Greenhouse dehumidification is one of the most critical parameters of climate management in a protected environment. Too often, the focus is solely on heating, but it is relative humidity that dictates plants' ability to transpire, absorb nutrients, and resist pathogenic attacks. A greenhouse saturated with humidity is an ideal playground for fungi and bacteria, while air that is too dry can halt growth altogether. At Climatik, we provide professionals in the plant industry with cutting-edge technologies to maintain a perfect humidity balance, thus ensuring healthy and vigorous production all year round.

Why is humidity the grower's invisible enemy?

Under a covered or glass structure, humidity comes from two major sources: plant evapotranspiration and evaporation from the soil or substrate. During the night, or on cold and rainy days, this humidity accumulates.

Risks of poorly controlled humidity

Without rigorous greenhouse dehumidification, the consequences for crops are disastrous:

• Fungal diseases: Botrytis (gray mold), powdery mildew, and downy mildew develop as soon as relative humidity exceeds 85% for an extended period.

• Guttation and burns: When the air is saturated, the plant can no longer transpire. It expels water through its pores in the form of droplets, which can cause necrosis or promote the entry of diseases at the collar.

• Poor nutrient absorption: Transpiration drives sap flow. No evaporation = no sap flow = deficiencies in calcium and other essential minerals.

1. Traditional methods vs. active dehumidification

Historically, to reduce humidity, growers used the "heat and ventilate" technique: they open vents to exhaust humid air and simultaneously heat to maintain temperature.

Limitations of natural ventilation

This method is extremely energy-intensive. You are literally throwing your heat out the window! Furthermore, if the outside air itself is humid (rain, fog), this technique becomes ineffective.

This is where mechanical (active) greenhouse dehumidification comes in as a revolutionary solution, allowing air to be treated in a closed circuit without heat loss.

2. Climatik's greenhouse dehumidification solutions

Depending on the size of your operation and the type of crop (flowers, vegetables, medical cannabis, microgreens), several technologies can be deployed.

Condensation dehumidifiers (Refrigerant)

These are the most commonly used devices. They draw in humid air, recover water in liquid form (condensate), and discharge dry, slightly warmed air.

• Energy benefit: For every liter of water condensed, the device releases thermal energy (latent heat) that helps heat the greenhouse.

• Usage: Ideal for conventional production greenhouses with temperatures above 12-15°C.

Adsorption dehumidifiers

For crops requiring very low humidity levels or operating at low temperatures (e.g., bulb storage or cold greenhouses), these devices use a desiccant wheel that traps water molecules.

• Usage: Specific nurseries, research and development areas.

Technical guide: Calculating water extraction needs

To successfully implement greenhouse dehumidification, you cannot rely on mere estimation. At Climatik, we calculate the evapotranspiration rate of your plants based on:

1. Total leaf area (LAI - Leaf Area Index).

2. Light intensity (global radiation).

3. Growth stage (a plant in full bloom transpires much more than a young shoot).

The simplified formula for estimating water to be extracted is:

E = S x Tevap

Where:

• E is the amount of water to be extracted in Liters/hour.

• S is the cultivation area in m².

• Tevap is the average transpiration rate (often between 0.2 and 0.8 L/m²/h depending on the species).

Climatik Example: For a 500 m² greenhouse with dense cultivation, the extraction need can exceed 200 Liters per hour during critical periods (night).

3. The importance of associated air circulation

Greenhouse dehumidification cannot be optimal without homogeneous air circulation. Dry air must reach every leaf, even in the heart of the densest foliage.

• Break up microclimates: Leaves create a "boundary layer" of saturated air around them. Circulation fans break up this layer so that the dry air treated by the dehumidifier can do its job.

• Thermal equalization: Circulation prevents cold spots where condensation could form prematurely.

Why choose Climatik for your horticultural installation?

Working with Climatik equipment means choosing equipment designed for the extreme conditions of greenhouses (high humidity, dust, sprayed fertilizers).

1. Corrosion-resistant material: Our exchangers are treated to resist chemical environments and permanent humidity.

2. Precision regulation: Our systems can be controlled via high-sensitivity electronic humidistats or integrated into your central climate computer.

3. Proven profitability: By drastically reducing the need for fungicides and saving energy related to forced ventilation, our solutions pay for themselves in just a few seasons.

Our pro tips:

• Schedule your cycles: The humidity peak often occurs at sunset (temperature drop) and just before dawn. Anticipate by activating dehumidification 1 hour before these critical moments.

• Recover water: The water recovered by our dehumidifiers is almost distilled water. If stored properly, it can be reused for misting or watering sensitive plants.

Conclusion

Greenhouse dehumidification is much more than a simple comfort option: it is a strategic production tool. By controlling humidity, you provide your plants with an environment where they can fully thrive, while reducing your operating costs and ecological footprint.

Do you want to step up your game and secure your crops against humidity? Climatik experts are at your disposal to audit your greenhouse and propose the dehumidification system best suited to your yield objectives. With Climatik, cultivate performance with complete peace of mind.

Agri-TH-117 Sheet: https://calculateur-cee.ademe.fr/pdf/display/17/AGRI-TH-117