For the past 10 years, Lauren Palmer, owner and farmer at Bloomsbury Farms, has combined food and family by growing organic vegetables for restaurants, grocery stores, farmers markets and a 300-member CSA community.

Located in Smyrna, Tennessee, Bloomsbury Farms is the product of Palmer's vegetarian roots, landscaper father and connection to nature. Originally starting off small with no intention of selling crops, her father reserved a booth at their local farmers market and changed everything.

“People were asking me how I did certain things and why I chose that vegetable,” Palmer says. “Some were even requesting vegetables that my grandparents used to grow. That relationship was exactly what I was looking for.”

With 400 acres of land, nine hoop houses and 15 acres of harvesting ground, Palmer grows more than 100 varieties of fruits and vegetables year-round. While heirloom and artisan vegetables are her favorite, strawberries, lettuce, squash, peppers and more are also cultivated and sold.

Once advised to make her greenhouses all the same, Palmer did the complete opposite. At different lengths, sizes and styles, the structures at Bloomsbury Farms differ with unique personalities and are strategically placed where the styles are best suited. This was easily done with Atlas’ line of various structures for different geographic locations and crops.

“Nine years down, no issues and I’ve never tried any other brand,” Palmer says. “I’ve had such great luck; there’s no need to change. They’re so friendly; they’re so nice to me and that’s what it’s all about. That’s how I’ve done business in food and anything else. I have to trust somebody and with Atlas it’s been a good relationship back and forth. I’m good to you if you’re good to me and Atlas has always been that.”

Bowery Farming, a New Jersey-based vertical farming company, considers its mission to democratize access to the high-quality food it grows in its farms. As more and more people move to urban areas, the company wants to make sure it can provide healthy, clean food. By investing in technological improvements, the company can grow better food for its customers and work toward improving efficiencies.

“People are moving to urban areas, but land and water for agriculture is scarce near those areas,” says Henry Sztul, SVP of Science and Technology. “So, Bowery developed a system to deliver 100 times more produce in terms of land productivity and uses 95% less water than a traditional farm.”

In addition to using less water and improving workflow with automation throughout the farm, a key part of Bowery’s technology investments are the LED lights it purchased from Fluence Bioengineering, by Osram. With the LED lighting, Bowery is able to produce crops such as leafy greens, herbs and bok choy year-round.

Currently, through Whole Foods stores and Amazon delivery, Bowery Farming sells its products in the greater New York City metro area, where traditional field agriculture isn’t possible and could limit residents’ access to fresh foods.

“There is a large market for fresh produce in the New York metro area and by growing less than 10 miles from NYC, we are able to deliver the purest produce imaginable within just a few days of harvest,” Sztul says.

“When it comes to LED in our farms, there’s been a lot of great research in academia, but scaling into commercial production has its own set of challenges,” Sztul says. “We value the ability to partner with Fluence to investigate the impact of various light intensities to provide the ideal recipe to grow plants with the best possible yield, flavor and taste. This capability doesn’t normally exist in indoor farming and this allows us to get every last leaf into our consumers’ hand imaginable within just a few days of harvest.”

In addition to offering landscaping services for the past 12 years, Hoen’s Garden Center & Landscaping sells a wide variety of plant products. The Holland, Ohio, operation not only grows vegetables and herbs such as tomatoes, basil and lavender, but also ornamentals, including begonias, pansies, gerbera daisies and an array of houseplants and tropicals.

Bob Hoen credits some of the business’ ongoing success to working with a trusted growing media sales representative. “He is a personal friend of mine,” Hoen says. “That’s what I like — he’s always here. He’s always looking at the crop, observing it, making sure I’ve got all my questions answered.”

In 2018, Hoen was looking for a growing media that he could rely on for his roughly 2 acres of production space. He trialed numerous mixes but wanted to stick to just one. He placed an order through his sales representative for GFM – PC-15 All Purpose Peat-Coir Mix from Lambert Peat Moss.

“I’m using it this year for every crop, which is veggies, flowers, perennials — you name it, I’m growing it,” he says.

Hoen says he has achieved healthy, fast growth of his crops using the product, which contains coconut coir and added micronutrients.

“With the coir, it holds more moisture,” Hoen says. “I think you’re watering a little less.”

With the PC-15, Hoen fertilizes at about 150 parts per million instead of the 100 parts per million he used to use. Plus, he’s been able to raise profits by reducing the amount of time the crops are on his benches.

“The crop is growing almost twice as fast with the extra micronutrients [in the growing media],” he says.

Recently, Hoen’s sales representative visited and the owner showed him Hoen’s herbs, which grow in 4.5-inch pots. Out of the roughly 150 herbs the greenhouse grows, they all performed well.

“They’re the best-growing herbs we’ve ever grown,” Hoen says.

Photo courtesy of Roberto G. Lopez

A cornerstone environmental parameter is light. The energy cost of heating a greenhouse transmitting “free” sunlight is often less than the energy costs incurred by sole-source lighting for indoor production. However, recent advances and increased efficacy of LED fixtures have made sole-source lighting and indoor production more feasible for certain types of production.

Why would anyone want to produce specialty crops indoors, void of natural sunlight? One reason may be extreme or seasonal weather conditions. Although we consider greenhouses to be controlled environments, it is often impossible to have consistent temperatures and light levels throughout the year. This in turn makes year-round production of food crops challenging. Indoor plant factories and vertical farms can be more precisely controlled, especially for difficult to grow crops (ie. tissue-culture transplants) and to improve uniformity and plant quality, and to reduce losses. High-value young plant production can be moved indoors for the same reasons.

Though young plants such as plugs can be successfully produced in the greenhouse as they have been for many years, moving production indoors can allow for more precise environmental control. Through this, we can potentially reduce crop times, increase uniformity, improve quality and reduce shrink. These seem like goals we should have for our entire production, right?

With the more expensive capital and operating costs for indoor production, high-value and high-density crops may be the best place to start. For example, you may produce 200 plugs in a flat in the same area that five to 20 finished plants can be grown. If the higher cost can be spread across a larger number of plants, the cost per plant is less.

Now to address one of the largest indoor production operational expenses: lighting. The quantity, quality and duration of light a plant receives plays a large role in the yield, development and morphology of that plant. With supplemental and sole-source lighting becoming increasingly popular and the increased efficacy and reduced cost of LEDs, growers can decide at what stage of growth to provide extra light and at what intensity. The quantity of light a plant receives can be manipulated through both intensity and photoperiod.

In this article, we will discuss intensity. If light intensities are too low, plants may become leggy, remain very small, have poor root systems or grow poorly once transplanted into their final production environment, whether that is a greenhouse or outdoors. However, if the light intensity is too high, the plants may not be using the light efficiently and you waste energy. The light may also cause leaf damage and reduce growth and plant quality.

Experimental protocol

If we provide increased inputs (such as higher light intensities during indoor production) throughout the seedling stage, can we increase growth? If so, can these more robust transplants result in increased yields at harvest? These are some of the questions we set out to answer in this study.

We grew basil because it is one of the most popular fresh culinary herbs grown in controlled environments. ‘Nufar’ seeds were sown in Grodan rock-wool cubes and placed under Fluence Ray 66 PhysioSpec Indoor LED fixtures in a walk-in growth room. The fixtures provided broad spectrum white light with light ratios (%) of 19:39:39:3 blue:green:red:far-red and target light intensities of 100, 200, 400 and 600 µmol·m^–2·s^–1 (Fig. 1). Lights were on for 16 hours to create daily light integrals (DLIs) of 6, 12, 23 or 35 mol·m^?2·d^?1. After two weeks under the different light intensity treatments, the seedlings were transplanted into deep flow technique (DFT) hydroponic systems in a common greenhouse environment. They were grown at an average daily temperature of 73 °F (23 °C) and a DLI of 14 mol·m^?2·d^?1 for three weeks after which they were harvested. With the plants growing in a common environment, we could evaluate whether the inputs at the seedling stage influenced growth, morphology and yield at harvest.

Results

At cotyledon emergence, it was visually apparent that there were differences between the light intensity treatments as seedlings germinated under 600 µmol·m^–2·s^–1 had larger cotyledons than those germinated under 100 µmol·m^–2·s^–1, however, we did not quantify this (Fig. 2). At transplant, two weeks after sowing, the fresh weight of basil seedlings grown under 600 µmol·m^–2·s^–1 was 287% greater than those grown under 100 µmol·m–2·s–1 and the leaf area was 738% greater (Fig. 3 and 4). Though this great of a difference in weight and leaf area is exciting, it is only the seedlings and is not directly an indicator of finished production yields and profits.

After three weeks of growing in the greenhouse, there were visual differences between the seedling light intensity treatments (Fig. 5). For example, the number of branches increased as indoor light intensity increased up to 400 µmol·m^–2·s^–1 with those grown under 100 µmol·m^–2·s^–1 having 2 fewer branches, than those plants grown under 400 or 600 µmol·m^–2·s^–1. The fresh weight at harvest also increased as seedling light intensity increased. For example, plants grown under 100, 200, 400 and 600 µmol·m^–2·s^–1 weighed an average of 32, 39, 54 and 58 g, respectively, at harvest. That is an 80% increase in fresh mass yield between plants grown under 100 and 600 µmol·m^–2·s^–1.

Take-home message

Although light intensities of 400 to 600 µmol·m–2·s–1 are above what most indoor facilities currently provide, we have shown that these intensities during basil seedling production can have a large impact on harvestable yield. Though results may be species dependent, we are currently conducting studies on other species to provide more complete recommendations (stay tuned for more information). Also, different production times or growing multiple seeds per cell may alter the results. We always recommend conducting your own trials before widespread adoption.

Kellie Walters is a PhD student and Roberto Lopez is assistant professor and controlled environment/floriculture extension specialist in the Department of Horticulture at Michigan State University (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, Dramm for watering supplies, and MSU AgBioResearch, MSU Graduate School, and the USDA-NIFA for funding.