Bench Talk

Proponents of vertical farming paint a seductive picture: Fresh food without pesticides, increased production, reduced water consumption, use of vacant inner-city real estate, and more. Making this vision a reality requires precise control of light, temperature, water, and nutrients, and involves a wide range of IoT technologies, including sensors, robotics, and data analysis.

Vertical Farm Technology

Contrary to the pastoral vision of golden fields of wheat swaying gently in the breeze, the vertical farm is closer to a factory than a farm (Figure 1). The technology is changing quickly: Commercial vertical farms are capital-intensive, require millions of dollars of investment to get started, and there is stiff competition from greenhouses and other indoor farming operations.

Figure 1: A vertical farm uses technology in a factory-like setting to ensure products of consistent quality. (Source: Mirai)

Vertical farms use technology at every part of the farming process, ranging from nursery operations to harvesting, as Figure 2 shows:

Figure 2: Technology can help improve every stage of the indoor farming process. (Source: Newbean Capital/Local Roots)

Large indoor growers use a wide range of automated devices, from automatic seeders to nursery robots that reposition pots. Since indoor agriculture is still a small market, few purpose-built pieces of equipment exist, so vertical farmers often adapt technologies from other industries.

Climate Control

Heating, ventilation, and air conditioning (HVAC) systems can help create the optimal growing environment by controlling temperature, humidity, carbon dioxide (CO₂) levels, air movement, and filtration. Plants grow quicker at higher CO₂ levels than the atmosphere’s 400 parts per million (ppm): Tanks of CO₂ increase CO₂ levels in the vertical farm to around 1000 ppm.

Climate control systems run the gamut, from basic fans and heaters through to multi-functional control systems that incorporate the latest chiller, infrared, and UV sterilization technologies. The optimal system for any farm depends on several factors: Local regulations, farm size, type and locations, crop types, and, of course, budget. In selecting a system, there’s often a tradeoff between capital expenditure (CapEx) and operational expenditure (OpEx): More expensive systems tend to be more efficient and have lower operating costs.

Lighting

Compared to the traditional farm that gets free energy from the sun, the vertical farm uses artificial light to promote faster growth, and the cost of energy is one of the largest line items on the budget.

Many vertical farms have traditionally used fluorescent lights; these are relatively cheap to buy, but LED lights, with their greater efficiency, consume about 60 percent less power for the same output. LEDs have technical advantages, too: Their light levels can be precisely controlled, and because they don’t emit much IR radiation (heat), they can be placed close to the plants for best light absorption. LEDs can also create the best combination of light spectrum and intensity that gives the most energy-efficient photosynthesis for each plant species.

Mirai in Japan, for example, uses 17,500 LED bulbs that provide the exact wavelengths that various crops need to thrive. According to the company, the new system has reduced power consumption by 40 percent and increased yields by 50 percent.

Longer term, researchers expect that organic LEDs (OLEDs), which use a film of organic compounds to generate light, will eventually become a more economical and efficient option.

Monitoring and Control

The vertical farm is a closed environment, and farmers take strict steps to eliminate pests, pollen, or viruses. The precautions apply to humans, too: Before entering Mirai’s “Green Room,” workers must take hot showers, wash with shampoo and body soap, and change into sterilized work clothes.

Vertical farms don’t use soil as a growing medium to transfer nutrients to plant roots: Instead they use

• Hydroponics, in which plants are grown in a nutrient-rich basin of water, or
• Aeroponics, where crops’ roots are periodically sprayed with a mist containing water and nutrients

For both methods, operators continually monitor all the macro- and micronutrients being supplied to the plants (Figure 3). Unlike a conventional operation, the water that evaporates from the plants into the atmosphere isn’t lost; air conditioners recover up to 98 percent of water in a vertical farm.

Figure 3: Vertical farms control every aspect of the growing process, from the placement of the lights to the nutrients applied to the roots. (Source: Aerofarms)

The result of the tight monitoring and control is that a vertical farm doesn’t use pesticides, herbicides, or fungicides; the harvest can be ready in as little as 18 days, half the time of a conventional farm. Vertically farmed crops can contain considerably more vitamins and minerals than conventional produce: Mirai claims that their lettuce has up to ten times more beta-carotene and twice the vitamin C, calcium and magnesium of a standard product. In addition, no rinsing is needed and up to 95 percent is useful in cooking, compared to the usual 60 percent.

Robots

What is the next stage of vertical farming? Ruthless cost reduction and even less human involvement, so robots and drones are increasingly used. In Kyoto, Japan, SPREAD has just broken ground on its new “Techno Farm,” a 47,000SF, $175 million dollar factory that’s slated to produce 30,000 head of lettuce a day when it’s complete in 2018.

The farm will use robots that resemble “conveyer belts with arms,” according to TechInsider, to plant seeds, water and trim plants, and harvest them. Compared to SPREAD’s existing Kameoka plant factory, the Techno Farm will cut labor costs by 50 percent and energy costs by 30 percent.

Drones will reduce the number of human operators to monitor large areas. Suppliers to the industry are introducing lightweight drones that are suitable for monitoring crop conditions in large-scale indoor farms: Intel®, for example, offers its Aero Drone, an unmanned aerial vehicle (UAV) development platform that includes a wireless controller and the Intel® RealSense™ camera.

In conventional farming, data analytics provides farmers with both current and historical data on their crops. The information comes directly (from instrumented fields and equipment) and indirectly (via satellites and GPS tracking systems). Data metrics include soil quality and moisture, rainfall accumulation, fertilizer and pesticide levels, and crop yields.

State-of-the-art vertical farms view data collection and analysis as a key element in their business model, employing as many data scientists and engineers as they do agronomists and plant biologists. Aerofarms, for example, collects more than 10,000 measurements during a single growing cycle; the company uses this data to boost yields and quality, as well as to drive down costs towards the point that the vertical farm can be competitive with the best conventional methods.

The vertical farm makes extensive use of technology to grow plants in a factory environment. Just as on a traditional production line, workers and managers monitor and control every aspect of the crop to maximize yields and ensure consistent quality. The data gathered helps improve quality in future generations of “products.”

For more information about electronics in vertical farms, visit Mouser’s Shaping Smarter Cities website