Data-driven screening decisions for optimal growth

An intelligence plastic greenhouse project which was built by Breasion started production in March 2019. The greenhouse is located in Malong, Yunnan, 2 ha in total. It is a modern nursery which equips with heating, irrigation, screen systems, etc, everything is automatically controlled by computers for beautiful rose flowers.

Full of curiosity and passion for modern flower cultivation, the Greenhouse owner Wu Qian, stepped into this new world from the finance industry. He accumulates his own knowledge and practical experience by analyzing data and continuous learning of the potential of greenhouse climate tool and plant empowerment practice.

The problem: Highly variable Yunnan climate creates big challenges for rose cultivation

Due to climate change snow is more frequently seen in the north part of Yunnan in winter. It has become a big challenge for rose cultivation in non-heated plastic greenhouses.

Solar radiation is always the predominant natural resource in the Yunnan region. If greenhouse temperature and humidity can be maintained well in winter, the light level is ideal for rose growth. However, from March, the daily max light intensity can exceed 850-900W/m2 and too strong radiation will affect crop quality. 

The heat brought by the sun will be accumulated in the greenhouse. In May, when there is no active cooling available, a temperature peak over 30℃ easily reached noon or afternoon and RH will be lower than 40%, which will result in plant stress.

The solution: Greenhouse climate technology and double climate screen solution

Based on the knowledge and principles of Plant Empowerment two-layer of different Svensson screens were installed for energy-saving and shading., after advisory on the specific greenhouse situation.

In order to control light better, Qian invested a PAR sensor in the greenhouse together with the outside radiation meter. With the PAR sensor, the real light level which reaches the crop is known and the accumulated PARsum as well.

The result: Optimal temperature and light based on data

With help of the Harmony screen, the temperature can be relieved, and the RH will not drop down further. And what is most important is that the soft and homogenous light will benefit plant yield and quality.

With help of the thermal screen, we can effectively hold sun energy in the greenhouse to maintain a higher temperature. Two closed structure thermal screen in Qian’s greenhouse can be both closed on a winter night, it can help save more energy when heating is on. Besides, Luxous screen can be closed in cold winter daytime due to high light transmission. The night temperature in February and March can be lower than 5℃, the thermal screen is vital for maintaining a stable climate. Through data analysis, Qian and Svensson climate consultant summarized some tips on managing screening and ventilation to balance temperature and humidity. These valuable experiences will for sure be used in the new season.

“With the PAR light data, we can adjust the screening strategy based on crop needs. In March, we started to shade with Luxous which has a lower shading value. Following the rise of light level, we combine different percentage close of two-layer screens for shading flexibly and try to prevent light loss caused by higher shading value of the screen.”  Qian says.

“Combining data analysis and crop situation, we can find out what is the problem and adjust the climate tools. For screening, we can try many settings and consider the relationship with other equipment because these will directly influence the climate. After all, we should focus on the plant need to increase crop yield and quality.” Qian added.