Grower profile:
Paul Jansen
Cultivation manager
Location: De Lier, The Netherlands
Greenhouse: Venlo, 12 ha
What climate is needed: Proper amount of light, not too low plant temperature, direct day-night transition.
Svensson's climate solution: A combination of outdoor, energy and blackout cloths and insect gauze. A complete solution for Rijnplant.
Rijnplant, a nursery specialized in propagating and growing potted anthuriums, is a family business with almost 70 years of history. Three screen cloths have been installed on and in the newest greenhouse of the Rijnplant nursery in De Lier. The right level of light for the potted anthuriums is achieved with the outdoor SOLARO 7530 OA E AW screen and the LUXOUS 1547 D FR energy screen.
"The cloths are closed based on the PAR light measurement inside the greenhouse near the plants," says cultivation manager Paul Jansen, responsible for the climate at the Hofzicht location. Both the current PAR light level and the total amount of PARSOM that the anthuriums receive per day are important for optimal management of the screen cloths. A second goal that is achieved by using the outer screen cloth is to lower the greenhouse temperature on summer days.
"After closing the SOLARO 7530 OA E AW outer cover, the temperature in the greenhouse drops by 3 to 4 °C - just like that". While making a round through the greenhouse, this lowered greenhouse temperature can be easily felt.
In addition to screening, the LUXOUS 1547 D FR is also closed at the end of the day (in the colder months) to save energy and maintain the plant temperature. "The challenge is to not close the LUXOUS 1547 D FR too late in the afternoon, in order to avoid condensation of the crops". To be able to control this optimally, a Pyrgeo sensor is used, which measures the upward radiation. When the weather is cloudy, the fabric closes later than when the weather is clear.
The OBSCURA 10070 FR WB+BW blackout screen cloth is used for two purposes. For technical reasons, the fabric is closed in the late afternoon to immediately switch from day to night. "Research has shown that this keeps the anthurium plants more compact and robust," explains Paul. By closing the blackout cloth when the assimilation lighting is on, the light emission rules are also met.
During the construction of the greenhouse the decision was made to use insect gauze for the air vents. The aim is to keep all possible insects out of the greenhouse. The major challenge currently facing the cultivation manager is to allow more light to enter the greenhouse, i.e. to screen less for the potted anthuriums. Allowing more light has an effect on temperature, RH and CO2 control. This practical research goes in small steps. Due to the long planting cycle of more than half a year, the effect of allowing a little more light is only visible to the plants at a later stage.
