There is a growing trend in, well, growing: vertical farming. Vertical farming has several distinct advantages over traditional horizontal farming, particularly in areas with limited land, nutrients, water or other resources required to grow plants. In general, vertical farms take up less space and use less water, meaning they can be placed in urban environments. Crops can be grown much closer to their markets, meaning there are lower transportation costs and less environmental impact, according to the USDA.[1]

Source: Lettuce in an indoor, vertical farm. [2]Source: Lettuce in an indoor, vertical farm. [2]

Vertical farming environments

Vertical farming can take place virtually anywhere, due to its much smaller physical footprint. This means growing plants is possible in urban environments, unprofitable mine shafts, shipping containers, rooftops and building lobbies. It is one way to take unused or unprofitable space and turn it into something of value.

These vertical farms take up less physical space, making it more efficient to fertilize, water and place plants under climate and light control than a larger, horizontal farm. For example, an unexpected cold front can ruin tomatoes. Farmers try to prevent this by covering each individual plant (time consuming) or by placing large fans in their fields to enhance atmospheric mixing and keep the ground layer from becoming too cold. It is far too expensive to try to grow blueberries or tomatoes in a large warehouse and control the climate. Instead, vertical farming could be used to grow tomatoes year round. Because there is less space to heat, and less heat is lost to the surrounding environment, the tomatoes can live in favorable conditions and be much more profitable.

While the United States has an abundance of fertile land for farming, some countries do not have such a luxury. Hong Kong, with its large urban areas, imports 90% of its food, much of which comes from mainland China.[3] Other countries, such as the United Arab Emirates, have poor soil quality, and import much of their food as well.

Environmental impact of vertical farming

Currently, much of the fresh fruit, vegetables and herbs that are produced in the United States are grown in rural areas. The produce must be shipped to urban and suburban areas for sale and consumption, incurring environmental impacts in terms of vehicular emissions. Furthermore, the time spent in shipping means that a significant portion of the produce spoils in transit, and is neither sold nor eaten, representing a financial and energy loss.

Enter vertical farming. Instead of needing a vast expanse of farm land, grocery stores could supplement their produce department with a vertical rooftop garden, reducing the detrimental impacts of transportation. Furthermore, any produce that did spoil could be composted and used to fertilize new crops instead of being tossed in the garbage.

Vertical farming is not limited to food. Suppose a wildfire has left a ruined burn scar in a forest. A few intermodal containers with native grasses and seedlings are delivered to the area and tended to by foresters, then planted in the burn scar to stabilize the soil faster than it could have naturally recovered. With vertical farming inside the containers, the foresters could keep a rotating stock, planting seeds in the intermodal containers, then planting the grasses and seedlings as they grow until the area has recovered.

Food security

Another positive impact of vertical farming is the ability to grow crops of all varieties in virtually all climates. Instead of having to ship rice from Southeast Asia to the Middle East, or corn and wheat from the American heartland to Japan, products can be grown in otherwise inhospitable environments. Using vertical farming and hydroponic techniques, water can be cycled in a way to water only the plant rather than wasting it on dry soil, as often happens in horizontal farming. This can lead to rice production in arid climates, making entire swaths of the planet more inhabitable. It also provides people with a varied, potentially more nutritious diet, regardless of where they live.

Vertical farming, particularly indoor farming, has the potential to limit the spread of fungi, disease and pest impacts on crops. The indoor aspect of vertical farming could be carried out in a way to isolate diseased crops and prevent them from spreading to other areas. In horizontal farming, a diseased field may need to be burned quickly -- if not, the disease, fungus or pest could spread to another field, or be carried on the breeze to another farm entirely.

“Wheat Rust” could be detected early and stopped before spreading to other plants with indoor, vertical farming techniques.[4]“Wheat Rust” could be detected early and stopped before spreading to other plants with indoor, vertical farming techniques.[4]

Limitations

While vertical farming is useful for delivering fresh produce to market, it may prove to be more difficult to grow enough food for some of the products that are regularly consumed. Some products are derived from fresh produce, but then treated to become ingredients in other food, such as starches, oils, thickening agents, coloring agents, flavor enhancers and so on.

The author of this article once toured a “small” corn processing plant in Illinois which produced corn oil, high fructose corn syrup and xanthan gum. While high fructose corn syrup is falling out of favor with some health experts, it is still in high demand. Xanthan gum and corn oil are used as ingredients in many prepackaged products as well. This “small” operation processed the equivalent of 28 acres of corn per day!

Another limitation is the fact that horizontal, traditional farming is efficient and inexpensive. Vegetables are inexpensive; in the desert climate of Albuquerque, even water-intensive crops such as cucumbers, watermelon and rice are readily available and very inexpensive. A bag of frozen broccoli, with all of its growing, transportation, cooling and store overhead can be purchased for under a dollar. On the east coast, there is a saying, “don’t leave your car unlocked, or someone will put zucchini in it”, because it grows so readily that gardeners can hardly give it away before it spoils.

Upcoming challenges and opportunities

Humans have been farming horizontally for many years. Because of this, most of the tooling, equipment and techniques for farming have been developed for horizontal farming. Packets of seeds often specify how many feet of horizontal row are contained in the packet. Tractors, harvesters and most mechanized farming equipment are designed to traverse horizontal rows, planting and harvesting crops quickly.

In contrast, vertical farming requires more manual labor, as the tooling for vertical farming is still in its infancy. As market demand for vertical farming tools increases, so will innovation, driving down the labor and costs. As the tools are developed and the labor load decreases, so will the amount of vertical farming.

As Earth’s population continues to grow, civilization will continue to push farther into the remote areas of the planet. Suburbs will be absorbed into the city, and rural communities will become the suburbs. The limited acreage of fertile farmland will continue to decrease, and the need for new farming techniques will become vital to the continuation of life on Earth. Vertical farming will likely play a role in the future of food security for mankind.

[1] Fedderman, Sarah. Vertical Farming for the Future. https://www.usda.gov/media/blog/2018/08/14/vertical-farming-future, published 8/14/18, accessed 3/17/21.

[2] https://en.wikipedia.org/wiki/Vertical_farming#/media/File:VertiCrop.jpg, accessed 3/15/21.

[3] Southey, Flora. Are Verical Farms Even Remotely Efficient? Putting a Figure on Plant Factories. https://www.foodnavigator.com/Article/2019/05/15/Are-vertical-farms-even-remotely-efficient-Putting-a-figure-on-plant-factories Published 5/15/19, accessed 3/17/21.

[4] https://commons.wikimedia.org/wiki/File:CSIRO_ScienceImage_10772_Rustaffected_wheat_seedlings.jpg, accessed 3/17/21

To contact the author of this article, email engineering360editors@globalspec.com