Vertical farming is a way of taking the controlled environment of a modern commercial greenhouse to the literal next level. By stacking plants vertically on shelves or tall pillars, vertical farming allows 10 times the yield for a given land area.
Plants are grown in completely enclosed conditions, with LED lights replacing sunshine and closed-loop water recycling. There is no need for pesticides, since the indoor space is already free of bugs, and plants can be grown in such clean conditions that there is no need to wash them before eating.
A vertical farm can fit the equivalent of 280 hectares (700 acres) of farmland in a building the size of a large supermarket, and by manipulating the artificial day length and season, it can harvest crops all year round.
Intensive indoor agriculture suffers from high start-up costs and energy bills, but recent advances in increased efficiency and lowered manufacturing costs of LEDs have begun to make vertical farms more cost-effective. It currently only makes sense for certain crops though.
Salad leaves and strawberries are small plants with large profit margins, but cereal crops – like wheat and corn – are too tall to stack efficiently and have a much lower value per tonne. A loaf of bread made from vertically farmed wheat would cost around £18, just for the electricity to power the LED lighting, according to a study at Cornell University.
Solar panels on the roof and walls of the building are not enough to make vertical farms self-sufficient. But indoor agriculture allows farming to be integrated directly into cities, reducing food miles. It is more efficient to transport electricity from rural solar farms to a city and grow the food close to where people live. This closed-loop growing cycle could be much less polluting to the environment too, and may even be the answer to supplying human settlements on the Moon or Mars.
Asked by: Rich French, London
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