This article series is from the Resource Management in Commercial Greenhouse Production Multistate Research Project.

A renewed interest in urban and controlled environment agriculture (CEA) has come with the increased interest in locally and sustainably produced food. Consumers are more and more demanding that their produce be chemical-free, and they want to know where and how it was grown. Clearly, producing crops in urban environments has key benefits such as proximity to market, increased shelf life, and consumer knowledge about production practices. However, there are also major challenges such as the availability of suitable land that is free of hazardous materials, high property values and taxes, permits and regulations, finding skilled labor, and competition from cheaper field-grown products. The advantage of CEA is that most environmental conditions can be carefully controlled, which allows for year-round production and all but guarantees the highest potential yields. Typical growing structures range from high tunnels to greenhouses (Fig. 1), as well as re-purposed buildings (Fig. 2) or shipping containers (Fig. 3) that allow very little or no sunlight to reach the plants.

Depending on the latitude and the particular season, it is likely that electric lighting is needed to either supplement the naturally available sunlight for increased yields, to extend the day length, or to serve as the sole source of light. Since the human eye is not particularly good at assessing differences in light intensity and because humans can typically operate well in relatively low light intensities, we do not appreciate how much photosynthetic light plants need to grow and develop. In fact, plants need a lot more light than the average person would predict. Therefore, plant lighting is a critical component of urban crop production environments.

Types of supplemental lighting systems

Three different types of electric lamps are commonly used in CEA: fluorescent (FL), high-intensity discharge (HID) and light-emitting diodes (LEDs). HID lamps can be further divided into high-pressure sodium (HPS) and metal halide (MH) lamps. The FL and HID lamps come in different sizes and wattages, but once installed they produce light with a fixed color spectrum. On average, FL lamps convert approximately 20 percent of the supplied electric energy into photosynthetically active radiation (PAR; discussed below) that plants use for photosynthesis. They are often used in growth or germination chambers designed for seedling production or tissue culture. The conversion efficiency increases to around 30 percent for HID lamps. The color spectrum of the light produced by MH lamps contains a little more blue than HPS lamps, and they are most often used in garden centers so that plants appear more true to color. HPS lamps have an effective light spectrum to promote flowering of long-day plants and photosynthesis.

Recent technology advances have made high-intensity LED lamps more attractive as photosynthetic lighting sources: They can be designed to produce a specific color spectrum, or they allow for the spectrum to be adjusted based on the needs of the plant. Unlike HID lamps, LED lamps produce little radiant heat, so they can be placed much closer to the plant canopy without damaging leaf tissue (Fig. 4). However, LED lamps still produce (convective) heat that needs to be removed to ensure efficient operation and maximum lifespan. LED lamps specifically designed for plant growth applications have recently surpassed the conversion efficiency of double-ended HPS lamps and are expected to reach even higher conversion efficiencies in the future. Most high-intensity LED lamps for horticultural applications contain red and blue diodes and may contain white diodes to allow humans to see the true color of plants.

Supplemental lighting parameters

PAR refers to the waveband of light (between 400 to 700 nm) that is utilized by plants for photosynthesis. The amount of PAR a plant receives up to a species-specific level will increase photosynthetic rates and ultimately lead to improved growth, quality, and yield. Approximately 45 percent of the energy from the sun falls within the PAR waveband of 400 to 700 nm. Energy outside the PAR region is less photosynthetically active but may influence plant responses such as leaf/flower color (i.e., UV radiation can promote the concentration of anthocyanins), stem elongation (ratio of red:far-red light and blue radiation), flowering, and can also increase plant temperature (infrared radiation).

PAR is quantified in terms of instantaneous light intensity as the photosynthetic photon flux density (PPFD, units of µmol·m^-2·s^-1). Supplemental and sole-source light intensity guidelines vary by crop and by the amount of sunlight available. Generally, 50 to 90 µmol·m^-2·s^-1 of supplemental lighting from HPS lamps or LEDs are delivered to floriculture young plants and microgreens. Vegetables, herbs, and leafy greens are generally provided with higher supplemental lighting intensities of 100 to 200 µmol·m^-2·s^-1. Light intensities for indoor sole-source applications are often double or higher as those crops receive no sunlight.

The term daily light integral (DLI) is used to describe the cumulative amount of PAR that a square meter area receives over a 24-hour period. The unit for DLI is moles of PAR per square meter per day (mol·m^-2·d^-1). The target DLIs to produce acceptable quality floriculture and high-quality young plants is 10 to 12 mol·m^-2·d^-1 (Table 1). For most cut flowers and greenhouse vegetables, the minimum target DLI to produce an acceptable quality crops is 15 mol·m^-2·d-1. For fruiting vegetable crops increased DLI above 15 mol·m^-2·d^-1 will lead to increased crop yield. However, head lettuce is susceptible to the physiological disorder tip burn and becomes unmarketable when light levels exceed approximately 16-17 mol·m^-2·d^-1 (depending on cultivar and airflow).

For greenhouse production, there can be times when sunlight is excessive (e.g., resulting in tip burn in lettuce). For fruiting crops that can utilize higher DLIs, high amounts of sunlight may not be a problem but may make it difficult to control greenhouse temperature. Shading can be deployed all season long as a shading compound (ie., white wash) or a stationary net/screen, but the preferred method is a motorized retractable system that can be deployed automatically by the greenhouse environmental control computer when the light level exceeds a threshold value. Nighttime supplemental lighting of greenhouses can affect neighbors and thus be considered “light pollution” according to municipal code. Black out curtains can be used to mitigate such light pollution.

Lighting systems can be one of the highest capital costs in CEA. Growers are encouraged to work with a reputable horticultural lighting supplier to develop a lighting plan that will meet crop needs. Beyond the upfront cost and the energy efficacy (which determines the electricity cost) it is important to consider fixture shading and cooling, lifespan, warranty, maintenance and uniformity.

Some fixtures (i.e., FL and certain LED lamps) take up a large footprint for the amount of area they light, therefore these fixtures would provide excessive shade in a greenhouse environment and are better suited for sole source lighting applications. The lifespan of fixtures is usually rated based on the number of hours of operation to reach a certain decline in initial light output. For example, an L70 of 25,000 hours means that light output is expected to degrade to 70 percent of the original output after 25,000 hours of use. Depending on the crop and cost of electricity, it may be useful to replace a fixture or bulb even before the L70 is reached. Growers are encouraged to understand the warranty terms. Some fixtures are warranted for a given number of years and others based on the number of operating hours. Lighting suppliers can calculate a light map that displays the expected light intensity (PPFD) and uniformity at crop height given a particular layout of fixtures. Because lighting is such an important decision, get quotes from several suppliers and talk to colleagues for recommendations.

Finally, plant responses to light greatly depend on the crop being grown and specific environmental conditions (temperature, relative humidity, carbon dioxide concentration). Therefore, as with other production practices, it is highly recommended to conduct small-scale trials with lighting before considering large changes/investments.

A.J. is a professor and extension specialist at Rutgers University (both@sebs.rutgers.edu), Neil is an associate professor and extension specialist at Cornell University (neil.mattson@cornell.edu) and Roberto is an assistant professor and floriculture/controlled environment specialist at Michigan State University (rglopez@msu.edu). Acknowledgements. Financial support was received from the USDA National Institute of Food and Agriculture, Multistate Research Project NE-1335: Resource Management in Commercial Greenhouse Production.

I still remember a time when the only décor a chef would accouter his plates with was parsley — at least at the restaurants I went to. I hardly gave the little green sprig a second glance as I ate the rest of my meal. But there’s been a revolution over the years, with the little green “decorations” playing a more expansive role in the foods we eat. Recently, I went to a five-course tasting at a local restaurant with a stellar reputation, and my expectations were high.

Having never had this type of meal, I wasn’t sure what to expect. Fortunately, the waiter explained the types of dishes that the chef would be preparing and the order of the plates, so we knew more or less how it would go. As the dishes came out, I noticed that, regardless of whether it was pasta, fish, meat or dessert, there were colorful microgreens, herbs or both accompanying nearly every dish. And we ate every last one; each added a spark of flavor and complemented the other elements on the plate. For their size, they certainly packed quite the punch.

Rob Laing, CEO and founder of Farm.One, is well aware of the culinary power and popularity of these tiny plants. The vertical farm has grown 580 different varieties of rare herbs, edible flowers and microgreens in approximately 1,500 square feet of growing space across two locations in the heart of New York City. Chefs appreciate that they can get fresh herbs, edible flowers and microgreens delivered to their restaurants sometimes mere minutes after being harvested, and have a much wider selection than they would if they relied solely on seasonal items. This month, we’re sharing Farm.One's story.

Also in this issue, we have the second installment of the Urban Agriculture series, which focuses on lighting in vertical farms and greenhouses. Leslie Halleck shares her take on how to clearly communicate your production methods to your customers. If you’re interested in growing lettuce, don’t miss Christopher Currey’s Hydroponic Production Primer this month. We hear from growing media guru Brian Jackson of North Carolina State University in our article on wood fiber, and food safety expert Lisa Lupo on the Produce Safety Rule. We round out our issue with growers’ perspectives on maintaining the cold chain and the latest from The Produce Moms.

kvarga@gie.net | (216) 393-0290

Twitter: @Karen_GIE

Photo courtesy of Farm.One

After launching a successful software company in Japan’s version of Silicon Valley, Australian-born entrepreneur Rob Laing made a 180-degree shift in careers. He enrolled in culinary classes, which got him interested in the myriad of ingredients that are incorporated into different dishes. The entrepreneur in him couldn’t help but wonder about the process by which chefs acquire these ingredients, and how they’re grown.

“I became intrigued with the idea of growing rare, unusual ingredients after finding exciting herbs and flowers at farmers markets around the world and wondering if I could apply the new techniques of vertical farming to growing these kinds of items,” says Laing, CEO and founder of Farm.One, a vertical farm located in Manhattan.

Laing wasn’t aware of anyone else trying to grow some of these rare ingredients in close proximity to their prospective customers, so he founded Farm.One with a “small amount” of his own money. The farm is located inside the Institute of Culinary Education, a culinary school in New York City. He says that Farm.One started with a small prototype facility and has grown step by step.

“We raised a little [money] from friends and family in early 2017, and have just started an equity crowdfunding campaign to accelerate our growth.”

There’s now 1,500 square feet of growing space split between two farms: the culinary school and a second, larger farm in Lower Manhattan’s Tribeca neighborhood, underneath the two Michelin-starred restaurant Atera.

“It’s tiny but we manage the space very precisely with software to get the most out of it,” Laing says. Everything is grown in these relatively small facilities hydroponically with LED lighting.

Growing a profitable business model

Although Laing may not have a horticulture or farming background, he has the business acumen to run a startup. Plus, he has had the experience of watching his parents venture into olive production in Australia, and noted some of their challenges, such as keeping destructive kangaroos away from their trees. He quickly found that indoor farming eliminates any potential problems with large animals.

Farm.One currently employs 12 people, six who are devoted to production, five in management and one delivery person.

Catering to the chefs

Farm.One caters to the demand of popular chefs around the city, including Matthew Hyland, owner and chef of Pizza Loves Emily. And although he has only been working with Laing and Farm.One for a few months, he’s been pleased with the arrangement.

“It’s working great. We’ve got custom basil for our pizzas,” Hyland says. “People really like it because it’s something they’ve never seen before.” The custom basil he is referring to is a variety named Pluto, just one of Farm.One’s 580 varieties of rare herbs, edible flowers and microgreens it currently grows.

“Farm.One represents the future of where farming is going,” Hyland says. “We’re trying to have nicer, local stuff at a pizzeria, which is what most people don’t use. They use a commodity product. Farm.One is trying to grow nicer things that are sustainable. We’re trying to do the right thing.”

From farm to table... in no time!

Farm.One’s produce is grown so close to its customer base that it can deliver it by bicycle or subway, literally minutes after it is harvested. Right now, that customer base consists of upscale restaurants in New York City — popular eateries that employ chefs who simply won’t stand for the ordinary.

“Being close by is a huge benefit. The alternative for chefs is to ship product hundreds or thousands of miles, with loads of packaging and delays,” Laing says. “Being able to visit the farm with the chefs’ sous-chefs and line cooks is an added bonus — many young cooks have never seen something growing!”

Farm.One is eager to meet the demands of these chefs and can usually find the plants they are looking for from the 60-plus different international seed vendors that they work with.

“Every time we meet a chef we ask for their dream crop and set out to find the seeds to grow them,” Laing says.

The demand from chefs varies over time, Laing says, but right now the top three items are Pluto basil, a dwarf variety with a powerful cinnamon and clove scent; ‘Miz America’ mizuna, a dark burgundy-colored microgreen with a gentle mustard flavor; and various types of oxalis flowers, including ‘Irish Mist.’ Hyland also likes wasabi arugula, which he uses to spice up his pizzas.

“Chefs love the taste. Without that, we wouldn’t have any customers, so that’s first and foremost,” Laing says. “But they also love being able to specify an exact leaf size, which requires careful growing recipes and exact scheduling.”

Farm.One delivers

Having a party? Farm.One has taken their product on the road. The company delivers an “edible bar” of select herbs and flowers to gatherings around town.

“The edible bar is where we bring the farm to you,” Laing says. “We have a selection of dozens of live plants in a simple hydroponic tray that we can serve to party-goers straight off the stem.” He says the idea actually came from a customer who wanted something special for a corporate event. It was such a hit they’re continuing to offer it to customers.

“People love tasting plants they have never seen or heard of before,” Laing says. “We can provide a general selection, or offer a tailored menu of herbs and flowers that complement specific flavor notes in a product.” For example, they produced an edible bar for Macallan (a whiskey distillery) that matched a new whiskey, which he said was “an exciting and dramatic way of emphasizing the flavor profile.”

Neil is a horticulturist and freelance copywriter for the green industry, assisting businesses with advertising copy, white papers, blog posts, articles, and other digital content. greenindustrywriter.com

Photo: Adobe Stock

No one likes being lied to. When it comes to food and how it’s being grown and produced, consumers have developed a healthy sense of skepticism when it comes to claims of “green-ness.” Greenwashing backlash can be swift and consumer expectations are high. But, when you are doing something good, something that’s right, it’s worth every penny to get that message out to your customers.

You’ve seen them as you do your own grocery shopping — the abundance of labels and packaging advertising different foods as “natural” or “sustainable,” products that claim they are good for you, the earth, or are in some way environmentally friendly. Despite the onslaught of such marketing claims — some true, many not — the demand for organic and natural foods continues to rise. There is still plenty of opportunity to make the most of marketing your authentic sustainable practices.

Local rules

Where your produce is grown makes a huge difference to shoppers. As consumers shop more at local farmers markets, they’ve become attuned to the distance the produce traveled before they buy it. Locally grown produce is in high demand. Now, the term “local” means different things to different people, but if you go by typical farmer’s market standards, food grown within 200 miles of point of sale qualifies. Some markets limit produce sales to within a 50-mile radius. Closer is always better.

If you have a retail customer network that is within a tight radius from your production facility, this message should be one of your topmost marketing priorities. If you package your produce, consider creating special packaging for produce that will be sold within a close radius, to highlight its local origin. If you aren’t packaging or labeling your produce, be sure you’re working with retailers (or with their in-house marketing team) to provide them with good in-store signage that clearly communicates your growing location.

Don’t rule out D2C (direct-to-consumer) marketing. (Editor’s note: Read Leslie’s column on direct-to-consumer marketing here) While your customer might be the retailer, the end consumer needs to understand what makes your produce the better choice. You can’t always rely on your retailers to do your marketing for you. D2C marketing can be a great choice for marketing locally grown produce.

Organic

The word on the street is that we need more organic produce, and supply is not meeting demand. Food grown chemical-free may not be important to all consumers, but it is very important to a growing customer segment. Even consumers who ride the fence on organics may prioritize buying certain types of produce that are grown organically or naturally, while still accepting other foods that aren’t. Often these middle-of-the-road consumers are health conscious; but they are choosing some produce based on price alone when they can’t discern special differences. They need more specific information to influence their purchasing decision.

To get the right customer’s attention, you need to make it obvious very quickly that your produce is grown organically or with sustainable growing methods. Get specific about your growing practices and make it clear what you do and don’t use on your crops. This information should be shared on your website of course, as well as your packaging (if you use it), labels, and in-store signage.

If you’re a hydroponic or aeroponic produce grower in the USDA Certified Organic program, you can continue to use the logo. That stamp is meant as a marketing tool to help you make money from your investment in organic growing practices and it has been successful in helping the organic produce market grow.

Maximize the label

As shoppers are better able to navigate traditional advertising slogans and greenwashing, they are turning to a closer inspection of your product label. Now, I realize that if you have labeled or packaged whole produce, there may only be one ingredient. But that doesn’t mean you can’t use the label as an opportunity to describe how the produce was grown, and highlight materials used, or not used, in its production.

Are you using water-saving and water-recycling techniques to grow your crops? Are your practices pollinator friendly? Are you using CHP (combined heat and power) energy management strategies in your greenhouses? Solar power? Do you restrict usage of specific high-profile chemicals — or all synthetic chemicals? Again, all this information should be spelled out on your company website, but it also needs to trickle down to the end consumer in a direct and clear point-of-purchase presentation.

Wrap it up

If you package your produce, are you using easily recyclable, degradable and/or compostable materials? I’m a big recycler and home composter. If I can avoid buying produce in packaging I will — but if it’s unavoidable then I want to make sure the packaging is as low-impact as possible. There is nothing more supremely frustrating to me than to not be able to find clear recycling or composting instructions for the container or wrapper.

In fact, I find that many of the packages sold at “organic” or “natural” food stores are completely void of recycling information. Too often the materials used aren’t recyclable or compostable at all. Using materials that aren’t widely recyclable or require special facilities to sell organically grown produce seems counterproductive, and it sends a conscious message to me as the consumer. If you are using sustainable, recyclable and/or compostable packaging, make it more than clear on the label and provide instructions for disposal. It may not seem like it, but this is an important marketing message you need to communicate. The lack of this information does not inspire confidence.

Don’t make it too hard for customers to listen to what you have to say about what you grow and how you grow it. When it comes to contemporary marketing, your goal is to break through all the static with a message that is specific, clear, and truthful.

Leslie (CPH) owns Halleck Horticultural, LLC, through which she provides horticultural consulting, business and marketing strategy, product development and branding, and content creation for green industry companies. lesliehalleck.com