High temperatures under screen requires venting:
"Netherlands: "The more assimilation lights, the more problems"
A 70.000 lux (ca. 690 micro mol) installation. Source: Agrolux
In the Netherlands, on April 1, the dark period changes and until May 1, from a half hour after sunset to 02:00 A.M., no light may escape the greenhouse: a minimum of 98% reduction is required. "If the temperature stays like this, it's no problem," says Mario. "But when the temperature increases in spring, problems arise. It is too hot under the screen cloths and venting requires a lot of energy and has much influence on climate management inside the greenhouse."
A 70.000 lux (ca. 690 micro mol) installation. Source: Agrolux
The problems with the dark period increase because the amount of light in the greenhouse is also higher. "In the dark period, light so is important that growers install more lamps, making the temperature in the greenhouse higher. The screens are getting better, in the sense that they are more permeable to heat, but closing them remains difficult." Growers with exposure above the 15,000 lux, are forced to keep them closed throughout the night. According to Scherpenzeel this should always be combined with climate control, possibly derived from the New Cultivation. "Otherwise, it simply won’t work."
For more information:
Nobutec Quality Screen
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06-1966 1162
