Diffuse screens improve crop photosynthesis in summer vegetable cultivation

JUNE 2021

A 20-hectare, state-of-the-art greenhouse was built in 2020 as part of the YouYou Sino-Dutch Agriculture Park on Chongming Island, Shanghai. Designed as a semi-closed greenhouse and equipped with advanced climate systems, the facility supports year-round production despite challenging local weather conditions. The main crops grown are tomato, cucumber, pepper, and lettuce. YouYou is known for its commitment to supplying Shanghai consumers with approximately 30–40 tons of safe, high-quality vegetables every day.

Diffuse light supports summer vegetable cultivation

One layer of Svensson Harmony screen is currently installed in the greenhouse.

“Summer has just begun in Shanghai, and shading is necessary to control excessive solar radiation. The light transmission of our glass roof is around 90 percent, so we use the Harmony screen to achieve the right shading level. For example, when growing cucumbers, we partially close the screen at around 650–700 W/m²,” says Leslie Qi, Deputy General Manager of Shanghai YouYou.

“We chose a diffuse shading screen because of how important diffuse light is for promoting photosynthesis and crop growth, especially for high-wire vegetable crops. Soft, evenly distributed light can penetrate deeper into the crop canopy, improving light-use efficiency. Direct light can cause plant burn, while diffuse light helps lower plant temperature. Using Harmony screens is a wise choice for both crop performance and for the people working inside the greenhouse during summer.”

Managing variable weather conditions

“Compared to northern China, winters in Shanghai are relatively mild, usually staying above 0°C. Our closed Harmony screen structure can therefore be used for energy savings at night,” Qi explains.

“The biggest challenge in this region is the hot summer. After about one month, we enter the plum rain season, which brings warm and humid conditions. During this period, we rely heavily on cooling equipment to maintain a stable greenhouse climate. This summer is especially important for us as we closely monitor climate control and energy consumption in our semi-closed greenhouse. We are fortunate to receive support from both domestic and international experts, including Svensson’s global climate specialists, particularly on screen management.”

Staying true to the mission

Agriculture has always played a vital role in YouYou’s development. Looking ahead, the company remains committed to increasing crop yield and quality through advanced horticultural practices. At the same time, YouYou takes responsibility for inspiring and educating the next generation of growers, nurturing a long-term passion for horticulture.