How to tackle condensation in a greenhouse: understanding the risks and finding effective solutions.

Condensation in a greenhouse is a common issue faced by many gardeners. Excessive humidity can lead to plant diseases and damage to structures, making it crucial to understand the reasons behind this phenomenon and how to address it. “Women’s Advice Blog” discusses the primary causes of condensation and effective methods for eliminating it.

What is condensation and why does it occur in a greenhouse

Condensation is the liquid that forms when water vapor transitions to a liquid state due to a drop in temperature. In a greenhouse, this process intensifies when warm, moist air comes into contact with cold surfaces (walls or roof). Since the temperature inside the greenhouse often differs from the outside, condensation readily forms, especially in the morning after a cool night.

The main causes of condensation include:

• insufficient ventilation – the lack of optimal fresh air intake contributes to high humidity levels. Low efficiency of exhaust systems also exacerbates the situation;
• overcrowding of plants – excessively dense planting leads to moisture stagnation and increases humidity in the greenhouse;
• temperature difference – when the first rays of sunlight hit the cold walls of the greenhouse, a significant temperature difference occurs, resulting in water droplets formation;
• moisture from plants – during respiration, plants release water vapor, which can also condense on the walls and ceiling of the greenhouse;
• temperature fluctuations – in winter, when it is cold outside and warm inside, condensation accumulates due to high humidity levels indoors.

How condensation impacts plants

Excess moisture is harmful to plants, as it promotes disease development and can even lead to crop loss. Dripping condensation on plants causes them to become oversaturated with moisture, which settles in the soil. Additionally, moisture accumulation can facilitate the spread of pathogenic microorganisms, increasing the risk of diseases.

How to combat condensation in a greenhouse

Ventilation

Periodically opening windows or vents is the primary method for addressing elevated humidity. It's important to ensure air circulation through proper placement of openings, such as on the ceiling and walls. It is recommended to start ventilating when the temperature difference inside and outside reaches 10°C.

Double film

Stretching two layers of film allows condensation to be trapped between them, preventing water from reaching the plants. However, this method does not reduce the humidity level inside the greenhouse, as moisture does not evaporate.

Hydrophilic film

This special film prevents the formation of large droplets by evenly converting water in the film into a water layer that drains into the soil. This helps maintain the transparency of the film for sunlight penetration without increasing humidity levels inside the greenhouse.

Ventilation systems to combat condensation

Mechanical ventilation

Mechanical ventilation systems involve manually opening windows and doors to regulate temperature. This is the simplest and most economical method.

Automatic ventilation

Automatic systems use fans and temperature sensors that allow for maintaining an optimal climate inside the greenhouse without human intervention.

Hydraulic and bimetal systems

These systems open or close vents depending on the temperature, effectively controlling humidity and temperature without the need to manually adjust ventilation.