Last winter a HARMONY 7247 FR diffusing screen was installed in the new greenhouse at the Zamioculcas nursery of Mart van der Voort & Zn. Mart had initially opted for an aluminum screen but then his installer informed him about the Harmony screen. Thinking, “No harm in trying”, Mart had the light-diffusing Harmony screen installed.
After a few months, the grower is extremely pleased about his decision, “The climate in the section with Harmony 7247 FR feels cooler and more pleasant on hot days.” This is confirmed by graphs on the climate computer: on sunny days the temperature under the Harmony is an average of 1°C cooler than the control group section with an aluminum screen. This fact is even more significant as the Harmony section visibly lets more light through than the control group section: 70% light blockage compared to 80 - 85% blockage. This high light blockage of 80 - 85% is achieved by a PH77 screen plus a layer of chalk on the greenhouse cover, which is applied in April.
Thanks to Harmony’s light-diffusing features, it was not necessary to chalk this greenhouse. Another result of the comparison: the Zamioculcas pot plants under the Harmony clearly have more stems, which also develop faster and more uniformly. For example: the 10-week-old Zamioculcas plants growing in the Harmony section are almost as large as the 15-week-old plants in the control group section with PH77.
On the left the Harmony 7247 FR and on the right PH77 - notice the difference in light transmission
Zamioculcas cultivation is a specialised and rather slow process. The growing process takes an average of 26 weeks. The closing of the screen is not connected to any specific solar radiation but rather is done based purely on the grower’s experience and skill. Mart says, “I close the screen after I’ve felt the climate in the greenhouse and seen the plants.”
The LUXOUS 1547 D FR is installed on a second wire system. This screen runs in the opposite direction to the Harmony screen situated above it. In the summer the energy screen is closed by 1 meter, to shield the ventilation gap from the Harmony. In winter the energy screen is often closed, 24 hours a day is not unusual. The goal of this is to save energy and create a more humid climate through less piped heat. At night the Harmony screen also remains closed in order to save as much energy as possible.
Mart sums up by saying, “The climate feels so nice under the Harmony screen, and the plants do well in it. If I had to choose over again right now, it would be a Harmony screen again.