VENLO, THE NETHERLANDS -- In their beds, the salad greens enveloped by magenta hues from the lights above hardly seem appetizing. Surprisingly, the unblemished leaves taste pretty good when they come out from under the lamps.

Those who visit Brightbox, a high-tech horticulture lab in the Netherlands' agricultural hub of Venlo are invited to taste what is grown under light-emitting diodes, or LED lights.

The salad greens are raised in such immaculate conditions, there is no need to wash the leaves before sampling, visitors are told.

"We try to stay away from soil," said Gus van der Feltz, global director of City Farming at Philips Horticulture LED Solutions.

He touts climate cells as the future of food production because the method relies on a fraction of the water needed to raise crops in fields or greenhouses. And plants grow faster under red and blue lights than the full spectrum of sunlight.

The research facility is a partnership between HAS University of Applied Sciences and the Dutch lighting giant Philips Royal.

The Netherlands is the second biggest exporter of agricultural products after the United States, and a leader in greenhouse technology. So it isn't surprising that the Dutch are at the forefront of the new trend in agriculture: vertical farming, also known as city, urban or even warehouse farming. It is even being eyed for skyscrapers.

Part of the appeal of growing indoors is that crops aren't vulnerable to the extremes of weather. The dense configuration of the plants also makes their care less labor intensive, and potentially easier for them to be tended by robotic technology.

Plant factories are being touted as the sustainable solution to the problem of decreasing farm acreage and a rising global population.

Philips Horticulture LED Solutions and PlantLab, two Dutch companies that are leaders in the indoor technology, will be heading to Michigan next week as part of an economic delegation accompanying the Dutch King and Queen's historic visit to the state.

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One of Philip's clients is Green Sense Farms in Portage, Ind., which describes itself as country's largest indoor, commercial, vertical farm.

Michigan has begun to embrace this high-tech farming method. In Detroit, Artesian Farms and Green Collar Foods recently opened vertical farming operations, reported the Detroit Free Press. New Buffalo-based Green Spirit Farms designed and made the stacking shelves for Artesian Farms. Both GSF and PlantLab use LED grow lights made by Texas-based Illumitex.

For now, vertical farming methods are primarily used to grow leafy greens, strawberries and herbs sold for a premium at high-end grocery stores and restaurants, not food staples such as rice, corn or potatoes needed to feed the masses.

"It's truly in its infancy," said Chris Beytes, editor of the Chicago-based GrowerTalks and Green Profit magazines. "Vertical farming will never replace traditional field agriculture or proven greenhouse technology, which is extremely efficient. But it will have its place in congested cities, growing certain high-value crops."

Beytes was part of a contingent of U.S. journalists -- including MLive and The Grand Rapids Press -- that toured Dutch companies ahead of the royal visit to the U.S. next week.

In a former retail warehouse turned headquarters in the Netherlands' city of Den Bosch, PlantLab has created 16 growing chambers equipped with rows of tiny blue and red LED lights that shine above trays of plants.



Inside the locked chambers, PlantLab does R&D on plants. By playing with levels of light, climate and nutrients, the company says it can shift how plants taste and even their nutritional value. PlantLab creates plant recipes for its clients that can then be scaled up.

"We haven't come across a crop we can't grow," said Ard Reijtenbagh, chief partnership officer for the 40-person company. "The question is what is economically viable at this stage."

The company's founders began by developing mathematical models for growing plants in the 1990s. It wasn't until a decade ago they moved into building their first prototypes, and the first commercial project began in 2010.

Reijtenbagh says the company doesn't have any interest into moving into the politically complicated and potentially lucrative medical marijuana market.

Instead, PlantLab is focusing its attention on nutraceutical, pharmaceutical and cosmetic companies.

PlantLab has yet to be introduced to Amway, which does significant business in two of the categories, Reijtenbagh said. The West Michigan company also operates its European distribution center in Venlo, about an hour's drive from PlantLab's headquarters.

Reijtenbagh said he expected the PlantLab team to learn more about Amway during its visit to Michigan.

Agriculture will also be a theme of the delegation's stop in Chicago.

There, the Royal Couple will tour Gotham Greens' newest rooftop greenhouse, the largest rooftop greenhouse facility in the world. The South Chicago facility showcases Dutch products used in the growing process from the seeds and growing mediums to climate control and biological control.

The King and Queen will end their U.S. visit attending a lesson of "Sowing Seeds of Innovation to Feed Cities Healthier Food," at Gwendolyn Brooks College Preparatory Academy.

Shandra Martinez covers business for MLive/The Grand Rapids Press. Email her or follow her on Twitter @shandramartinez.