Vertical Farming: Which System is Best?

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In our last blog, we showed how conventional agriculture is not a solution for food security and sustainability moving forward. Between the need to clear land for increased production, it’s pollution and waste of water, its distance from large cities, and its greenhouse gas emissions, there are a lot of problems that need addressing. In our first blog, we explained the basics of a vertical farming system built around circularity, something we’re researching at Urban Stalk. Here, we want to go a little more in depth.

There are several methods of “water culture”, or farming in a soilless water medium,  that could be potential solutions to the impending food security problem. The three main types of indoor vertical farming systems being researched now are aeroponic, aquaponic, and hydroponic systems.

All of these have some things in common when compared to conventional agriculture: they reduce the amount of space needed, and thus increase your crop output per area; they use much less water, because of closed systems that recycle water instead of the waste and drainage from irrigation; and they are able to be scaled up in urban communities, making for localized growing. These systems are also all built on a foundation of technology that allows complete control at every step of a plant’s life, increasing yield efficiency. But what are the differences between these systems? And which one is the most promising for solving the world’s looming hunger problems?

To learn about each method, keep reading!

Aeroponics

Aeroponics is a developing technology that farms plants without the use of any growing medium. Conventional farming uses soil as a medium and hydroponics uses a water solution, but aeroponics, as its name using “aer” (the Latin for “air”) implies, has the roots of plants sitting in an empty space of air. The root chamber needs to be kept dark, and nutrients are delivered to the plants by spraying a mist of nutrient rich water on the roots.

Aeroponic systems have several advantages over other closed vertical systems. Because there is no need for tanks of large quantities of water, aeroponics lets you save on space and on water. The increased aeration of the nutrient solutions has also been shown to stimulate plant growth and limit disease in the plants, two important benefits.

But aeroponics isn’t a perfect solution. On a commercial scale, your spray nozzles operate at a high pressure, which means you need the energy and space to power accumulator tanks and compressed air. The nozzles that spray the roots are also prone to clogging and require consistent maintenance; without looking after these properly, the nutrients you need to grow the plants are never supplied. They’re also expensive systems for large scale production, because they require technology like constant high-pressure pumps, atomization nozzles, and computers to automatically run the nutrient delivery system. As a last downside, currently the variety of produce that can be grown using aeroponics is smaller than the other water culture options.

Aquaponics

Imagine a farming system where you grow plants at the same time and in the same facility as animals. That’s aquaponics. A combination of hydroponics (growing plants in water-nutrient solutions) and aquaculture (the farming of fish), this system lets you grow vegetables together with fish, in the same building. This ability to have animal protein and nutritious vegetables coming from the same place could be a great advantage for aquaponics.

Here’s how it works.

While typical hydroponics use a precise solution of nutrients to grow the plants, aquaponics put the fish and the plants in an interdependent relationship. Though the plants are held in separate water beds than the fish, the water is recycled in a loop through the whole system. This means that all fish wastewater, with their feces and urine, is reused as nutrient water to grow the plants. The plants filter the waste out of the water, which is then safe to be pumped back into the fish tanks.

There are different types of aquaponic systems, but they all share similar advantages and disadvantages. The benefits of these systems are a smaller need for unnatural fertilizers, the possibility for quicker plant growth, and their self-sufficiency. However, these systems may not be so practical to establish in developing nations. The energy costs to create a habitable environment for both plants and fish, especially in warmer climates, will be quite high, and if these nations don’t have sustainable energy sources, emissions will still be significant. Furthermore, as the technology currently stands, there is always a trade-off between the different needs of plants and fish, which means systems are never totally optimized for the growth of either food source.

Hydroponics

The final vertical farming solution, and the one that we have been researching, is hydroponics, probably the most well-known of the three options. The basics of hydroponics are simple; you grow your plants in a growing tray with the roots hanging in a nutrient rich water solution. There are no animals involved and there are no misting and pressure components to worry about.

This achieves several important benefits. First, a hydroponics system is easier and cheaper to set up than the other alternatives. When you’re trying to implement these solutions on a global scale, especially in developing nations, this is an essential advantage. Also compared to the other two options, hydroponics is relatively low maintenance. You never have to worry about the health of living fish in your system, and there are no misting nozzles to be cleaned one-by-one. Add to this the fact that you can grow more types of produce, with specific nutrient solutions optimized for each variety, and you can see why this is a great option.

Still, it’s not all perfect yet. Hydroponic systems are currently being worked on to make them better suited to grow all types of produce, cheaper for set-up and energy use in developing nations, and more scalable for the quantity of food production we will need in the future. At Urban Stalk, we’re proud to be on the forefront of this research, as we look to make industrial hydroponic farming systems a feasible technology in at-risk communities. Visit Urban Stalk to learn more about our research, hydroponic grown produce, and community initiatives to make locally grown foods a reality.

 

For more information on this topic, visit urbanstalk.ca.

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