News » 08.07.2025 - NL: Early start for greenhouses during "tropical" weather
After a tropical night in the Netherlands, work in the greenhouses got underway early again yesterday. In some greenhouses, work is even continuing overnight to avoid the worst of the daytime heat. Yesterday was once again extremely warm, though a sea breeze and possibly heavy thunderstorms were expected to push the heat away later in the day. But how has the sector weathered the heat so far? Here's an overview.
The current high temperatures are quite exceptional. In De Bilt, it was only the eleventh time since records began that the temperature exceeded 35 degrees Celsius. In many places, it got even hotter. The editorial team at GroentenNieuws visited several greenhouses and recorded temperatures as high as 38 degrees Celsius on the thermometers.
Weeronline has compiled the figures. The highest temperature ever recorded in De Bilt was 37.5°C, on July 25, 2019. The second-highest was 37.2°C, measured on July 26 of the same year, followed by 36.4°C on July 24. Prior to 2019, the standing record was 35.7°C, set on July 19, 2006. This Tuesday now shares seventh place on the list of hottest days ever recorded in De Bilt.
At 11:20 a.m. on Wednesday morning, the temperature in De Bilt reached 30.2°C, officially marking the start of a heatwave. It's the first official heatwave since August 2022, when the heatwave lasted eight days, from August 9 to August 16.
In the greenhouses, thermometers are being checked frequently. The extreme heat once again highlighted the impact of Voltiris' solar panel system, currently being tested at the Delphy Improvement Centre. On Monday, at the peak of the day's heat, the temperature in the greenhouse equipped with solar filters was 3.4°C lower above the strawberry crops compared to the greenhouse without the filters.
Hidde Preidel of RedStar demonstrates how plants themselves contribute to cooling the greenhouse. He shares data from Monday to illustrate the point. While outdoor temperatures continue to rise toward the end of the day, climate data show that from around 4:00 p.m. into the evening, plant temperatures begin to drop, eventually falling below the outside temperature.
"This cooling effect, caused by transpiration, helps restore humidity levels in the greenhouse climate," he explains. "Especially by limiting vent openings toward the end of the day, the temperature inside the greenhouse can drop significantly. In fact, we saw greenhouse temperatures fall as much as 4 degrees below the outside temperature! That's an impressive cooling capacity, thanks to the plants themselves."
At Porta Nova, they've been busy harvesting heat in recent days. While outdoor temperatures reached 34°C on Monday, the greenhouse remained comfortably cool at 21°C, ideal conditions for their Red Naomi roses.
"Behind the scenes, our Climator system was running at full capacity," they report. "Not only did it keep the greenhouse cool, it also stored a record amount of heat deep underground. That same energy will be reused in a few months to sustainably heat our greenhouses during the cold Dutch winter."
On the hottest day of the year, the team at Kaaij Kwekerij was treated to a refreshing ice cream from IJsboerderij Boereiis, topped with fresh strawberries from fellow grower Fryske Strawberries. A well-deserved moment of cooling down during the summer heat!
Now that plants are reaching peak production, the last thing you want is equipment failure—especially in extreme heat. Still, Kwekerij Litjens faced a breakdown in their logistics hardware, with 20 tons of bell peppers still to go—right in the middle of one of the hottest days of the year.
Supplier Gearbox responded quickly, rushing from Maasdijk to the pepper grower to resolve the issue. Shortly after, the EasyX system was back up and running. The EasyX photographs every pepper on the conveyor and detects even the smallest defect on the fruit.
Another thing you definitely don't want: a malfunction in your screen system. Fortunately, Tom de Wit was able to fix that issue early this morning.
Besides ice creams, extra drinking breaks and additional sun protection also help, shares HS Tuinbouw Service.
Tomato grower Marc Groenewegen observes that during a heatwave, people tend to complain more than plants. He sees that his crop is quite resilient and, despite the high temperatures, he's doing everything he can to keep the plants comfortable by paying extra attention to moisture levels and ventilation.
Source: www.floraldaily.com
« Back