Growing food in the dark

A new initiative by Tokyo Metro is using the uninhabited underground space between stops to implement hydroponic farms. The produce they are growing is sold onto neighbouring restaurants and eventually they would like commuters to consume their yield through salads and smoothies. Repurposing these forgotten spaces raises the question of how we can create and sustain micro climates for food production and how that can change the way we live – and at what level.

From the subsurfaces of a city to low Earth orbit, emerging farming technology is changing the way we grow, so as it can be controlled to maximise yields and minimise waste. Many aspects of earthling life are dependent on the basic mechanics of photosynthesis and one limiting factor of growing food is undoubtedly access to light. With the advent of LED light systems this is becoming a problem of the past.

The ability to utilise dark spaces for food production doesn’t only exponentially expand our possible surface area for farming, it can also see humanity sustained in deep space missions in the future. NASA has embarked on one such an endeavour through an experiment dubbed Veggie, carried out aboard the International Space Station that saw astronauts growing lettuce in space. After several years of development, in May 2014 the first growth experiment took place in an LED-powered plant where astronauts grew the first “astroponic vegetables”.

Using an incubator rigged with LED growth lamps (to replicate natural sunlight), the lettuce took root in planting pillows sent to the station, containing lettuce seeds, fertiliser and clay. The LEDs were tuned to the red and blue portions of the visible spectrum that plants would use for photosynthesis. Interestingly, the green LEDs were not as useful in emitting much light, however they were included for the sake of aesthetics, so as the lettuce didn’t turn out as “weird purple plants”!

Contrary to what the researchers anticipated, the roots of the seeds did not grow in all directions in the absence of gravity. The plants instead used light to signal a hierarchy of which way to grow and which direction to send their roots. NASA found that a gradient of light gave the most efficient guiding signal to the seed in knowing how to grow. Diffuse light, for example, was not as efficient – somewhat confusing the direction. Most importantly, these experiments revealed how plants process signals in adverse environments and how they ‘read’ light.

Once grown into fully matured plants, the lettuce from the first onboard experiment in 2014 was not eaten, but flash-frozen and sent back to Earth for comparison to an identical experiment carried out at the Kennedy Space Centre. Since being found as safe for consumption, in August NASA posted a video of Expedition 44 astronauts Scott Kelly, Kjell Lindgren, and Kimiya Yui nibbling on the spoils of their efforts. This marks the first fresh food production system in space.

The aim of these experiments was to observe how we could grow food off the surface of the earth, where no terrestrial organism has ever been before. Interestingly, NASA found that the easiest way to cultivate plants was to transport them in the form of seeds. Research Robert Feri described seeds as the “dormant storage life form of plants”. Seeds are the ultimate package in which food can be transported, you can “freeze them, you can put them in the dark” and what you need to activate them is light.

These first experiments in light are giving shape to possible ways that we may sustain a population of the future on a global scale. Growing veggies in unusual places has many implications for our society, whether we remain grounded on Earth or venture beyond our borders into outer space.