Managing mineral nutrition for hydroponically grown crops is essential for maximizing crop productivity and quality. Deficiency symptoms can occur when there are insufficient nutrient concentrations in solution. However, it is also possible to observe deficiency symptoms even when there is a sufficient concentration in the nutrient solution due to nutrient antagonisms. This article will focus on the relationship between potassium (K), calcium (Ca) and magnesium (Mg).

Understanding K, Ca and Mg

The relationship between K, Ca and Mg is an important one for hydroponic operations. To understand how to manage the relationship between these nutrients it is important to review a little bit of their chemistry. When fertilizer salts are dissolved into solution, the salts dissociate, and nutrients are available in their charged ionic form. All three of these nutrients — K, Ca and Mg — are all positively charged ions, or cations. Furthermore, in their ionic state they have a similar charge or valance. K is missing one electron and is a monovalent cation (K+). Ca and Mg are missing two electrons and are divalent cations (Ca2+ and Mg2+). In addition to their ionic charge and valance, Ca and Mg nutrients are all taken mass flow when water is taken up by plants. Due to the similar chemical properties of these elements, as well as some being taken up by the same processes, these nutrients can compete with one another.

Developing antagonisms

A nutrient antagonism is when an excessive concentration of one nutrient inhibits the uptake of another. Since K, Ca and Mg have similar properties, and are taken up in a similar fashion, too much of one nutrient can inhibit the uptake of another nutrient. For example, if the concentration of Ca gets too high, it can impede the uptake of Mg. Or if the K concentration gets too high, Ca uptake can be inhibited. The ideal ratio of K:Ca:Mg to each other in hydroponic nutrient solutions to avoid uptake varies a bit, but is usually three to five parts K and Ca to one part Mg (3-5K:3-5Ca:1Mg). However, this tends to vary with plants. For example, lettuce and leafy greens do well when Ca and K are balanced with each other. Fruiting crops do well with a greater proportion of K.

Antagonism-induced nutrient deficiencies can cause a variety of hydroponic food crop disorders, ultimately reducing productivity and marketability in crops. For example, a K deficiency in tomatoes can results in yellow shoulders, where fruits do not fully ripen. A Ca deficiency in tomatoes and peppers can result in blossom end rot and produces fruits with necrotic portions of fruit where the calyx or petals of the flower were attached, whereas Ca deficiencies in lettuce and other leafy greens can cause marginal necrosis or “tip burn” on leaves. Finally, Mg deficiencies cause chlorosis on leaves and, while commonly observed on tomato plants, it is most problematic for basil.

Creating and maintaining a balance

To keep K, Ca and Mg in balance in nutrient solutions, the water, fertilizer and pH adjusters used to make up and maintain nutrient solutions should all be evaluated. By starting out with the right proportions of K:Ca:Mg, and maintaining them throughout production, antagonisms and the deficiencies they induce can be avoided.

The most proactive approach to managing nutrient antagonisms after mixing fertilizers is to perform regular nutrient solution analyses."

In my area of Ohio, changes in design trends are easy to see. Most of the homes in the inner-ring Cleveland suburbs are at least 100 years old, with a few new townhomes and new constructs sprinkled in. And I’ve seen plenty of them in the past few weeks in my hunt for a new home.

In recent years, Cleveland’s housing market has boomed, and now century homes are undergoing extreme renovations as owners update them for a fast-moving market. When taking stock of what’s on the market, it’s not uncommon to visit one house with interior designs from the '90s (or '80s or '70s) and then visit another with a completely redone interior with modern design elements. It’s a stark contrast between the old trends and the new.

Patterned wallpaper and detailed woodwork are out, and simple, neutral colors are in. Clean lines, open floorplans and simple designs with geometric shapes are taking over indoors, just as they are in the newly constructed homes in the area.

Just like produce packaging, less is more these days. A quick glance at your local grocery store shelves shows the same trends in redesigned packaging: more open space, fewer images, less detail work and just a generally cleaner feel.

While changing designs in housing décor and packaging aren’t going to make or break my decision in buying groceries (or homes), it’s always going to be a factor. But, as you’ll discover in our cover story starting on page 16, it’s not just looks that matter. Consumers are looking for sustainable, recyclable options that look good, aren’t wasteful and showcase what’s really important: the produce.

Just as you wouldn’t buy a good-looking house with a sinking foundation, you wouldn’t buy produce that doesn’t look fresh and delicious. It’s what’s inside that counts the most, of course, but I’d be lying if I said I didn’t judge a book by its cover — at least a little bit.

When visitors walk into Vertical Harvest’s luminous three-story glass building for tours, they’re stepping into the architectural brainchild of Nona Yehia.

The singular combination vertical farm and greenhouse grows specialty greens, leafy greens, microgreens and tomatoes using LED lights, robots and moving hydroponic carousels.

An eclectic mix of workers, many of whom have intellectual and physical disabilities, take care of the futuristic farm and its many technologies, growing some of the freshest produce around.

The Jackson, Wyoming, grower aims to provide those with disabilities opportunities for upward mobility, says Yehia, who is co-founder and CEO. The operation, she says, provides an example of how farms can change the perception of the abilities of workers with disabilities. Workers who often only have opportunities in entry-level jobs thrive here in an environment where they can help solve some of the world’s most pressing problems, including land and water shortages and other environmental issues.

“It’s the way Vertical Harvest is a team that’s conceived of the company that’s really different, saying that you can do well by doing good, and that it actually benefits the bottom line of the business to do so,” Yehia says.

She says Vertical Harvest would never open a farm without helping an underserved population, whether that be people with disabilities or other underserved groups, such as refugees or veterans. And Vertical Harvest aims to expand; for example, it is developing a vertical farm project in Lancaster, Pennsylvania.

Vertical Harvest maintains high standards for its produce, too. Daily, it regulates three separate growing environments that, with the glass walls, are influenced by the outside environment. It follows integrated pest management protocols and offers a varied product mix — including 30 different microgreens varieties — catering to chefs, high-end restaurants and grocery stores.

“I like to say that people come to us because of our mission, but they come back because of the quality of our produce,” Yehia says.

The mission

From the outset, passions about social issues and the environment influenced Yehia, Caroline Croft Estay and Penny McBride to found Vertical Harvest in 2010.

When she met McBride at a party in 2008, Yehia was well established as an architect, with 13 years under her belt at E/Ye Design, where she was partner with Jefferson Ellinger. While her architectural knowledge and experience helped her design a distinctive greenhouse-vertical-farm, she also wanted to address some of the social problems in America.

“I have a brother with developmental disabilities. … This country’s done a very good job of nurturing and including this population during education, but when it comes to employment, you’re on your own,” she says. Her focus on nurturing and inclusion would prove essential to Vertical Harvest’s mission.

McBride, a sustainability consultant, was looking for unique ways to sustainably and efficiently grow produce, Yehia says. Jackson imports most of its food, but a foodie scene in the short summers illustrated a need for local, fresh food. Many consumers were not satisfied with produce that was shipped in and sold in local grocery stores.

While the demand for better product was there, it proved a challenge to find land where they could build a controlled-environment farm. The surrounding public lands minimize areas that can be used for construction. “Ninety-five percent of the land that is developable is already developed,” Yehia says. “So, locating a greenhouse that might serve our downtown community was actually kind of a difficult proposition.” They settled on a tenth of an acre next to a parking garage and looked to the skies for more real estate.

To build up Vertical Harvest’s social mission, Croft Estay, a longtime employment facilitator, looked to the Employment First model, which the U.S. Department of Labor says is based on the idea that everyone, including people with disabilities, should be able to work well-paying jobs in integrated workplaces that offer benefits and opportunities for advancement. Croft Estay also followed an approach called customized employment, which involves a personalized relationship between employer and employee that helps both parties.

From there, Croft Estay developed Vertical Harvest’s “Grow Well Employment Model,” which Yehia says involves spreading customized employment and Employment First throughout the company’s culture. (Croft Estay is now director of diversity and inclusion at Vertical Harvest; McBride is a shareholder.)

In addition, Yehia and her colleagues were inspired by Arthur & Friends, a hydroponic greenhouse in New Jersey that Wendie Blanchard founded to employ people with disabilities. Blanchard named the operation after her nephew Arthur Blanchard, who has Down syndrome and enjoys growing produce with workers both with and without disabilities, according to New Jersey Monthly.

“She’s been consulting around the country for people who want to be more inclusive in their growing practices and employment practices, so that was really an inspiration from the very beginning,” Yehia says.

People with disabilities are the largest minority group in the United States, Yehia notes, and more of them need opportunities to excel in the economy. “It’s an important thing to be able to bring together all the research and understand, being that this is surrounded around this effort into corporate cultures,” she says.

Offering empowerment

Vertical Harvest opened its 13,500-square-foot facility in 2016 to meet the needs of its rare mountain town. Nestled in the Jackson Hole valley, Jackson lays about 5 miles from Grand Teton National Park and about 80 miles from Yellowstone National Park. It’s a ski town and many people come and go, Yehia says. Some move there after college, then eventually leave for other opportunities.

“There’s a very transient employee base,” she says. “On the other hand, there’s a group of people who live and work here, or want to find consistent employment here, but experience very high unemployment.” She says among people with physical and intellectual disabilities, there’s about a 78% unemployment rate.

Nineteen of Vertical Harvest’s 34 employees have disabilities. That level of inclusion provides a healthy balance of different perspectives, Yehia says.

“What happens sometimes is that you might employ one or two people with a form of a disability, and then in the end they feel more segregated because they are almost separated out from the rest of the culture,” she says.

In addition, Vertical Harvest uses language that is meant to be empowering. Rather than saying people have “disabilities,” they prefer to say they have “different abilities.” “It’s not like we’re scared of the word ‘disability,’” Yehia says. “But we prefer the word[s] ‘different ability’ because we work toward bringing out people’s ability.”

Every day, Emily Churchill, director of production, visits the departments of tomatoes, lettuce, microgreens and integrated pest management. Throughout the process, she works with people with various abilities.

“My senior grower for lettuce [Michelle Dennis] is one of our employees with a different ability, and I talk to her probably five times a day, making sure the harvest is on track and the transplanting and all of that stuff — whereas some of our other employees who work in microgreens have their routine down and they are less social and they just like to put their headphones in and seed,” Churchill says.

Decision-making at Vertical Harvest follows a triple bottom line of profit, people and the planet, Churchill says. “Maybe one of our managers will take 30 minutes out of her day to sit down and have a one-on-one meeting with her employee to check in or to ask what they need help with and what they’re enjoying,” she says. “On paper, that looks like we’re losing 30 minutes of work that day, but actually, that’s 30 minutes that is going to one of our triple bottom lines.”

The energy in the greenhouse reflects the resourceful collaboration among its team, Churchill says. “I’m reminded of how revolutionary it is when new people come into the greenhouse and they’re kind of blown away by what we’re doing,” she says.

Glass-box transparency

Vertical Harvest’s glass-walled design allows it to use the external environment to its advantage as much as it can, Yehia says. Borrowing ventilation, heating, air conditioning and lighting from the outside saves energy. But these clear walls also reflect the business’ openness.

“We’re in a glass box, so the transparency with which we run our company is key to every element of Vertical Harvest,” she says.

The farm quickly makes its produce available at retail and consumers are noticing, Churchill says. “For us to be able to provide food that was harvested the day that someone buys it or the day before you buy it, is so different compared to anything else you can get in a grocery store,” she says. “And I think you can really taste it when you eat the product.”

Vertical Harvest started working with the Teton County School District on a program called “Fancy Food Fridays.” Every Friday for two months, the students tried a different microgreen. Then, if their parents would bring them to the farm, they would already be familiar with the product.

“When parents would come to the greenhouse with their kids, their kids were like, ‘Hey, Mom, this is my favorite microgreen,’ which, if you can imagine that, it’s pretty exciting, being able to introduce kids to this very, very new and important crop,” Yehia says.

Vertical Harvest also hosts a hospital market with St. John’s Hospital every week and it’s working with the University of Wyoming on a nutritional study to explore the health benefits of local produce. Consumers not only value that Vertical Harvest provides local produce but that it conducts education and outreach, Yehia says.

“A consumer can really come and see all of Emily’s good work in her growing her lettuce, and then when they go to a grocery store, see us on the menu, they know exactly where that head of lettuce comes from,” Yehia says. “I think that’s a really important shift and why interest in our brand is growing — because it is really important that it is located in the heart of the community, not only for employees to be able to access it, but also our anchor institutions.”

Expanding the model

The management and operational cultures at Vertical Harvest are laying the groundwork for expansion to other cities, Yehia says.

“Everything that we build there, we always say, ‘Could we do this in Lancaster?’” she says. “’Could we do this in any other greenhouse that we’re going to?’ and ‘How would we share this procedure or this practice or policy with other greenhouses?’”

Many CEA growers build their farms around intellectual property or growing technologies, but Vertical Harvest takes a different approach, she says.

“We are operators; we are farmers, so we build our intellectual property on our standard operating procedures and in our employment model,” Yehia says. “And so that is really what we are always looking at — how do we communicate with each other, how do we track data, how do we make something more efficient?”

At Vertical Harvest, the workers who grow microgreens are among the first people in the industry learning how to grow it, Yehia says, providing an example of how the farm empowers its community. Underserved populations, she says, will be leaders in the communities where the operation plans to expand.

“In our town, that was about people with different abilities,” Yehia says. “In another town, it might be refugees or veterans.”

The project in Lancaster could start as early as 2020, Yehia says. Then, Vertical Harvest could bring its model to other cities in the United States and beyond.

“If you invest in the people and the materials of your community, then you really strengthen not only the local economy, but the ethos, and you really empower a community,” Yehia says. “And I think that is worthy of being part of every urban community, to be another kind of civic building that we look at, like a community center or a library even.”

Photo courtesy of Pure Flavor

Many people within and outside of the produce industry have questioned whether “organic” could ever win consumer hearts. While the industry hasn’t hit organic domination, prevailing winds are blowing in that direction. The Organic Trade Association’s (OTA) 2019 Organic Industry Survey reports that U.S. organic food sales hit $47.9 billion for 2018. Organic produce represents more than 36% of that total.

According to OTA stats, organic produce now accounts for nearly 15% of all produce sold in the United States. That’s up 5.6% from the previous year — more than three times the increase for organic and conventional produce combined. And fresh produce makes up more than 90% of those organic sales.

So, what does that mean for your operation? Whether organic is your livelihood or your competition, the market’s momentum can’t be ignored.

Savvy consumers look for organic brands

As chief marketing officer for Pure Flavor, an Ontario-headquartered greenhouse vegetable grower, Chris Veillon tracks industry trends. “We continue to see significant growth in consumer interest regarding organics,” he says. “There are some that swear by only purchasing organics. It’s a choice being made, and consumers are willing to pay 20% to sometimes 40% more for organic items.”

“Consumers are becoming collectively savvier about organic produce — where it is grown, by whom, how and specifically where,” Veillon says. “There seems to be more confidence in the organic greenhouse-grown space, where vegetables are grown in a controlled environment.”

Organic greenhouse grower Kevin Matthews stepped away from large-scale commercial greenhouse production to grow local organic greenhouse vine crops for direct-to-consumer, internet-based Kristin’s Farm Stand.

Matthews says increasingly savvy millennial consumers are intensely conscious of what they consume. “The biggest thing for them right now is getting away from pesticides, herbicides and fungicides,” he says. “To do that, they’re turning to organic brands.”

Organic production technologies take new directions

Throughout the industry, talk about production methods is trending toward hydroponics, aquaponics and vertical farms. In Wisconsin, organic greenhouse grower Superior Fresh is generating conversation.

Specifically designed around organic certification and commercial-scale technology, the grower integrates an indoor Atlantic salmon farm with a produce greenhouse. As separate buildings, the fish house and greenhouse share only water — nutrient-rich from fish.

Brandon Gottsacker, Superior Fresh president, believes aquaculture is the organic produce industry’s future. When an in-process expansion ends, the company’s organic leafy greens production should top 5 million pounds annually, with 100% of the nutrients provided from annual production of 1.5 million pounds of premium salmon.

Veillon predicts that new growing and harvesting technologies will alter the industry: “Due to scale and capital investment, the migration of traditional organics will be towards protected-culture environments to maximize yield and quality and to further remove the seasonality challenges that exist in some respects.”

Photo courtesy of Superior Fresh

Local, sustainable and safe gain traction

With organic interest climbing, Gottsacker is also focused on local, sustainable and safe. He believes those “four check boxes” will gain significance as millennials demand more sustainable, environmentally friendly foods. “These are the most important pieces of the puzzle moving forward in this industry,” he says. “All those things come into play at the same time.”

Veillon expects consumer interest to mature along with Millennial buying preferences. “They want something specific and on their terms: eco-friendly, less of a carbon footprint and something that will make them part of a greater force,” he shares.

For Matthews, local focus is crucial. Kristin’s business model enables online shoppers to buy whatever they want — in any quantity — from a collective of local producers. Then it’s delivered to their door each week. Merging local production with the ease of internet grocery shopping is key to meeting local-minded consumer needs.

Veillon adds that regionally based growing operations are becoming growth strategies. “Reducing food miles is one thing, but the power of local to the region is gaining more and more steam, season over season,” he says.

Desires for new eating experiences drive R&D

As organics hit the mainstream, consumers expect more choice in types of produce and diversity within familiar categories. One look at Superior Fresh’s line of greens tells the story. From colorful, sweet baby greens to spicy, bold, full-flavored options, consumers choose from Power Blend, Might Mix, Midwest Medley and more.

“We’re doing a ton of R&D and trialing new varieties every day and sending them to our retail partners,” Gottsacker says. “We’re growing for taste, texture and color, and spending a lot of time putting mixes together and testing and seeing if they like them.” Organic strawberries and other new items are in the pipeline, all with fish house-generated irrigation.

Pure Flavor’s greenhouse-grown organic vegetables include on-the-vine, beefsteak and heirloom tomatoes, plus bite-size grape tomatoes and a snack tomato medley strong on flavor and color. Other snackable options include mini sweet peppers and mini seedless cucumbers.

“Snacking items in general are on trend, regardless of the type of product,” Veillon says. A “significant spike” in the company’s snacking tomato line prompted the organic Sangria Medley launch in fall 2019. He compares the tomato medley to a box of chocolates — rich with colors, shapes, sizes and flavors.

Competition with conventional pricing continues

Questions about organic costs and profit margins die hard. While Veillon agrees that organically grown vegetables can cost more to produce, he argues that, from a sales perspective, they can be just as lucrative as conventional greenhouse produce at certain times during the year.

“Consistency in grower supply, brand marketing and overall quality drives the needle upwards,” Veillon says. He adds that building consumer confidence is key, particularly for growers like Pure Flavor that evolved from being a seller to a vertically integrated greenhouse vegetable grower that controls 100% of the process from growing to promoting.

Superior Fresh aims to price in line with other premium growers, whether traditional or organic. “The product’s got to be affordable,” Gottsacker says. “I would like to think we’re doing it [at] a scale that allows us to have a more conventional or traditional price point. We don’t want to drive the price out of good healthy food. We want to do the opposite.”

Matthews holds that more efficient growing methods, informed crop selection and local distribution enhance profitability, but the bottom line is the same: Organic growers must compete with the conventional market on price to succeed.

Progress and passion determine the future

With momentum building in the organic produce market, CEA greenhouse growers are positioned to influence the industry’s course.

“We need to continue to breathe life into the produce industry with items that will not only resonate with retailers … but with consumers who are looking for healthy alternatives,” Veillon says. “A new pack style for an existing item won’t increase consumption. Fresh new items that are focused on convenience or enhanced flavor profiles can help ring the bell on several levels.”

Gottsacker plans to keep Superior Fresh at the leading edge of local and organic production. “The future comes down to how many people are going to be on this planet and how do you keep moving forward with providing people the healthiest, safest food possible,” he says. “We can’t slow down on driving technology on how to grow this type of food. It’s super important to keep moving forward and keep progressing.”

The author is a freelance writer and frequent contributor to GIE Media publications. Reach her at jolene@lovesgarden.com