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

This year, the Hydroponic Production Primers columns will focus on key points for producing some of the most popular food crops grown in greenhouses and controlled environments. First up: peppers.

Genetics: The most popular type of pepper (Capsicum annuum) grown is the bell pepper, standard block fruits. In addition to the standard, large bell peppers, snacking or mini peppers are increasing in popularity. Nearly all peppers hydroponically produced in greenhouses and controlled environments are sold ripened and colored, not green. Red is, by far, the most popular color, followed by yellow and orange.

Production systems: Peppers are commonly produced in systems that are most well-suited for vine crops, including stone wool or coconut coir slabs and Dutch buckets (Fig. 1) filled with perlite. Some producers also grow peppers in large nursery cans or containers filled with a loose peat-based growing substrate.

Propagation and young plant production: Peppers are propagated by seed. They should be sown in small propagation cells or cubes for germination. Air temperature and substrate temperature should be maintained in the upper 70s (°F) for seedling germination. During propagation, a nutrient solution with a low EC around 0.5 mS/cm should be used. When transplanting seedlings into 4-inch stone wool or coconut coir blocks, the root cube can be rolled onto its side to bury part of the pepper stem; this should not be performed with grafted plants.

Nutrient solution: The nutrient solution for pepper plants can be divided into two different phases: early, and full production. Once the young plants are transplanted into their final systems, stronger fertilizer solutions (2.0-2.5 mS/cm) than those applied during seedling production are used. During this early phase after transplanting into systems, plants are establishing in production systems and vegetative growth is promoted. To promote vegetative growth during establishment, a higher concentration of nitrogen is used. Once plants are established in production systems, the nitrogen concentration can be decreased, while the concentration of potassium should be increased.

Temperature: Target air temperatures during the day for peppers is 70-73° F; while shade can be used to reduce the greenhouse temperature in the summer, the lower light intensity resulting from the shade when air temperatures are warm may result in fruits that can’t fully develop. Night temperatures from 60-64° F are conducive to the development of flowers and fruits. If night temperatures are too warm, flowers may abort from stress.

Light: During the late fall, winter, and early spring, peppers respond positively to the increased light intensity from supplemental lighting and yields can be improved. Supplemental lighting is not required during the later spring, summer, and early fall.

CO2: Peppers respond positively to supplemental carbon dioxide, both during the seedling and finishing stages. The use of supplemental CO₂ is especially beneficial during times of the year when greenhouses are not venting to replenish CO₂ concentrations in the greenhouse.

Pollination: Peppers do not require pollination for adequate fruit production. However, by pollinating the quality of fruit can be increased while production time and disorders are decreased. While both hand and bee pollination are effective, bumblebees are a more efficient choice.

Pruning and training: Peppers are most commonly grown on plants with two stems trained vertically in the greenhouse (Fig. 2). After several leaves have unfolded and expanded, pepper plants will naturally bifurcate into two stems. These stems are trained on a trellis like tomatoes and other vine crops. However, unlike tomatoes the stems are not leaned or lowered and are trained straight up. Pepper flowers form in leaf axils. The flower formed where the stem splits or bifurcates is removed, as are the flowers formed on the first leaf axil on each of the two stems; the flower on the second leaf axil or node is kept and a fruit can develop. After this, flowers are removed from every other axil/node, allowing a flower to open and fruit to form on every other node. Side shoots, or suckers, are not entirely removed from plants. Rather, they are left on plants but pruned back to leave two leaves.

Pests: The most common pest found on hydroponically grown peppers in greenhouses are aphids; the green peach aphid is the primary pest, though other aphid species can also infest peppers. Honeydew is one of the key symptoms of an aphid infestation and is problematic because it needs to be washed off fruits prior to marketing or can become a food source for sooty mold on foliage and fruits. Two-spotted spider mites are another problematic pest. Signs of mite infestations include webbing and speckling during the early stages and, as the infestation intensifies, leaves become brown and additional webbing is apparent.

Diseases: Diseases including Botrytis, Pythium and Rhizoctonia can all affect pepper crops. While pesticides can be applied, good greenhouse sanitation (removing dead and infected plant material), environmental conditions (adequate air movement, minimizing excessive humidity) and cultural practices (regular watering and fertilization) are the best way to prevent these diseases. In addition to bacteria and fungi, there are several viruses which can adversely affect peppers, including pepper mild mottle virus, tomato spotted wilt, and tobacco mosaic virus. Dipping hands in a milk solution can deactivate any virus that may be on your hands and can minimize spread between plants that are handled. Additionally, purchase seed from a reputable supplier that has been tested to be virus-free.

Physiological disorders: Flower abortion can be a common problem and can be the result of several problems. First, extreme warm temperatures can cause flowers to drop, and is most common during the summer months when outdoor temperatures are warmest. However, if the EC in the root zone gets too high, this can also cause flowers to abort. When fruits are exposed to bright and/or intense lights sunscald (Fig. 3) can occur. To avoid sunscald, steer plants in a vegetative direction to enhance leaf growth to shade the peppers. Also, leave an additional leaf or two when pruning suckers to provide more shade for fruits. Deformed fruits can result from poor pollination, especially when growing temperatures are cool. The use of bumblebees may help improve pollination and subsequent fruit growth. Finally, dark lesions that develop into necrotic tissue on the bottom of peppers results from blossom end rot, caused by a calcium deficiency. While the nutrient solution may contain insufficient calcium, it can also occur when there is sufficient calcium present, but uptake is diminished due to low light or high humidity.

Harvesting: Fruits are ready for harvesting once they have approximately 85-90 percent of their surface colored. Fruits should be removed from plants using a sharp knife; if you try to simply pull the fruit off the plants, both the fruit and plant can get damaged.

Postharvest care: Peppers should be cooled using forced air cooling. Fruits should not be hydrocooled, as the cooling solution can get inside the pepper fruit and cause a rot. Depending on how fruits are marketed, they may either be placed in cartons, clamshells, shrunk-wrapped polystyrene trays, or bags. Store peppers in a cooler at 45° F and maintain a relative humidity between 90-95 percent.

Christopher (ccurrey@iastate.edu) is an assistant professor of horticulture in the Department of Horticulture at Iowa State University.

The Produce Marketing Association held its 2017 Fresh Summit Convention & Expo in New Orleans this past October. At the event, PMA CEO Cathy Burns gave her State of the Industry address, in which she spoke about news and trends that span the entire produce industry. Part of her address focused on several consumer-facing companies and technologies. Here are some of them:

• In 2016, smart appliances, including ovens and lunchboxes, were all the rage. In fall 2017, Panasonic released a small refrigerator prototype that comes when you call it, and comes equipped with a Roomba-like detection sensor.
• Wholesome Wave, a nonprofit that provides “prescription” fruits and vegetables to consumers, broadened its reach. “With 700 locations across 46 states, Wholesome Wave has analyzed its partners’ data and found that with just a small increase in fruits and vegetable consumption, roughly 48 percent of the participants reduced their body mass index,” Burns said.
• Companies such as Helix and Habit are using human DNA to improve consumer health. “Our own report found that although consumers’ desire to know their genetic code that connects to diet and lifestyle is still in the very early trends, there’s actually a strong interest among consumers, marketers and the scientific community when it comes to DNA profiling,” Burns said.
• Another company operating in the DNA space, albeit focused more on leisure, is Vinome, a wine recommendation service that tests consumer DNA and ships vino to them based on the test results.
• Italian grocery store chain Coop Italia has adopted technology that brings up detailed product information when consumers move their hands over the product.
• Chowbotics introduced Sally The Salad Robot, a quasi-vending machine that makes salad using an array of ingredients — and faster than a human can. “Humans are still needed to prep the ingredients that actually go into the robot’s cannister, which has the ability to make more than 1,000 salads, created from Sally,” Burns said.
• Lastly, UNICEF developed the Kid Power Band, which converts the steps children take into food donations for hungry children. “So far, more than 5 million packets of food have been donated to more than 30,000 severely malnourished kids,” Burns said.

Photo courtesy of Agrivolution

Agrivolution Super Slim Full-Spectrum Triple-Band LED

Do your crops need a boost of light? Look no further. Triple-Band LED Flatbar is a professional-grade, super slim horticultural grow light. The energy-saving, full-spectrum LED utilizes advanced phosphor conversion technology to produce white light that is closer to the natural light for your crops. Designed specifically to promote photosynthesis, it is an ideal solution for greenhouse supplemental lighting, seedling and clone propagation, microgreens and vertical farming. Consult us to learn how Triple-Band LEDs can benefit your farm. — agrivolution.co

Photo courtesy of BLV Licht

BLV top-lighting luminaire

The BLV top-lighting luminaire is optimized for high durability and minimum daylight interception. The open reflector design guarantees optimal lamp performance and easy maintenance. The brand-new luminaire comes with a BLV power supply, which is EMI/EMC compliant and equipped with all necessary safety features. The power supply operates the double-ended BLV HPS and MH lamps of 600 W, 750 W and 1000 W, which are known for their best-in-class PAR values, PAR maintenance and durability, Moreover, more than 70 logs can be read-out wirelessly with a handy device. A simple software adjustment allows easy exchange between power rates and therefore offers a great flexibility and reliability. —www.blv-licht.com

Photo courtesy of Illumitex

Illumitex PowerHarvest

The PowerHarvest 14 from Illumitex now offers up to 2.2 umol/J and 1300 PPF. The PowerHarvest is a high-power LEDs fixture that maximizes canopy penetration and optimal plant growth from both vegetative and bloom stages. Designed and tested specifically for indoor grow operations, including greenhouses, sole-source facilities, and other CEA applications. —illumitex.com

Photo courtesy of PARsource

PARsource Phantom Commercial Double-Ended Light System

The PARsource Phantom Commercial DE Light System is flexible, economical and powerful, and ideal for greenhouse operations. An internal electronic microprocessor allows the ballasts to run at a higher frequency, creating higher lumen output. Choose between open, enclosed or super deep reflector options depending on your specific needs. The system comes in multiple voltages with boost and dimmable options, has smart shut-off technology, and can operate as an attached or remote unit. A premium double-ended Agrosun lamp is included. — parsource.com