In October, New York-based vertical farming company Farm.One launched an in-store farm at Whole Foods in Manhattan. The farm will grow Blue Spice basil that consumers can purchase to take home, eat on a pizza served in the store and in a Whole Foods Mule, the store’s take on a Moscow Mule.

The basil will be grown in a three-level deep water culture hydroponic system.

According to Farm.One founder Rob Laing, the project is similar to what indoor mushroom grower Smallhold previously did with Whole Foods.

Produce Grower: How did this new farm project come to be? 

Rob Laing: We think we’re really good at building farms for small spaces and farms that work in cities. And I think we are very different than most vertical farming companies in that we tend to grow a specialty range of produce, more miniature produce, more interesting kind of stuff. And we like to create farms that are viewable to the public. So this opportunity to work with Whole Food was sort of perfect for us because it was an opportunity to put something in their newest store. We’ve been working with them on this for quite a few months, trying to put together a design that works well with the store and something that really is very open and bright and attractive to the customer. 

PG: How did you choose Blue Spice basil for the mini-farm?

RL: We grow a lot of different types of basil. The one most consumers are familiar with is the Genovese basil.

Blue Spice has this amazing bubblegum, berry kind of aroma. It’s really strange — almost a sweet aroma as opposed to a traditional basil. So we thought it was a really interesting crop. It’s something that you can smell that is different and taste that is different as a consumer, even if you don’t know that much about produce.

It also grows really well. It’s a very flourishing variety. It grows these beautiful purple flowers that feature nicely in the cocktails. We thought it was something that was a little off the beaten track, but at the same time accessible for consumers. 

PG: What is it like working with Whole Foods, which is a big company in its own right, but is owned by Amazon? 

RL: They were just really enthusiastic about what we were doing. They’re a huge company, but there are real people there. They see a lot of small food producers, so for them to come to our farm meant a lot.

For Chris [Manca, Whole Foods’ local forager] to come to our farm, it is like a chef visiting us. He knows what’s going on and the upside of the technology. We’re not really coming into this like a bulk supplier. It was more of ‘let’s create something that’s stunning.’ 

In this second article of our five-part series on culinary herb research at Michigan State University (MSU), we will highlight the results of pushing the lighting and carbon dioxide envelope during the production of dill, parsley, and sage seedlings indoors without sunlight. To see part one, click here.

Increasing light intensity up to a certain species-specific point increases the yield (ex. fresh mass) and quality of many crops including culinary herbs. However, what if adding supplemental lighting in the greenhouse or increasing the intensity of sole-source lighting in indoor (vertical farms, warehouses and containers) production for the entire crop production duration is not economically feasible? Dynamic environmental control, or adjusting the growing environment based on plant age or production stage, could be more efficient in enhancing crop yield and quality and reducing production costs.

 With more expensive capital and operating costs for indoor specialty crop production, short duration and high-density crops are potentially higher-profit options. With this higher cost of production comes increased environmental control capabilities, including the ability to manipulate sole-source light intensity and quality, temperature, humidity, and carbon dioxide (CO₂) concentration. The question is, how do we leverage this control effectively?

In this study, we focus on indoor herb young plant production, from seed sowing to transplant. Our hypothesis was that increasing production inputs such as light and CO₂ during the young plant stage could give those plants a head start for the finishing stages. Additionally, during young plant production, plant density is much higher than during finished production. For example, a 200-cell tray of culinary herb seedlings can be produced in two weeks in the same area that three to 20 plants can be grown during finishing stages and harvested in three weeks. If the higher operating and capital cost of indoor production can be spread across a larger number of plants with a shorter production duration, the cost per plant is much less.

 In our previous indoor seedling production research focused on basil, we determined that seedling fresh mass was 284% greater when grown under 600 µmol·m^?2·s^?1 (daily light integral [DLI] of 35 mol·m^?2·d^?1) compared to 100 µmol·m^?2·s^?1 (DLI of 6 mol·m^?2·d^?1). However, increasing CO₂ concentration did not increase fresh mass of basil seedlings. More importantly, after being transplanted into a common greenhouse environment, an 80% increase in fresh mass persisted through harvest. This was a large increase in harvestable yield and we wanted to determine if other commonly grown culinary herbs would have a similar response.

Seedling production

We selected three popular culinary herbs, dill ‘Bouquet’, parsley ‘Giant of Italy’, and Sage ‘Extrakta.’ Seeds were sown in 200-cell rockwool cubes and placed in walk-in growth rooms with CO₂ concentrations of 400, 800 or 1200 ppm. Each chamber was equipped with light-emitting diodes (LEDs) that provided four different light intensities of 100, 200, 400, and 600 µmol·m^–2·s^–1 (Fig. 1). The LEDs were on 16 hours each day to create DLIs of 6, 12, 24 and 35 mol·m–2·d^–1. After three (dill), four (sage), or five (parsley) weeks after sowing, data was collected.

Increasing indoor light intensity from 100 to 600 µmol·m^–2·s–1 had different effects depending on the genera and CO₂ concentration. The fresh mass of parsley seedlings was 12% greater when grown under 100 µmol·m–2·s–1 compared to 600 µmol·m^–2·s^–1 (Fig. 2). The opposite trend occurred for sage seedlings where those grown under 400 µmol·m^–2·s^–1, had 17% greater fresh mass than those grown under 100 µmol·m^–2·s^–1 (Fig. 3). The influence of light intensity on dill fresh mass depended upon the CO2 concentration provided (Fig. 4). When CO2 concentration was elevated to 1200 ppm, plants grown under 600 µmol·m^?2·s^?1 had the greatest fresh mass. When CO₂ concentration was not elevated above ambient levels (400 ppm), plants grown under 400 µmol·m–2·s^–1 had the greatest mass.

Besides fresh mass, another important factor to consider is seedling compactness. Seedlings grown under 100 µmol·m^?2·s^?1 tended to be floppy, elongated, and tangle together. Increasing light intensity resulted in more compact and sturdy seedlings that would potentially utilize less labor or be easier to automate transplanting.

Crops responded differently to elevated CO₂ as well. Increasing CO₂ concentrations did not influence the fresh mass of sage, but did increase the fresh mass of parsley. The greater CO₂ input increased fresh mass of dill only when the light intensity was high (600 µmol·m^–2·s^–1).

Finished production

You may be thinking: Great, you have increased fresh mass at transplant, but that is not the product I am selling! That was our thought as well, so we transplanted these seedlings into deep flow raft hydroponic systems and grew the plants in a common greenhouse environment with an average daily temperature of 73 °F and DLI of 14 mol·m–2·d^–1 for four (dill and sage) or five (parsley) weeks.

We found that elevating the CO2 concentration during the seedling stage did not influence any of the crops at harvest. However, increasing light intensity from 100 to 400 µmol·m^?2·s^?1 increased dill and sage yield by 47% and 69%, respectively (Fig. 5). Additionally, when dill seedlings were grown under higher light intensities, the stems were thicker and plants were less floppy at harvest (Fig. 6).

Efficiency implications

By sowing seeds in a 200-cell tray (200 in² per flat, 1 in² per cell), the planting density is 144 plants per ft2. Seedlings were transplanted 8-in apart with a planting density of 2.25 plants per f². Therefore, the planting density was 64 times greater during seedling production than finished (harvest) production. Additionally, in this study, the duration of dill seedling production was 3/4 that of finishing (three weeks compared to four weeks). Taking both the increased planting density and shorter production duration into account, the increase in sole-source lighting cost per plant could be discounted by 64 (sage) to 85 (dill) times during seedling versus finished production.

Therefore, in this case, the cost per plant of increasing the light intensity from 100 to 400 µmol·m^?2·s^?1 during propagation was ~4 to 5% that of the cost during finished production. Since the increase in yield at the finishing stage was 47% (dill) and 69% (sage) greater when seedlings were grown under 400 µmol·m^–2·s^–1 compared to 100 µmol·m^–2·s^–1 (24 compared 6 mol·m^?2·d^?1), increasing light intensity during seedling production increases subsequent yield while reducing input costs.

The bottom line

Elevating CO₂ concentration during young plant production did not have a long-term effect on plant growth or harvestable yield of the culinary herbs we have investigated. However, increasing light intensity during dill and sage seedling production, but not parsley, is a more effective strategy to increase subsequent yield.

Kellie Walters was a Ph.D. student at Michigan State University (MSU) and is now an Assistant Professor of Controlled Environment Plant Physiology in the Department of Plant Sciences at the University of Tennessee and Roberto Lopez is an Associate Professor and Controlled Environment/Floriculture Extension Specialist in the Department of Horticulture at MSU. The authors gratefully acknowledge Sean Tarr and Nate DuRussel for assistance, Fluence Bioengineering for LEDs, JR Peters for fertilizer, Grodan for substrate, Hydrofarm for hydroponic production systems, and MSU AgBioResearch Project GREEN, MSU Graduate School, and the USDA-NIFA for funding.

What does the variety market look like for growers who are considering changing their tomato offerings?

We’ve got two we’ve introduced a few years ago — Garden Gem and Garden Treasure. Garden Gem was actually featured in Slate Magazine and labeled the tastiest tomato by a group of researchers. They are from Dr. Henry Klee at the University of Florida. Really, what Dr. Klee has done has gone back and really reworked tomatoes. It was part of his research and he went and characterized everything that makes a tomato taste good. What he found at the time was that none of the top grocery store options were tasty. He used that data and essentially married the great taste of an heirloom with modern disease resistance. These varieties also thrive in the heat. Katie Stagliano from Katie’s Krops in South Carolina goes on and on about this.

If you’re a grower looking at this market, what is the advantage of getting ahead on varieties and staying ahead of the trends?

We’re taking the same approach as we do with flowers and now doing it with vegetables. So, we’re looking for the most successful varieties with the consumers with the extra caveat that it needs to taste amazing. It’s got to blow people away and that’s what people are looking for. We were so lucky to link up with Dr. Klee because he had been trying to get these introduced to the market and had no luck despite consumers reaching out to him on Facebook and basically demanding them.

How does Proven Winners see the current tomato market and the opportunities it can offer those interested in it?

Tomatoes are the king of all of the vegetables. It’s a top seller and between tomatoes and peppers make up the majority of the home garden market. But now with COVID — that’s the big thing — we’re finding millions of new gardeners out there and we look at edible gardening as the gateway drug of gardening. That’s the first thing they are going to try — they are going to plant a tomato, plant a pepper, and having that category was important to me because it was something I saw my friends doing and what I saw millennials doing. They weren’t starting with a petunia; they were starting with vegetables. For growers, it is a premium variety, so there is only so much market capitalization available there. So it’s about deciding how much of a premium crop you want to plant and using our pull-through marketing and the marketing Dr. Klee has done to gain another advantage.

Atlas Manufacturing greenhouse sales rep Stuart Sumner says interest in new structures has never been higher. “We have customers in various sectors of this industry that had very productive years despite COVID-19,” he says. “Due to this, we are seeing more interest and enthusiasm heading into 2021.”

According to Sumner, the following five trends in greenhouse structure innovation seem to be popping up more and more across the projects he has worked recently:

1. Positive pressure (PP) ventilation cooling — Produce growers are taking a closer look at PP ventilation systems, especially in hot and humid climates where a traditional system that draws more humidity from outside is not ideal, Sumner says. “When growing in a high humidity climate, adding additional humidity through an evaporative cooling system in a negative pressure setting can have a detrimental effect on crops,” he says. “You will be much more likely to experience issues with fungal pathogens and have a greater need for humidity control equipment.”
2. Supplemental lighting — Sumner answers a lot of questions about supplemental lighting during the design phase. “There is a lot more interest surrounding LED options for supplemental lighting and the technology itself is rapidly evolving,” Sumner says. “Companies are constantly innovating these lights to be more energy efficient and effective at targeting the desired spectral wavelengths of PAR light. The traditional HPS fixtures may be the most commonly used at this time, but I believe the LEDs may overtake them as the most frequently used at some point in the future.”
3. Taking sidewall height even higher — Growers are also interested in installing the highest sidewalls structurally-possible in new builds, Sumner says. This strategy allows for a larger area at the top of the structure to push and store hot, humid air far away from the plant canopy down below, he says. “It’s true that the higher you can go [on sidewalls], the more optimal situation you are in from a ventilation and cooling perspective,” Sumner says. “With everyone wanting to get those sidewalls as high as they can be, I like to joke that by 2050 we’ll all be growing crops in skyscrapers.”
4. Hydroponic grow systems — From the ubiquitous “Dutch” bucket style for peppers and tomatoes to the popular vertical farming and deep-water culture growing systems, grower interest in replacing soil with growing media and oxygenated water has never been higher. “We are seeing commercial growers utilizing hydroponic grow systems such as Nutrient Film Technique (NFT) systems that can reduce the expected harvest time considerably when compared to more traditional grow methods. I believe we will begin to see this system become more popular as we move forward.”
5. Insect exclusion structures — Companies like Atlas are recommending growers, regardless of crop, consider built-in insect protection measures. Sumner refers to these design add-ons as “insect exclusion structures.” Extending the frame of the greenhouse out on opposite ends a set distance, and then covering that area between the ventilation equipment and the outside with woven insect proof materials helps prevent insect intrusions from the cool outside air. “This is something that we really think is worth a grower’s investment in the long term. It will save you money,” he says.