Futureproofing a new hortensia greenhouse in Amstelveen, Netherlands

MAY 2020

The construction of the new greenhouse at Meerlandenweg in Amstelveen is well underway. “The roof has just been closed,” says grower Bartjan Kolk, referring to the recent sealing of the greenhouse. This allows the installer Huisman Scherming to begin installing the climate screen systems.

“We’ll be working on that for about four weeks. Then we’ll disappear for a while and only come back two weeks before everything starts to install the screen cloths,” explains Dave Boer, sales manager at the installation company from De Lier. And what about the impact of the coronavirus crisis? “It’s still a dream coming true,” says the ambitious Bartjan

It was only a matter of time before Bartjan would be bought out of his location at Legmeerdijk, where he currently has 23,000 square meters of glass. “We sit right on the edge of existing residential development and under the flight path of Schiphol airport. This is literally the last piece of land where houses can be built.” Three years ago, a project developer approached him with an offer, and Bartjan was ready for the next step. By chance, two streets over on Meerlandenweg, space became available for new construction. Bartjan seized the opportunity. He is now in his final year growing hydrangeas at the Legmeerdijk site and expects to move to the new location by the end of the year.

Bartjan previously built a new greenhouse eight years ago, and the lessons he learned then have been invaluable in this new project. “Time is your friend, I’ve learned. You can only do it right once. That’s why I took my time in the preliminary phase.” Bartjan leaves nothing to chance. With the help of a consulting firm, he gathers broad information. “I want to understand everything. For example, I dove into AutoCAD myself so I could understand in broad terms what my suppliers are drawing. Not to have a say in everything, but to understand and make smart decisions.” He regularly brings together the greenhouse builder and various suppliers to align plans. “My goal is that when I walk into the greenhouse, everything fits and everything is neatly finished.”

The choices made

Huisman Scherming also contributes significantly to the total solution. Dave explains: “We install both screen drums under the bottom screen cloth. That is not a standard execution and requires adjustments to make it work. We coordinate that with the consulting firm and the greenhouse builder.” This choice stems from Bartjan’s desire for a narrower cavity, which provides better insulation. “I had been interested in such a narrow cavity for a long time. Dave came up with a clever solution by placing the tie rods through the drums under the cloth,” Bartjan explains.

Three types of Svensson climate screens are installed in the new greenhouse, Dave says: “The Luxous 1547 D FR and Harmony 4647 FR as horizontal upper screens, and Luxous 2945 R FR as facade screens.” Bartjan adds: “The screens are very similar to what I have now. The Luxous screen gives more diffuse light than the current LS 10, which is nice. In spring I want to start the morning with 80 percent lower screen coverage, and by midday the Harmony screen will be closed at 80 percent. We eliminate the gaps by overlapping the two screens.”

According to Dave, the improvement over his current screen installation lies mainly in the applied technique. “There are several screen layers above each other, creating the narrow cavity Bartjan so strongly wanted. And that is good for energy savings.” The installation method has also been improved. “We use, among other things, enhanced drum bearings and larger reversing wheels for reliable and longer service life of the installations.” Dave notes that the technical installations for the screens are being installed over the next four weeks in the new greenhouse. “Only at the very last moment, just before cultivation begins, are the screens installed to prevent contamination of the screens.”

The collaboration

Quality and innovation are what Ko Kolk Hortensia’s and Huisman Scherming have in common. Both parties consider themselves specialists in their field: one in screen installation, the other in production and breeding of hydrangeas. The connection between Bartjan and Dave occurred quickly. Dave explains: “Bartjan is clearly interested in technology. That works well. That way we can really spar with each other.” Bartjan agrees about the smooth collaboration and adds: “Dave listens and thinks along. He comes up with clever, well-substantiated solutions.”

The impact of corona on the project

Construction of his new greenhouse at Meerlandenweg was in full swing, and he had just started his final growing year at the Legmeerdijk site when the coronavirus outbreak began. Bartjan himself also became a victim of the virus. Fortunately, he has fully recovered. “I went on winter sports in week eleven.

At that point things were already creaking and cracking in the Netherlands. I thought: there goes my last growing year.” The diligent 40-year-old grower from Amstelveen immediately came up with a plan. “Within a week I decided for myself: keep costs low and do whatever you do as well as possible. Don’t spend money on cutting away useless shoots, but only bring the best to the market.”

He therefore focused on a limited part of his crop and cleared a quarter of his business. He now uses that space for the new cultivation that will soon be in his new greenhouse. “I’m already investing now to get off to a flying start later. That turns a necessity into an advantage.” Bartjan is confident the market will recover. “I can’t imagine the market completely disappearing, that simply doesn’t exist. Purchasing power will naturally return. Flower shops will naturally open again, people will get married again, and airplanes will fly again.”