by Amber

World’s Largest Wall Farm

Outdoor hydroponic farming took place in a big way over the 2015 growing season in Milano, Italy. Some call the wall farm a “green wall,” and green it is, showcasing American innovations in growing food on the east wall of the U.S. Pavilion at the World’s Fair. The theme this year was feeding the planet, and the United States exhibition was called, American Food 2.0. Along with techno food production U.S. style, attendees were introduced to the American phenomenon of the food truck with mobile chefs featuring harvests from the hydro wall in the menus. There was also a James Beard restaurant on the roof serving all manner of gourmet fare.

The farm grew everything from wheat to heirloom kohlrabi using hybrid hydroponics in panels of ZipGrow Towers above the heads of pedestrian traffic spanning the length of a football field. What’s hybrid hydroponics? It includes soil to help retain water and nutrients, which is only possible with a drip irrigation system.

The panels in the farm wall were designed to rotate to give the crops the best sun exposure, and allow better airflow to the interior. The 1494 towers were planted with over 10,000 heirloom plants in forty-two seed varieties that came from Baker Creek Heirloom Seed in the US, and were started locally in Fino Mornasco by Peverelli Farm and Floricoltura Pironi nursery.

While Baker Creek collects their seed offerings from all over the world, many of the varieties that arrived at Floricoltura Pironi for starting presented the seasoned grower with new challenges. They had never grown these kinds of plants before. There were failures in germination with some of them, as can be expected when trying to grow something totally foreign to you, but Andrea Pironi overcame the obstacle, and was successful in supplying all the crops planned for the wall farm. The experience has given her a new array of exotic food plants to offer her customers, many of them chosen for the exhibit for their richness in dietary nutrients.

While the 9,250-square-foot (860-square-meter) growing wall held 10,000 plants, it took over 100,000 plants to keep it looking fabulous and maintain high production. Floricoltura Pironi grew more than 130,000 seedlings for the pavilion project, which were grown with mycorrhizae in a close to organic program. Close to? The nursery’s website reveals that they use a special extract made from beets, sugar cane, and other plants as a development booster, which allows them to reduce the amount of chemical fertilizers by 50%, and produce their specialty crop… fruit and vegetable plants for home gardeners and small farms that are amazingly robust, and always heavy fruiting with an exceptionally great tasting harvest. They do use pesticides when absolutely necessary, and the organic option whenever possible to maintain plant quality for their customers.

A vertical farm of this size that’s growing so many types of plants is a big job, and complex too. The towers were assembled and planted at Peverelli Farm where they were also grown to a certain stage of fullness before being installed on the farm wall. It was the farm staff who have maintained the plants and hydroponic system since the wall was assembled prior to the fair opening in early May. Unlike the backyard garden or market farm, this was a display that had to look awesome continually, so it makes sense that maintaining the beauty of the green wall meant swapping out those things that would detract from it’s aesthetic value. Different panels of plants were watered and replanted on different schedules depending on the variety of crop grown. One greenhouse worker liked the peppers best, because those plants could remain on the wall for a full 6 weeks.

The crops were harvested 5 times during the fair which ends with October. Over 5 million visitors have investigated the USA Food 2.o experience as of last week. It’s interesting to note that there is a discrepancy on just how big this farm is. The media reports that it covers 7,200 square feet, while the official pavilion site states that it’s much larger at 9,250 square feet. Who has been misinformed? Not sure, but it’s still massive, regardless of where the typo is.

While the indoor gardening and urban farming crowd is highly aware that feeding the world in the future will be easier with vertical farming, the architect of the USA pavilion only included it after some enlightenment. The farm wall was created with ZipGrow Towers after Nate Storey, inventor of the hanging grow system and CEO of Bright Agrotech convinced him that the future of agriculture is in vertical farming. Dr. Storey made several trips to Milano to get the farm wall up and running, and to check on it’s progress. He also returned in early October to do a presentation on the merging of organic farming and technology. Nate’s farm in Wyoming grows organic food for market year around in blustery Laramie using aquaponics and the grow towers he invented.

So, exactly what crops were they growing in the world’s largest outdoor vertical farm? Get more information at: USA Pavilion 2015.


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The garden played a starring role from spring through fall in the house Amber was raised in. She has decades of experience growing plants from seeds and cuttings in the plot and pots.