Jul 14, 2020
CONTENT SOURCED FROM THE GUARDIAN
Written By: Jon Henley
On top of a striking new exhibition hall in the southern 15th arrondissement of Paris, the world’s largest urban rooftop farm has started to bear fruit. Strawberries, to be precise: small, intensely flavoured and resplendently red.
They sprout abundantly from cream-coloured plastic columns. Pluck one out to peer inside and you see the columns are completely hollow, the roots of dozens of strawberry plants dangling into thin air.
From identical vertical columns nearby burst row upon row of lettuces; near those are aromatic basil, sage and peppermint. Opposite, in narrow, horizontal trays packed not with soil but coco coir (coconut fibre), grow heirloom and cherry tomatoes, shiny aubergines and brightly coloured chards.
“It is,” says Pascal Hardy, surveying his domain, “a clean, productive and sustainable model of agriculture that can in time make a real contribution to the resilience – social, economic and also environmental – of the kind of big cities where most of humanity now lives. And look: it really works.”
Hardy, an engineer and sustainable development consultant, began experimenting with vertical farming and aeroponic growing towers – as those soil-free plastic columns are known – on his Paris apartment block roof five years ago.
This space is somewhat bigger: 14,000 sq metres, the size (almost exactly) of two football pitches. Coronavirus delayed its opening by a couple of months, but Nature Urbaine, as the operation is called, is now up and running, and has planted roughly a third of the available space.
Already, the team of young urban farmers who tend it have picked, in one day, 3,000 lettuces and 150 punnets of strawberries. When the remaining two-thirds of the vast rooftop of Paris Expo’s Pavillon 6 are in production, 20 staff will harvest up to 1,000kg of perhaps 35 different varieties of fruit and vegetables, every day.
“We’re not ever, obviously, going to feed the whole city this way,” cautions Hardy. “In the urban environment you’re working with very significant practical constraints, clearly, on what you can do and where. But if enough unused space – rooftops, walls, small patches of land – can be developed like this, there’s no reason why you shouldn’t eventually target maybe between 5% and 10% of consumption.”
Nature Urbaine is already supplying local residents, who can order fruit and veg boxes online; a clutch of nearby hotels; a private catering firm that operates 30 company canteens in and around Paris; and an airy bar and restaurant, Le Perchoir, which occupies one extremity of the Pavillon 6 rooftop.
Perhaps most significantly, however, this is a real-life showcase for the work of Hardy’s flourishing urban agriculture consultancy, Agripolis, which is currently fielding inquiries from around the world – including in the UK, the US and Germany – to design, build and equip a new breed of soil-free inner-city farm.
“The method’s advantages are many,” he says. “First, I don’t know about you, but I don’t much like the fact that most of the fruit and vegetables we eat have been treated with something like 17 different pesticides, or that the intensive farming techniques that produced them are such huge generators of greenhouse gases.
“I don’t much like the fact, either, that they’ve travelled an average of 2,000 refrigerated kilometres to my plate, that their quality is so poor, because the varieties are selected for their capacity to withstand that journey, or that 80% of the price I pay goes to wholesalers and transport companies, not the producers.”
Produce grown using this soil-free method, on the other hand – which relies solely on a small quantity of water, enriched with organic nutrients, minerals and bacteria, pumped around a closed circuit of pipes, towers and trays – is “produced up here, and sold locally, just down there. It barely travels at all,” Hardy says.
“It uses less space. An ordinary intensive farm can grow nine salads per square metre of soil; I can grow 50 in a single tower. You can select crop varieties for their flavour, not their resistance to the transport and storage chain, and you can pick them when they’re really at their best, and not before.”
No pesticides or fungicides are needed, no soil is exhausted, and the water that gently showers the plants’ roots every 12 minutes is recycled, so the method uses 90% less water than a classic intensive farm for the same yield. The whole automated process can be monitored and controlled, on site or remotely, with a tablet computer.
Urban farming is not, of course, a new phenomenon. The mayor of Paris, Anne Hidalgo, aims eventually to have at least 100 hectares of rooftops, walls and facades covered with greenery – including 30 hectares producing fruit and vegetables. A programme called Les Parisculteurs invites local groups to come up with suitable projects for up to a dozen new sites every year.
Inner-city agriculture is booming from Shanghai to Detroit and Tokyo to Bangkok. Strawberries are being grown in disused shipping containers; mushrooms in underground carparks. Not all techniques, however, are environmentally friendly: ultra-intensive, 10-storey indoor farms that have sprung up in the US rely on banks of LED lighting and are major consumers of energy, Hardy says.