Green Sense Farms of Indiana has signed a contract to build 20 vertical farms in China, with the latest due to open this week, said Robert Colangelo. "There are big opportunities there. It's a fantastic market," he added. "It's transforming from an industrial to a service economy and a lot of the land is contaminated. We have a good team who can build up a global network and can build in six months."
Countries "with a short natural growing season, long distances between growers and customers, and where water and pollution inhibit production" are the natural markets for such systems, he told Horticulture Week. "It's not a panacea," he pointed out. "It wouldn't work where there's a lot of bugs around. Food safety is a big concern. That could really set us back."
"We see a lot of farmers starting small, but when you start big you get the economies of scale and you can cover your overheads quicker. You need a minimum of two 100,000sq ft (9,000sq m) units to be viable. To maximise your advantage, it's all about location. We are putting these farms at distribution centres, which ensures they are at their freshest and most nutritious."
Explaining the technical challenges, Colangelo said: "At first, conveyance within the site was an afterthought, but now our first thought is where do the seedlings go in and the plants out? We design linearly. The trick is to automate to the right level based on crop costs and that's different in each country depending on its labour costs."
He identified training as a major demand for the sector, saying: "There is a shortage of people who know how to grow indoors." In a new $3m 2,000sq m vertical farm due to open in August in South Bend, Indiana, Green Sense will partner with the local Ivy Tech Community College in a training programme dubbed "Earn to Learn". "Colleges aren't cranking out the people we need so we thought we'd design our own training programme," said Colangelo.
A Green Sense partner for the past year-and-a-half, Dutch equipment supplier Ridder HortiMaX chief executive Joep van den Bosch discussed some of the technical challenges to efficient vertical growing. "People tend to put multiple crops in one grow room and expect a perfect product," he said. "With a mono-crop can you customise the climate and fertigation to it. Lettuce and herbs don't combine, though you can grow different types of each at the same time.
"Dehumidification is an even bigger issue in vertical farming than in a glasshouse. Plants are respiring all the time and you need to create vertical and horizontal air movement, ideally with the least amount of equipment. Analysing your data gives you the recipe for the next crop. Getting the water quality and nutrients right is easy initially, but harder in a recirculation system - you need a sensor and control element. Where there is water and light there will be algae, but do you need to disinfect every cycle or only at the end of the crop?"
On lighting, he added: "The right spectrum and intensity for the plant is a big issue, and a lot of research is still necessary. There is a big difference between suppliers."
Den Bosch University of Applied Sciences senior lecturer Jasper den Besten said: "We have compared full-spectrum against single-wavelength lighting on cavallo nero and found the yield a little higher with full-spectrum." He added: "Is it an expensive hobby? It costs 10 times more than a glasshouse, for which you would expect to pay around EUR500 per square metre, and is not as easy to make it back."
The Association for Vertical Farming (AVF) hosted an entire pavilion at GreenTech showcasing a range of technical solutions. Chief engagement officer Zjef Van Acker told HW: "This and the summit (see box below) show how fast the industry is growing. We see not just plant-growing but also aquaculture, mushrooms and even insect production being brought forward. Both mushrooms and insects produce CO2, which can provide enriched air for plant-growing, while insects are an input for aquaculture."
AVF UK representative Mark Horler added: "There are other urban growing projects coming through in the UK, particularly on the research side at universities. We aim to put people in touch with each other and we also have a programme of workshops."
In the pavilion, Urban Crops of Belgium presented its new FarmPro, an automated and climate-controlled growing room in a standard 40ft freight container. It is equipped with the company's tailor-made fixtures, with its tiered format giving 80sq m of growing area. Sales manager Gwen Dehaene said: "Climate control is via an app. You don't even have to be here. We are talking to retailers and restaurants about having these on-site." The company suggests medicinal plants and culinary flowers as possible crops, in addition to the now familiar leafy salads and herbs.
In the ever-more competitive area of LED lighting, Northumberland-based BSS LED made its first foray into the international horticulture arena. Co-director Steve Bell said: "We are new to horticulture but not to LEDs. We are electronics engineers and can do everything in-house, so rather than selling a standard product as the large manufacturers do, we can tune the wavelengths to what you need. Growers know it's the future but don't necessarily know the right wavelength mix. But if you can adjust that and the intensity, they are future-proof."
Exhibiting for the first time at the show was proving positive, he added. "A lot of people are looking for partners. We've been delighted."
Summit: Association of Vertical Farming awards prizes for top designs
The GreenTech show was preceded on 13 June by the Association of Vertical Farming Summit, which drew 260 international guests.
Here the $5,000 prize for the inaugural Vertical Farming Award was presented to Inter-Farm Market of Malaysia for its design for a vertical farm integrated into retail and community facilities within the same building.
In second place and winning $3,000 was VeGaN of the Netherlands for its vertical farming design for isolated countries such as Iceland, while IMPACKT Farm of Spain came third for its aquaponics design. In all, 100 entries were submitted from 24 countries.
The association is also investigating an international certification scheme.