Why screen systems are essential for an optimal greenhouse climate

Growers face a major challenge: poly greenhouses increasingly struggle with high humidity and temperature fluctuations, leading to crop stress and lower yields. Research by Wageningen University & Research (WUR) shows that screen systems are the key to achieving a stable greenhouse climate. By actively controlling humidity, light, and temperature, crop production can increase by as much as 25%. In this article, Rob Bekkering and Sander Zwinkels from Van der Valk Horti Systems emphasize the importance of screen systems.

Challenges in maintaining an optimal greenhouse climate
Currently, excessive humidity in Spanish and Portuguese poly greenhouses is a major issue. When humidity levels rise too high, the risk of fungal diseases and pests, such as the harmful Thrips parvispinus, increases significantly. It is therefore crucial to be able to reduce humidity in the greenhouse when the situation demands it.

Temperature control is equally essential for optimal crop results. "Plants are sensitive to stable growing conditions," says Sander Zwinkels, Senior Project Manager. "Sudden temperature fluctuations cause crop stress, increase disease pressure, and reduce yields."

Screen systems: take control of your greenhouse climate
Screen systems offer a reliable solution to these challenges. "Screens are adjustable and give growers direct control over their greenhouse climate," explains Rob Bekkering, Commercial Manager at Van der Valk Horti Systems. "They allow growers to intervene at any time and adjust conditions based on changing weather. For example, screens can be opened when humidity is too high to improve ventilation, which helps reduce condensation and lower overall humidity."

But screens do more than manage humidity, they also optimize light distribution. A great example is PARperfect, a combination of multiple screen fabrics that ensures uniform light distribution and a constant light level. This increases photosynthetically active radiation (PAR) by 30%, enabling crops to make the most of available light.

"Screen systems also help regulate temperature. You can retain heat during cooler periods and reduce heat peaks during hot spells. This prevents plant stress and protects crop heads from burning," Rob adds.

© Van der Valk SystemenRob Bekkering and Sander Zwinkels from Van der Valk Horti Systems

WUR confirms higher crop yield per m2 with screen systems
By actively managing humidity, light, and temperature, screen systems can deliver up to 25% higher crop yields. This is supported by a study from Wageningen University & Research (WUR) that investigated the impact of screen systems on crop yield in a Spanish poly greenhouse. The study shows that screens can increase PAR light by 30%

and effectively reduce humidity. This combination helps to create a more stable greenhouse climate and results in a yield increase of up to 25%.

Rob emphasizes that screen systems are a must-have for every grower. "They directly contribute to higher yields per square meter. By creating an optimal greenhouse climate, crop production can increase by as much as 25%. That means the same area produces more, reducing labour costs. So, with a relatively modest investment, you can achieve significantly higher returns."

Suitable for any poly greenhouse
"Last year, we supplied screen systems for a total of 60 hectares of poly greenhouses," says Rob. "This year, that number has tripled to 180 hectares. This not only indicates the growing demand for screen systems but also shows that growers increasingly recognize screens as a strategic investment for creating optimal growing conditions."

Van der Valk Horti Systems offers tailor-made solutions for any type of poly greenhouse and screen fabric. "Thanks to our large in-house R&D team, we can also support specific challenges and develop innovative solutions," says Sander. "It's important to note that our screen systems can be installed without drilling, welding, or other invasive modifications. This keeps the greenhouse structure completely intact."

Learn more about how screen systems can increase crop yield and get in touch with Rob Bekkering.