This is exactly what's happening at a Dutch cucumber grower and a tomato greenhouse, saving the growers 90% labor.
These companies are working with the Plant Elevation System (PES). PES is an invention of Atgrow, which in turn is part of Vullings Metaalbewerking en Systemen. This Dutch company, which also produces irrigation systems for mushroom cultivation, developed their first lowering system for the horticulture industry a decade ago. "We developed a system to place at the top of the greenhouse. It had a few disadvantages," director Jan Arts says. "You had to install a complete construction in the greenhouse. That's expensive and blocks out too much light." The way it worked wasn't ideal either: because the plants didn't grow uniformly, they couldn't all be lowered at the same time. "For us, after the first system these things were absolutely necessary before entering the market. The past 8 years, we developed no less than ten systems together with an engineer – and threw nine of them out the window. Now we have a system we can fully get behind: the Plant Elevation System."
"It's not a 100% replacement for labor," he continues. "You have to go through it again, for an extra top, or to unroll the pulley a bit more if the plant grows more. But it easily saves 90% of the time needed for lowering." And the system turns out to have even more advantages. One of the growers who works with the system, takes into account the ideal working height for his employees when determining the height of the plants. He then divides his employees across the nursery according to height. "That saves another 15% of labor," Arts calculates. The final, unexpected advantage, is in plant health. "It seems to be a lot better for the plants to do the lowering at night," Arts continues. "The plants have less stress, because the lowering occurs gradually, and can be done when the plant is in rest. This leads to higher yields for the grower."
According to the calculation, the system can lead to improved yields by saving labor for lowering the plants (ca. 90%) and as a result of harvesting at the ideal height (ca. 15%). Atgrow will commission research into the gain regarding the lower stress levels thanks to lowering at night. "All in all, we expect the payback period for tomatoes to be less than three years. For cucumbers, there's more labor involved – then the investment should be recouped within 1.5 to 2 years."
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