to energy savings in greenhouses. This allows growers to maximize the efficiency and profitability of their facilities.
Direct benefits in production
When a greenhouse has advanced temperature control for protected crops and air distribution in the greenhouse, the crops present:
- Increased biomass and fruit size.
- Reduced heat stress, reflected in less flower and fruit drop.
- Improved harvest uniformity, facilitating logistics planning.
- Reduced phytosanitary treatments thanks to lower residual moisture.
In practical terms, numerous farms have reported increased yields after implementing these integrated ventilation and recirculation systems.
Implementation and technical advice
For greenhouse ventilation and air recirculation to be effective, it is essential to:
- Preliminary diagnosis: analysis of the thermal and humidity profile within the structure.
- Custom design: optimal placement of jets and fans based on the greenhouse geometry.
- Sensor integration: control points at different heights and areas.
- Staff training: understanding the operation and maintenance logic.
- Ongoing support: adjustments during the first cycles to calibrate parameters.
A team of agricultural ventilation system specialists can support the entire process, from initial design to commissioning and post-installation monitoring, ensuring maximum performance.
Towards a truly homogeneous climate in greenhouses
Climate control in greenhouses has evolved from mere openings and heating to sophisticated active ventilation, recirculation, and intelligent humidity management systems. Investing in these technologies not only improves crop quality and quantity, but also optimizes greenhouse energy savings and facilitates regulatory compliance.
For professional agricultural producers, adopting integrated ventilation and air recirculation solutions is the best investment to achieve a stable greenhouse microclimate, reduce operating costs, and increase the profitability of their farms. With proper design and specialized technical advice, any greenhouse under plastic can be transformed into a highly productive, active environment.
