Now we move on to artificial lighting for plants.
Christopher Benak, president and co-founder of ALD Green, had one brand-new model front and center.
“We bioengineered a light that is specifically designed for flowering plants, whether it’s tomatoes, peppers, cannabis,” said Benak. “We put on smart controls so that you can wake plants up with their circadian rhythms and put them to sleep similar to a day.
Just like humans get up with the sunrise and have the sunset to signal oncoming night, plants have their own circadian rhythms.
Rather than blasting sunlight at noon during the day, Benak said, the LEDs wake it up slowly and put it to sleep slowly during the day.
Year after year, cities expand and pristine natural habitats are turned into farms and pastures to support the world’s growing population. But despite our encroachment into the environment, we still struggle to feed everyone. Vertical farms could offer a solution by producing higher crop yields year-round in less space than conventional agriculture.
What Is Vertical Farming?
With land for crops and pastures growing scarce — plus the threat of pesticides and herbicides taking a toll on our health and the environment — people are exploring new ways to grow food, such as urban agriculture. In general, this is the process of growing food within city limits – whether on rooftops, in backyards or on balconies. The goal is to provide families with fresh, healthy food that isn’t laced with chemicals — and when you grow your own crops, you can control these elements.
Vertical farming is a type of urban agriculture – but vertical farms are often constructed indoors in extremely controlled environments. Crops are grown on shelves that extend upward instead of outward, and the environment is carefully monitored, so crops grow year-round.
In addition to growing crops, some vertical farmers have developed ways to grow fish in a self-sustaining system. Water from the plants is recycled into fish tanks, and the waste from the fish becomes fertilizer for the plants. Then, both the plants and fish can be harvested for food.
The benefits of vertical farming
The benefits of vertical farming are numerous. Farmers can control the crops’ environment in vertical farms, so the plants aren’t subjected to nasty weather conditions or droughts. Humidity, nutrients and water are administered to growing plants to achieve optimum growing conditions. Because of the controlled environment, crops can be harvested more than once a year, resulting in higher yields than traditional farming.
Vertical farms are more sustainable than conventional farms because they use less water (which is often recycled through the system), they take up less space and they use less fossil fuels because they don’t rely on heavy machinery such as tractors and harvesters.
Technology helps vertical farmers get the best output from the farm. Tailored lamps help plants get more light exposure, which encourages them to grow faster than crops that rely on the sun. Vertical farms also provide greater protection from insects, thus
decreasing the need for harmful chemical products.
Downsides to vertical farming
While vertical farms can help with local hunger issues and sustainability, there are some barriers that may keep them from gaining worldwide traction. The cost of setting up a vertical farm can be prohibitive. Conservative estimates put the initial start-up cost at around $110,000, but there are estimates upward of millions of dollars.
Finding an abandoned warehouse or building in an urban setting for a reasonable price might be difficult. Since vertical farms rely on electricity for growing lamps and strict environmental controls, the location has to have reliable power — not just any old abandoned building will do. Vertical farms also depend heavily on technology, which can be costly. Keeping the lights on and the environmental controls running will impact energy use — and your budget.
Not every crop that is grown traditionally can be raised successfully in a vertical farm. Leafy greens and herbs do the best in an indoor environment, while staple crops like wheat and potatoes are difficult to grow indoors, as are some fruits and vegetables. The crops that can be harvested from a vertical garden are limited.
Growing food to feed the hungry is a noble gesture, but it also has to be profitable, especially when the initial cost to set up a vertical farm is so high. If there isn’t a market in your area, it’s a waste of time to grow large amounts of food that you won’t be able to sell.
Despite the downsides, the positives are plentiful. In addition to embracing sustainability and helping combat hunger, vertical farms can also encourage support for local economies. These farms can create jobs, turn a profit and provide a healthy source of food for locals.
As technology continues to advance, new approaches will improve the efficiency and productivity of vertical farms. If nothing else, the idea sparks the conversation about changing the agricultural industry and gives us a place to start for finding better, more sustainable ways to grow food.
Light-emitting diodes (LEDs) have the potential to replace high-pressure sodium (HPS) lamps as the main delivery method of supplemental lighting (SL) in greenhouses. However, few studies have compared growth under the different lamp types. We grew seedlings of geranium (Pelargonium ×hortorum), pepper (Capsicum annuum), petunia (Petunia ×hybrida), snapdragon (Antirrhinum majus), and tomato (Solanum lycopersicum) at 20 °C under six lighting treatments: five that delivered a photosynthetic photon flux density (PPFD) of 90 μmol·m−2·s−1 from HPS lamps (HPS90) or LEDs [four treatments composed of blue (B, 400–500 nm), red (R, 600–700 nm), or white LEDs] and one that delivered 10 μmol·m−2·s−1 from HPS lamps (HPS10), which served as a control with matching photoperiod. Lamps operated for 16 h·d−1 for 14 to 40 days, depending on cultivar and season. The LED treatments defined by their percentages of B, green (G, 500–600 nm), and R light were B10R90, B20R80, B10G5R85, and B15G5R80, whereas the HPS treatments emitted B6G61R33. Seedlings of each cultivar grown under the 90 μmol·m−2·s−1 SL treatments had similar dry shoot weights and all except pepper had a similar plant height, leaf area, and leaf number. After transplant to a common environment, geranium ‘Ringo Deep Scarlet’ and petunia ‘Single Dreams White’ grown under HPS90 flowered 3 days earlier than those grown under HPS10, but flowering time was not different from that in LED treatments. There were no consistent differences in morphology or subsequent flowering among seedlings grown under HPS90 and LED SL treatments. The inclusion of white light in the LED treatments played an insignificant role in growth and development when applied as SL with the background ambient light. The LED fixtures in this study consumed substantially less electricity than the HPS lamps while providing the same PPFD, and seedlings produced were of similar quality, making LEDs a suitable technology option for greenhouse SL delivery.
The use of light-emitting diodes (LEDs) to support plant growth is a radical departure from use of gas-discharge lamps, which were developed in mid-19th and widely adopted by the industry during the 20th century. Initial investigation by the National Aeronautics and Space Administration (NASA) in the late 1980s on the use of LEDs to grow plant in space is resulting in an industry-wide transition from gas discharge to solid-state lighting systems. This global transformation is given urgency by national policies to reduce energy consumption and being facilitated by ready access to information on LEDs. The combination of research, government policy, and information technology has resulted in an exponential increase in research into the use and application of LED technology in horticulture. Commercial horticulture has identified the opportunities provided by LEDs to optimize light spectra to promote growth, regulate morphology, increase nutrient content, and reduce operating costs. LED-light technology is enabling the development of innovative lighting systems, and is being incorporated into large-scale plant factories for the production of edible, ornamental, and medicinal plants. An overview of prevalence of readily accessible information on LEDs and implications for future adoption in horticulture is discussed.
International Society for Horticulture Science
|Keywords:||photosynthetic efficiency, blue light, red light, green light, growth analysis, net assimilation rate, leaf area index, crop growth rate|
We have characterized the effects of individual wavelengths of light on single leaf photosynthesis but we do not yet fully understand the effects of multi-wavelength radiation sources on growth and whole-plant net assimilation. Studies with monochromatic light by Hoover, McCree and Inada nearly a half century ago indicated that blue and cyan photons are used less efficiently than orange and red photons. Contrary to these measurements, studies in whole plants have found that photosynthesis often increases with an increasing fraction of blue photons. Plant growth, however, typically decreases as the fraction of blue photons increases above 5 to 10%. The dichotomy of increasing photosynthesis and decreasing growth reflects an oversight of the critical role of radiation capture (light interception) in the growth of whole plants. Photosynthetic efficiency is measured as quantum yield: moles of carbon fixed per mole of photons absorbed. Increasing blue light often inhibits cell division, cell expansion, and thus reduces leaf area. The thicker leaves have higher photosynthetic rates per unit area, but reduced radiation capture. This blue-light-induced reduction in photon capture is usually the primary reason for reduced growth in spite of increased photosynthesis per unit leaf area. This distinction is critical when extrapolating from single leaves to plant communities.
DOE studies SSL for energy savings in horticultural lighting
Editor in Chief, LEDs Magazine
The US Department of Energy said that a complete switch to LED lighting for horticultural applications would deliver 3.6 TWh in energy savings or $240 million annually in the US.
The DOE has recently released a research report that contemplated how much energy could be saved annually were the horticultural industry to make a complete and immediate transition to LED-based SSL. The agency studied SSL deployment in supplemental greenhouse lighting; in ceiling-mounted, single-layer growing operations lit solely by electric light; and in emerging vertical farms where multiple layers of plants are lit with electric light. In aggregate, the report said an LED transition would deliver 40% savings, equating to $240 million per year.
The report “Energy savings potential of SSL in horticultural applications” followed the same formula that the DOE has used in theoretically projecting what an immediate and complete SSL transition could deliver in general lighting. The agency has released a report called “Adoption of LEDs in common lighting applications” at two-year intervals. The 2017 report projected potential savings of $44 billion per year if all lighting in the US were swapped to LEDs.
Clearly, the horticultural opportunity is not that large, although savings of 3.6 TWh per year would take a significant burden off the national power-generation burden. Moreover, population and the need for more food will only escalate.
The DOE said supplemental lighting is presently used in 26.8 million ft2 of greenhouse space. Non-stacked space lit artificially totals 18.7 million ft2. The nascent vertical farms market is only 0.5 million ft2 now but has tremendous potential for growth. According to the DOE, LEDs make up 2% and 4%, respectively, of the first two applications but 66% of the vertical farm application that really wasn’t feasible prior to LEDs (see chart above).
Indeed, as we have reported before, the exciting element to LED lighting used for horticulture comes from the new applications such as vertical farming and with changes to more efficient techniques in other applications. The evidence suggests that LEDs can deliver tunable light recipes that have the potential of increasing yields while saving energy.
ALDgreen has developed LED technology that utilizes advanced, more efficient spectrums paired with leading edge software providing cultivators better plant characteristics and yield.
We just published an article that covered some of the most compelling presentations from our US Horticultural Lighting Conference held in late 2017. And we are planning two such conferences for 2018. The Horticultural Lighting Conference Europe will be held May 14–15 in the Netherlands. The Horticultural Lighting Conference US will be held Oct. 9–10 in Portland, OR. You can follow all our horticultural lighting content at our dedicated microsite on the topic that is a companion to our main website.