8 challenges holding back vertical farming facilities
May 31, 2023
May 31, 2023
Scaling up controlled environment agriculture is a tricky business
A version of this blog appeared as “Ripe for innovation” in Design Quarterly Issue 18.
Vertical farming is poised to gain momentum in the next 10 years, with a nudge from government subsidies, a growing global food demand, climate change concerns, and innovation that makes indoor growing more efficient and profitable.
Traditional methods of cultivation are insufficient to meet rising global demand. There’s a place and time for large-scale vertical farming—sometimes referred to as indoor farming or controlled environment agriculture (CEA)—to really take off, but we’re not there yet.
Many of us have seen vertical farming facilities or products in stores, but these are typically pilot projects, either subsidized or not yet profitable. While Europe is racing ahead on CEA, North America has not been able to make it work for the long term. Small-scale vertical farms, say a shipping container outfitted to grow produce for a village, have been deployed successfully. But scaling up vertical farming is more than a matter of building 200 container farms.
While we’re not there yet, there will be a time when more grow-and-buy-local is necessary for supply chain resiliency and efficient resource use. Inevitably, if weather patterns keep changing and the world’s urban population keeps growing, we will need to expand vertical farming and make it work.
In the US, we get some of our produce, lettuce or avocados for example, from places where the climate is favorable all year. Changing weather patterns, such as extreme drought in California, can affect our food sourcing and supply chain. Although plants can be hearty, we’re still at the mercy of weather patterns when it comes to supply.
Through the pandemic we’ve become aware of our dependency on the global supply chain. Building food supply resiliency means growing more food closer to home. In theory, reducing food miles reduces our energy consumption and emissions related to climate change.
The sun is a free resource, but sun exposure to plants varies seasonally. With vertical farming, we replace the sun with lights and tune them to optimize plant growth at each phase. For example, seedlings and sprouts receive less hours of light to mimic springtime’s shorter days.
Likewise with irrigation. We can ensure the produce we’re growing gets the right amount of light, water, and nutrients (from soil or hydroponics) when required. When we grow indoors, we remove some of nature’s unpredictable variables. We add the reliability of traditional food manufacturing. Vertical farms are more likely to be successful when they achieve the efficiency of a manufacturing operation.
Produce has a shelf life. So, when you grow produce, you need a destination for it. Vertical farming offers a more predictable harvest and a more dependable product stream for the suppliers and buyers. Whereas growing outdoors, a cloudy week during the initial growth phase can disrupt your harvest for weeks. With vertical farming, you can stagger production and make it repeatable. This systematic approach to farming means you can offer the right quantity of lettuce every week.
So, what’s holding vertical farming back?
Let’s look at eight aspects of vertical farming we need to solve to make it a reality.
To grow, we need water, light, and nutrients. To reach a profit margin where a head of lettuce or a bell pepper costs what people expect to pay—not $8—we still have a long way to go. Never mind that it’s organic, free of GMOs, free of pesticides, doesn’t need to be washed, or grown locally. Vertically farmed produce needs to be available at an acceptable price point to catch on.
To make vertical farming profitable, we need to scale up. Growing 5 plants at a time or 500 is not the same as growing 5,000 or 50,000.
A good deal of vertical farming technology already exists. We can size the pumps, we can flow water, we can measure and supply nutrients. But to make vertical farming work at scale, we need a lot of automation. The future of vertical farming is a factory where the technology for seeding, watering, harvesting, getting rid of bad plants, and packaging the good ones for sale runs with little human intervention.
We can use the robotic tech from the traditional food and beverage space. Automated harvesting, say chopping lettuce, already exists. But to harvest indoors and keep our plants living and regrowing, we need more sophisticated technology. We don’t yet have tech that can pick tomatoes from a tomato plant without tearing it apart.
Through the pandemic we’ve become aware of our dependency on the global supply chain. Building food supply resiliency means growing more food closer to home.
Plants are as easy to grow as they are easy to kill. Tending to 10 plants in a container-sized indoor farm is one thing. Tending to 10 different grow rooms with various plants at different growth phases is another.
Even indoors, plants are susceptible to disease. Threats to growing plants are magnified greatly when we keep them in the same confined space. A bad batch of seeds or the wrong nutrient mix can wipe out an entire harvest.
Growing plants indoors requires specialized lighting. Even the latest LEDs consume a large amount of power. To grow indoors, we need moist, humid rooms. But we also need to be able to take that moisture out when needed. Thus, HVAC units are running almost 24/7 in these giant controlled spaces. The very tight temperature tolerances we need to ensure that the plants are ready for harvest drive the cost of these food factories.
The building infrastructure for a vertical farm is not complicated. We can start with the shell of a building, a warehouse space, or a purpose-built industrial building. But all that power must be supplied by the local municipality. The scaled-up vertical farm is going to pull hundreds of megawatts, so finding the right community partner is crucial.
Even if a local government is excited for a large vertical farm, it may not have the power infrastructure in place to support the intense power needs. It may take years for a community to develop the needed power infrastructure.
Traditional outdoor industrial farms collect and use a great deal of rainwater for irrigation. The vertical farm must use “boutique” water. This processed water is pumped full of nutrients to give the plant exactly what it needs in place of what it would draw from the soil. A large-scale vertical farm consumes millions of gallons of water.
Someone must clean up that water and process it so it can be used again. Recovery is sometimes dictated by the municipality. So, the large-scale vertical farm has significant wastewater system needs. It also has options in how it approaches water treatment and reuse. For example, the vertical farm operator might consider using systems to treat its own water, perhaps recouping some nutrients and water in the process. Here there may be opportunities for the vertical farm to achieve efficiencies that benefit the bottom line and make it a welcome neighbor.
To achieve repeatability that’s necessary to create a quality product in this facility and harvest a great bell pepper or purple carrot every time, we need to process engineer the factory for consistent inputs and outputs.
Each plant requires the same nutrients, the same water flow, and the same climatic conditions. Taking a close look at the growing zone, we see some thorny issues. How do we guarantee that the plant closest to the process pump or reservoir is not stealing all those nutrients? How do we make sure that the plant at the very end of your growing tray is getting what it needs? If we can devise affordable engineering solutions for these questions, we will unlock large-scale vertical farming.
System selection can make the difference between a viable business and a money-losing large-scale vertical farm. Will one giant HVAC system suffice, or do you need 10 smaller HVAC systems each assigned to a unique growing zone? Which system best achieves the need to grow plants and the need for efficient operations?
A vertical farm built to operate at scale isn’t exactly flexible. It has highly specialized systems. Consider that HVAC unit, for example, because it is rated for a room with 50,000 plants. If your start-up opens that room with just 20,000 plants, the unit will be off its performance curve. We will need to fine tune rooms for a specific crop. This presents another challenge for launching vertical farming at scale, but there may be innovative, even modular approaches we can engineer that allow for a multistage scaling up.
Say we can build a vertical farm to scale. We need to be profitable to survive. Who is buying and where are they? To make vertical farming work, we must connect it to a robust supply chain, a market that can take on product right away and sell it. Can we get 50,000 plants to 1,000 grocery stores that will sell them before their shelf life comes up? We must sell the produce in a timely manner.
Profit margins are slim. Partnering with farm shares, major retailers, and more are the pathways to building stable, reliable demand. Large-scale vertical farming will need to serve major metro markets to succeed. We will need to build them in proximity to existing produce transport systems.
To launch vertical farming at scale, we’ll first need to engineer solutions for all these issues above. Someday we will grow a great deal of our food indoors. It’s just a matter of how soon.