Belgian Grape Growers Sweat Through Heatwaves in Hot Greenhouses

Grape growers, known as 'serristen,' in Overijse, Belgium, are enduring sweltering conditions as they tend to their crops in heated greenhouses. The intense summer weather, with temperatures soaring, creates a challenging work environment under glass where oxygen is scarce. Currently, the delicate process of thinning grape clusters, a meticulous manual task called 'draineren' or 'knippen,' is underway. Koen Dewit of Druiven Dewit notes that while their larger greenhouses offer better air circulation than traditional ones, the temperature still averages 3 degrees Celsius higher than outdoors, describing the environment as a 'veranda.' To cope with the heat, growers traditionally whitewash the greenhouse glass with lime to block intense sun rays. Dewit also employs other strategies, such as misting the air with water and utilizing roof sprinklers, which cool the glass and lower the temperature. While warmth and sun are beneficial for the Flemish-Brabant table grapes, promoting sweetness, excessive heat is detrimental. Dewit observes that the current extreme temperatures are hindering growth, ideally preferring around 25 degrees Celsius. Despite the challenging conditions, the essential work in the greenhouses must continue as the grapes approach ripeness by late July or August.

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We have here larger greenhouses than the old traditional ones, so there is more space where the air can circulate. Nevertheless, it is on average 3 degrees warmer than outside; it remains a veranda.