Hydroponics is a water-based, soil-less way of cultivation. People can grow food in places where traditional agriculture simply isn’t possible such as arid, rocky, snow-bound and dense urban areas.
Food is made available to a city by land, sea and air from across a huge hinterland which spans the globe. Over 60 per cent of the human population now lives vertically in cities. The time has arrived for us to transform our traditional techniques of growing food. Vertical farming (VF) is now envisioned as a solution to maladies afflicting agriculture by scientists at Columbia University.
The vertical farm project was conceived as a response to increasing pressures of diminishing land resources and fast-changing climatic conditions to reliably produce food at reasonable financial and environmental costs to fulfil global food demand for a conservatively-estimated world population of 9-10 billion by 2050.
The idea is simple enough. Imagine a 30-storey building with glass walls, topped off with a huge solar panel. On each floor there would be giant planting beds, indoor fields in effect. There would be a sophisticated irrigation system. And so, crops of all kinds and small livestock could all be grown in a controlled environment in the most urban of settings without soil. The idea of vertical farming was first proposed 11 years ago by Dickson Despommier, Professor of Public Health at British Columbia University.
Big vertical farms do not yet exist, but could be a reality soon. These “vertical farms” would produce crops, poultry and fish year-round in a controlled environment free of pollutants, parasites and dangerous microbes. Despommier suggests that a 30-storey building with a basal area of 5 acres (2.02 ha) has the potential of producing crop yield equivalent to 2,400 acres (971.2 ha) of traditional horizontal farming.
Advantages of vertical farming / hydroponic cultivation
Despommier is now conceptualising several projects with administrators around the world. He does not quite divulge details but says that administrators from Chicago and New York are interested, and that he is working with people in other countries as well. Companies are also trying their own variations in smaller scales.
The vertical farm is more than just a produce factory. It also offers an alternative to rebuild a city’s infrastructure to mimic natural-resource cycles in the tower’s basement, where sewage provides the farm’s most crucial resources: energy and water. The surrounding city’s sewage system would be redirected to the farm where half of it would enter a “SlurryCarb” machine developed by EnerTech, a green-energy start-up in Atlanta. The device heats and pressurises the sludge, breaking it down into its base components-carbon and water. The machine extracts the water and the solid, coal-like slurry burns to power steam turbines that generate electricity.
The rest of the sewage is treated with bacteria-killing chemicals and turned into topsoil through a heating and drying process developed by N-Viro, an Ohio-based biosolids-recycling company. Water extracted from both processes is filtered through natural “bioremediators” such as zebra mussels, cattails and sawgrass that clean it until it’s suitable for agriculture or further refine it for drinking. Any farming waste is composted to make fertiliser and methane gas, which can utilised for energy production.
The basis of vertical farming is hydroponic (water based and soil-less) culture in nutrient solutions. For hydroponic cultivation, the nutrients consist of five macro elements (required in large quantity) and six micro elements (needed in small quantity). For the fixing of roots, a variety of inert supporting media like sand, gravel, coco coir, vermiculite, perlite, rookwool, and dihydro are used.
Two types of hydroponic systems employed are: passive or open system where nutrients are not recycled and do not use any power or pumps. The drawbacks of such a system are that it requires less care but are used for small plants with little produce and fresh items like salads and other greens. The active or closed systems involve power driven with pumps for the circulation of nutrients solutions through roots. These are more efficient but require more care and are used for large-scale cultivation. The active systems may (ebb and flow, drip irrigation) or may not contain the root supporting media.
Though hydroponics is the technology-based farming method for future, it has been utilised for hundreds of years by a variety of people. As noted in “Hydroponic Food Production” (fifth edition, Woodbridge Press, 1997, page 23) by Howard M. Resh: The hanging gardens of Babylon, the floating gardens of the Aztecs of Mexico and those of the Chinese are examples of hydroponic culture. Egyptian hieroglyphic records dating back several hundred years B.C. describe the growing of plants in water.
Vegetables are being cultivated successfully in space, South Pole and atomic submarines through vertical farming using hydroponic systems. Anna Heiney of NASA’s John F. Kennedy Space Center says “NASA has extensive hydroponics research plans in place, which will benefit current space exploration as well as future, long-term colonisation of the Mars or the moon. As we haven’t yet found soil that can support life in space, and the logistics of transporting soil via the space shuttles seems impractical, hydroponics could be the key to food for astronauts thousands of miles from earth”. They could grow crops that would not only supplement a healthy diet but also remove toxic carbon dioxide from the air inside their spacecraft and create life-sustaining oxygen. “If you continually re-supply and deliver commodities like food that will become much more costly than producing your own food,” says Ray Wheeler, Plant Physiologist at Kennedy Space Center’s Space Life Sciences Lab.
In fact, hydroponics was chosen as the food production technology at the South Pole but the 1978 Antarctic Conservation Act prohibits the importation of soils to the continent. However, with so much fresh water available in the form of ice, the soil-less culture of hydroponics could be a perfect fit. The McMurdo food growth chamber provides the 200-plus station personnel with fresh salads and veggies like cantaloupes, pepper, broccoli, tomatoes, cucumber, besides a bright, green environment that is missed during the dark months when working through the Antarctic winter.
First, hydroponics offer people the ability to grow food in places where traditional agriculture simply isn’t possible. In areas with arid climates like Arizona and Israel, hydroponics has been in use for decades. This technique allows people to enjoy locally grown produce and enhance their food production.
Similarly, hydroponics is useful in dense urban areas. In Tokyo, hydroponics is used in lieu of traditional soil-based agriculture. Rice is harvested in underground vaults without the use of soil. Because the environment is perfectly controlled, four cycles of harvest can be performed annually instead of the traditional single harvest.
Hydroponics is also useful in remote locales such as Bermuda. With so little space available for planting, Bermudians have turned to hydroponic systems which take around 20 per cent of the land usually required for crop growth. This allows the citizens of the island to enjoy year-round local produce without the expense and delay of importation.
Finally, areas that don’t receive consistent sunlight or warm weather can benefit from hydroponics. Places like Alaska and Russia where growing seasons are shorter use hydroponic greenhouses with controlled conditions.
Interestingly, after a strawberry farm in Florida was wiped out by hurricane Andrew, the owners built a hydroponic farm. By growing strawberries indoors and stacking layers on top of each other, they now produce on one acre of land what used to require 30 acres. In the US, hydroponic tomatoes yield 150 tonnes per acre annually, which is 18 times of what is produced through conventional soil methods. A 10-acre site can yield 3 million pounds annually. In Canada, the average per capita consumption of tomatoes is 20 lbs. Thus, with a population of 20 million, the total annual consumption of tomatoes is 400 million pounds (200, 000 tonnes). Enough tomatoes for the entire population of Canada for a whole year could be grown hydroponically on just 1,300 acres of land!
|Vertical Farm Technologies||NY, US|
|Valcents||BC,Canada (Multilocational projects)|
|AeroFarms™||UAE and Middle East|
|Terrasphere- taken over by Converted Organics)||Boston US|
|Shimizu Corporation (Wall farming)||Japan|
|Sadler Machine Co||Design for South pole|
|Weber Thompson Design||Seattle|
The Institute of Simplified Hydroponics (ISH), USA, along with the Institute of Simplified Hydroponics, India, launched the “Pet Bharo – Hydroponics for sustainability” project in Bangalore and the “Women of Hope Project” in Hyderabad in January, 2009. These projects were launched to empower the people of India by making available low-cost, easy-to-learn hydroponics or soil-less production. The major goal of the ISH is to remove hunger and malnutrition and generate some income for the poor and less privileged families.
This writer has some experience in growing “hydroponic tomato” and does not find growing vegetables in soil-less culture using nutrient solutions very expensive. Indeed, this type of simple farming would be a boon to entrepreneurs in the remote and snow-bound areas of the North-East, Jammu and Kashmir and Himachal Pradesh which remain cut off from the rest of the country during winter months. People in these areas, while confined to their four walls due to adverse climatic conditions, can produce fresh vegetables and salads. The defence forces, too, can make use of this technology for their personnel in inaccessible areas during the inclement weather.
This article was published in Opposite Editorial Agriculture in “The Tribune” on 12th Feb 2011.