(CNN) — The fields around the Spread factory in Kameoka, a satellite town west of the Japanese city of Kyoto, are scrubby and barren -- the farmers there have long since harvested the rice ahead of winter.
While it doesn't generally get too cold in this part of Japan, the temperature drops enough to halt crop farming for four to five months.
Inside the doors of the eerily high-tech facility it's business as usual, as masked workers glide around quietly but purposefully. They'll see 21,000 heads of lettuce shipped out across the length and breadth of Japan today, all delivered to supermarkets and restaurants within 24 hours of leaving the doors of this vertical farm.
They'll see a further 21,000 the following day, and the day after that too -- 7.7 million a year in fact.
Spread harvests 21,000 heads of lettuce a day.
Marrying agriculture and industry
Spread is Japan's largest vertical farm, a unique blend of agriculture and industry, and its Kameoka factory grows and ships out produce -- for now four varieties of lettuce but potentially any kind of leafy vegetable -- year-round.
The company is set to more than double its output with the opening of another western Japanese site early in 2016.
"Around the world we're facing increases in population and more and more environmental issues for farming," Shinji Inada, president of Spread, told CNN.
"As a company we feel we need some new agricultural systems in order to survive and ensure the future for the next generation."
Sprout was formed as far back as 1992, but has since grown into one of the most advanced and efficient vertical farms in the country, if not globally. Inada claimed it's the largest producer in the world and indeed, the first to mass-produce vertical farming.
Growing time, from seed to harvest, is a lean 40 days.
Sustainable, safe food source?
The company's mission is to "continually work towards the realization of a sustainable society while protecting the environment through the use of food technology for the comfort and safety of our children and of future generations."
It hasn't been an easy ride. Initially, said Inada, people were suspicious of the product, given that its far removed from traditional farming.
"In the beginning people reacted to our product as something unnatural -- machine-like -- but by continuing to sell in the supermarkets people started to realize slowly that the taste was good and there were health benefits, so we slowly gained customers.
"The turning point was the incident in 2011 at the Fukushima nuclear facility. After what happened there, people became more aware of the importance of safe food and it kind of turned the tables for us."
Vertically-farmed vegetables have significant health advantages, not least because they require no pesticides. The factory itself is spotless, with workers in the growing rows and in the packing facility fastidiously covered up. It is more reminiscent of a microchip factory than a farm, but the payoff is that each head of lettuce is so clean that consumers could eat it straight out of the bag.
Cleanliness is paramount in the facility, which uses no pesticides on the crops. Workers wear full-body suits and masks to maintain the environment.
Improved growing efficiency
The growing cycle is a lot faster than out in the elements too, with lettuce ready from seedling to picking in 40 days, as opposed to an average of two months in a regular outdoor farm. Prey to the vagaries of the weather, traditionally-grown lettuce is also highly sensitive to price fluctuations; not a problem when you know what the climate is going to be day in, day out.
The new facility, which opens its doors in a custom-designed building in the science park area of Keihanna in 2016, is going to be much more highly automated than Kameoka. They'll be able to recycle 98% of the water at the new site, and with increased automation will be able to cut down 50% of their current factory's labor costs, said Inada.
Despite working towards a fully-automated facility, Inada doesn't feel that we'll be getting served all our vegetables by robots in future.
"I don't think vertical farming will take over the whole farming industry," he said. "I still think seasonal and local vegetables are very important and unique and is something to embrace.
"Our business and existing farms have to cohabit together. If you think about the global food situation there is a need for this kind of farming."