1. Definition:
Vertical farms are multistorey多层的 buildings used for growing crops or rearing animals. The basic idea is to produce food without soil in specially constructed skyscrapers.
Vertical farming takes the idea of indoor farming, control of environmental factors, by cultivating agricultural products in skyscrapers, claims to solve the food crisis and offer a green solution to farming

2. Examples: * Commercial-scale vertical farm in Singapore:
In 2012, the first commercial-scale vertical farm has opened in the tiny, densely populated city of Singapore, with the aim of decreasing dependence on food imports. The vertical farm, which has been developed by Sky Green Farms, consists of 120 aluminum towers, each extending up almost 30 feet in height. It can produce over 1,000 pounds of three kinds of vegetables per day, all of which are sold in the local FairPrice Finest supermarkets. However, they do cost a little more than imported vegetables.

* Vertical farming in Chicago:
The largest scale vertical farm project probably closest to realization is Chicago’s The Plant, a collaboration of the Chicago Sustainable Manufacturing Center and the Illinois Institute of Technology, a vertical farm that would occupy a former meatpacking plant in Chicago’s Back of the Yards neighborhood. The Plant is to try to create a zero-net-waste ecosystem including mushroom and vegetable gardens and a fish farm.

* Zoo farm :
The 100 square meter farm at Paignton Zoo grows leaf vegetables for animal feed. It applies a technique called hydroponics, where plants are grown in nutrient rich solutions instead of soil. Stacked in trays eight layers high, the crops are continually rotated to ensure that all have adequate access to air and sunlight. The system also allows nutrients that have not been directly taken up by the plants to be collected and recirculated, along with the water, reducing usage and minimizing waste.

A proposed $200 million sky farm in the city of Las Vegas would be the world's first 30-story vertical farm. This building would have 30 floors of indoor farm land, and it is estimated that a vertical farm such as this one could produce enough food to feed 72,000 people per year.

A new vertical farm in the downtown area of Toronto, called SkyFarm, could help to feed 35,000 area residents each year. This proposed SkyFarm would only require about 1.32 hectares of land for the 58 story building to sit on, but bring in the same amount of product as a 420 hectare farm

By the year 2050, nearly 80% of the earth's population will reside in urban centers. Applying the most conservative estimates to current demographic trends, the human population will increase by about 3 billion people during the interim. An estimated 109 hectares of new land (about 20% more land than is represented by the country of Brazil) will be needed to grow enough food to feed them, if traditional farming practices continue as they are practiced today. At present, throughout the world, over 80% of the land that is suitable for raising crops is in use (sources: FAO and NASA). Historically, some 15% of that has been laid waste by poor management practices. What can be done to avoid this impending disaster? 3. Advantages: * Not constrained by seasons: Vertical farming will free farmers from the constraints of the seasons. Any crop will be able to be grown anytime and anywhere. In addition, vertical farmers will also not have to pray for rain or sunshine, nor will they live in fear of hurricanes, floods or droughts.

* No need of pesticides and traditional fertilizers: By adopting technologies and techniques developed for microchip fabrication plants, vertical farms will be built to keep out weeds, insects and diseases. Within such secure, totally controlled environments, pesticides and traditional fertilizers will therefore not be required.

* Less water required: The amount of water required by vertical farms will also be far lower than in the traditional farming because it relies on either hydroponics溶液培养学that results in around 70% savings or aeroponics空气种植法 that reduces water usage by up to 95%. At the same time cycling use of water.

* Will not create agricultural runoff: another major benefit of vertical farms is that they will not create agricultural runoff. Current irrigation systems cause excess water to drain off 逐渐枯竭 the land, with the population from a mixture of silt, fertilizers and pesticides.
Poor land * Transport-resource saving and deducing climate change: vertical farms grow food in cities, it will result in significant oil and other transport-resource savings, so also helping to reduce climate change. If vertical farming in urban centers becomes the norm, then one anticipated long-term benefit would be the gradual repair of many of the world’s damaged ecosystems through the systematic abandonment of farmland. In temperate and tropical zones, the re-growth of hardwood forests could play a significant role in carbon sequestration and may help reverse current trends in global climate change. * Other benefits of vertical farming include the creation of a sustainable urban environment that encourages good health for all who choose to live there; new employment opportunities, fewer abandoned lots and buildings, cleaner air, safe use of municipal liquid waste, and an abundant supply of safe drinking water.


 * * Improved food safety: the food can be consumed within moments after harvesting, which is fresher. Also the nonuse of pesticides and fertilizer let the products more healthy and safety for humans. * Purify water: via the natural process of transpiration, plants will remove the nutrients from human and other waste, so purifying the water.

* Ecosystem restoration: the rise of human civilization has been at the expense of our wider environment. Biodiversity continues to be threatened by human action, and more species become extinct every year. However, if vertical farming causes a sufficient enough volume of future agriculture to move into the city, then a potential does exist for ecosystem restoration.

If we could engineer this approach to food production, then no crops would ever fail due to severe weather events (floods, droughts, hurricanes, etc.). Produce would be available to city dwellers without the need to transport it thousands of miles from rural farms to city markets. Spoilage would be greatly reduced, since crops would be sold and consumed within moments after harvesting. If vertical farming in urban centers becomes the norm, then one anticipated long-term benefit would be the gradual repair of many of the world’s damaged ecosystems through the systematic abandonment of farmland. In temperate and tropical zones, the re-growth of hardwood forests could play a significant role in carbon sequestration and may help reverse current trends in global climate change. Other benefits of vertical farming include the creation of a sustainable urban environment that encourages good health for all who choose to live there; new employment opportunities, fewer abandoned lots and buildings, cleaner air, safe use of municipal liquid waste, and an abundant supply of safe drinking water.




4. Disadvantages: * High cost: One of the main Vertical Farming disadvantage is the high cost associated with this idea. The start- up cost including urban land purchasing cost that is higher than cost of farmland. The extra cost of lighting, heating, and powering the vertical farm may offset any of the cost benefits received by the decrease in transportation expenses.

* More resources: Although this technique is capable of producing higher yields, the maintenance is also much higher. A hydroponic system will require frequent replenishment for nutrients, along with continual flushing to remove fowl water. Farmers will require far more resources compared to traditional farming techniques

* Limited varieties of vegetables and Fruits: Another thing that makes this idea unattractive for the farmer is the fact that they are unable to grow the different varieties of fruits and vegetables in this vertical farm. The reason is that there are only a few varieties of vegetables and fruits that can be produced well in this controlled environment of farm. * More energy use: During the growing season, the sun shines on a vertical surface is much less than when they are planted on flat land. Therefore, supplemental light would be required in order to obtain economically viable yields. As "The Vertical Farm" proposes a controlled environment, heating and cooling costs will be at least as costly as any other tower. But there also remains the issue of complicated, if not more expensive, plumbing and elevator systems to distribute food and water throughout