CAN-Agri sheds new light on principles of vertical farming

“The truly sustainable indoor vertical farm shouldn’t be a compromise. The power of natural sunlight is essential,” says François. He notes that most ‘vertical farms’ are not truly vertical: “They are made up of horizontal layers stacked vertically, where the top layer blocks sunlight for the ones below. It’s a crying shame that we don’t make optimal use of natural sunlight.” This realization led François to pioneer a unique system where traditionally horizontal layers are rotated through 90 degrees. François explains: “This allows each plant to get the necessary light from a naturally occurring source: the sun.”

Optimal use of the sun

Living in South Africa, where sunlight is abundant, François saw a clear opportunity to rethink traditional farming methods. “Here in South Africa, we couldn’t understand why you’d use artificial light instead of sunshine. It’s such a waste of energy – and the sun is free!” CAN-Agri’s production facility in Pretoria reflects this philosophy. The facility comprises rows of vertical ‘plant walls’ spaced strategically to ensure that sunlight reaches each wall. François adds: “We recognize that some locations require supplemental lighting, but our goal is to harness solar energy whenever and wherever possible.”

Unique closed-loop water system

Besides saving energy by tapping into the power of sunlight, at CAN-Agri they also make smart use of their irrigation water. In partnership with Priva, they’ve developed a concept to safely reuse irrigation water and the valuable fertilizers it contains. This system pre-treats the water, doses fertilizers, and disinfects the irrigation water afterward.

The design phase was not without its challenges. “The water system at CAN-Agri is more complex than most. Whereas most growers largely have a monoculture with just one or two water storage tanks for their daily supply, at CAN-Agri they work with lots of smaller tanks,” explains Kees van der Kruk, Product Manager at Priva. “This enables them to adjust the nutrient levels and pH values based on the specific needs of whichever variety is being grown in a particular area of the greenhouse. Another advantage of this kind of modular system is that it keeps the drainage water from the various crops separate, which minimizes the risk of cross-contamination between the systems in the case of a waterborne disease.” To completely eliminate the risk of contamination, the Priva Vialux M-Line disinfects all the water from the storage tanks to kill all bacteria, viruses and other pathogens.

Optimizing production

The greenhouse technology includes an integrated Priva Connext process computer to keep the closed-loop water system and all the other processes running automatically, reliably and on schedule. The CAN-Agri solution places considerable demands on Connext in terms of process automation. Due to the large number of water storage tanks, the process computer is continuously calculating new priorities and making the necessary adjustments. “A fully automated irrigation process – from fertilizer dosing to pre-treatment and post-treatment of the irrigation water – gives growers more time to focus on optimizing production,” continues Kees.

The right people on board

François’s background as an architect played a key role in designing this innovative system. His lack of prior horticultural experience became an advantage. François says: “My construction expertise was invaluable for this project. I’ve also brought the right people on board to build on our vision.” Over the past four years, CAN-Agri has refined its concept to a commercial scale. “Our research has given us deep insights into what works, what doesn’t, and where we can improve.”

CAN-Agri’s next step is to scale its technology worldwide. François emphasizes: “Our solution isn’t a ‘farm in a box.’ Each project is unique, so we prioritize a thorough advisory phase to assess factors like labor, water, and energy costs. This ensures our model is financially viable. We see ourselves as a service provider, collaborating with customers, our R&D team, and technology partners like Priva.”