Innovations in Indoor Farming

large commercial greenhouse growing leafy greens

Indoor agriculture is no longer just for the greenhouse…”farmland” is now on a rooftop, contained in a repurposed shipping container, and made vertical in a multi-level warehouse. Because of new technologies and consumer demand, this fast-growing industry will play an important role in our food supply chain.

Local and Fresh

As consumers, we are looking for transparency in the food supply chain. Where is our food coming from? Is it safe? How was it grown? New farming technologies help answer that for fresh greens, herbs, and some veggies, which can be grown almost anywhere.  For instance, 90% of the salad greens we eat are produced in California and Arizona. However, companies like Gotham Greens and BrightFarms let urban dwellers buy locally-grown greens as soon as 24 hours after harvest. That certainly has a lot of appeal! It is more nutritious, tastes better, and can be cheaper as it cuts out much of the transportation costs.

graphic adapted from

Making an Environmental Impact

Amid projections that the world’s population will grow from today’s 7.5 billion to 9.6 billion by 2050, the environmental pressures on our water, soil, and land are increasing. Alternative forms of agriculture offer another way to alleviate some of these stresses, especially in urban areas where adequate farmland is limited. Creating “farmland” from unused space is in the future. High-tech growers use hydroponics, aeroponics, and aquaponics methods to grow leafy greens and vegetables. Large metropolitan cities, like Chicago and New York, and cold regions with limited growing seasons, like Northern Minnesota and Wyoming, have the ability to grow local crops all year round via indoor “farmland”.

A recent report from Cornell University and several other organizations found that revenue could be up to 4000x higher in indoor farming systems because of the ability for multiple year-round harvests, higher yield per acre and higher retail pricing (a premium for local or organic). For example, lettuce grown by a conventional farmer will have 4-5 harvests each year, whereas an indoor farmer can have as many as 18 harvests per year. According to the USDA, the average yield for an outdoor farmer was about 30,000 pounds per acre and indoor farmers reported an average of 340,000 pounds per acre.

Head lettuce growing vertically hydroponically in a Freight Farm. Source: Freight Farm

In addition to this increase in productivity, indoor farming practices also significantly reduce the environmental impact compared to that of a traditional farm. Indoor farms reduce greenhouse gas emissions, minimize waste, and recycle water to produce the best, most sustainable crop. On average, they use 85% less water, 80% less fertilizer, 70% less land than conventional farming. In addition, these companies utilize sophisticated technologies to improve facility construction, LED lighting, water circulation, plant nutrient delivery, and environmental controls.

Meet the ’Ponics: Hydro, Aero, and Aqua

Because of these advancements, hydroponic, aeroponic, and aquaponic farming systems are quickly moving from the realm of “experimental technology” to verified commercial applications. Researchers and growers alike have turned indoor systems into working models of sustainable food production. According to the report “Vertical Farming Market”, the market is estimated to reach $3.88 billion by 2020, at a compounded annual growth rate of 30.7% between 2015 and 2020. The factors driving the vertical farming market include the need for high-quality food without pesticides, less dependency on weather, produce availability for an increasingly urban population, and the need for year-round production.


Hydroponic farming is a method of growing plants in water, without soil. Plants are fed minerals and nutrients directly in the water where the roots grow.  This is particularly good for greens and vegetables.

Simple hydroponics: Nutrients are added to a tank of water to create a nutrient reservoir which is kept separate from the plants. The water is then pumped up a network of tubes, and released to the plants.
image source: hydroponicsgrower

Hydroponically grown lettuce. Image source: citycrop



Aeroponics is a subset of hydroponics, but instead of the minerals and nutrients circulating within the root chamber, it is misted to the roots at regular intervals. NASA began studying the feasibility of plants grown aeroponically in 1990 as a way to have crew members grow their own food while circling Earth.

source: Aerofarms


Aquaponics works on the basic idea of a closed production system. Farmed fish produce waste that is the perfect fertilizer for plants. Plants utilize the waste and filter the water to give the fish a clean habitat. The Aztecs grew a wide variety of crops such as maize, squash, and other plants in tandem with rearing fish for food. And as early as the 6th century, Chinese farmers reared ducks, finfish, and catfish in a symbiotic cycle: the finfish were fed with duck droppings, the catfish were fed with the finfish waste, and any “leftover food” was used to supply the nutrients to the rice in the paddy fields.

image source:

Where Do These ’Ponics Live?

Freight Farms is bringing farming to the city. image source: FreightFarms

…shipping containers

Freight Farms, based in Boston, uses the “Leafy Green Machine” (LGM), to harvest year-round in any region of the U.S. The LGM is a pre-assembled hydroponic farm inside an up-cycled freight container. The hydroponic system automatically delivers precise water and nutrients for maximum crop development and uses LED lights optimized for each stage of the growing cycle. Vertical growing towers maximize space and create a high-density growing environment.

Alaska’s Vertical Harvest Hydroponics also uses repurposed shipping containers to grow fresh greens in the most inhospitable environments. What makes shipping containers unique is that they are transportable, can fit in small spaces, and can withstand extreme temperatures without affecting the crop. The modular tower system from ZipFarms is adaptable to a hydroponic or aquaponic system and can be utilized by commercial growers and backyard growers alike.

…rooftops and greenhouses

Gotham Greens has built and operated over 170,000 square feet of technologically-advanced, urban rooftop greenhouses across four facilities in New York City and Chicago. They have partnered with Whole Foods and have built their greenhouses in strategic urban areas to distribute fresh produce within 24 hours of picking to retail operations. And their annual produce production? 200,000 pounds! Equivalent to 100 acres of conventional field farming.

Gotham Greens greenhouses in Greenpoint, Brooklyn

Bright Farms and Mighty Vine are further examples of high tech agriculture companies innovating and developing ways to grow indoors. BrightFarms finances, designs, and operates greenhouse farms at or near supermarkets, cutting time, distance, and cost from the produce supply chain. They operate three on-the-ground greenhouses in the greater Philadelphia, Washington D.C. and Chicago metro areas. MightyVine, based in Chicago, grows tomatoes all year round in sophisticated greenhouses using vertical growing methods, which produce 900,000 lbs of tomatoes per month in peak season!

…in a warehouse

New Jersey-based vertical farming company, AeroFarms approaches food production with aeroponics to mist the roots of greens with nutrients, water, and oxygen. The company asserts that its closed loop aeroponic system uses 95% less water than field farming, 40% less than hydroponics, and zero pesticides. Their growing technology is very modular and can be adapted to different repurposed industrial spaces. And they harvest up to 2 million pounds per year with this system.


While no one expects that urban agriculture will never replace traditional farming, it relieves some of the pressure off rural land and satisfies some of the demands for local and sustainable agriculture.

Additionally, Green Sense Farms, from Indiana, harvests 26 times a year and since it has teamed up with grocery stores, restaurants, caterers and produce companies.

How Safe is Our Food?

fresh fruit at farmers market

Contributing writers Susan Leaman and Diane Wetherington have extensive experience and knowledge in the food industry. Susan works with companies and associations to develop solutions that address produce-related food safety issues; and Diane is CEO of iDecisionSciences, LLC, a provider of specialty crop consulting services, and iFoodDS, Inc., a software solutions provider for the food industry.

One of the most important underlying considerations to the food industry supply chain is food safety. As consumers, we are familiar with the more popular food recalls such as Listeria monocytogenes, pathogenic E. coli, and Salmonella—but here is a look at the bigger picture. Industry experts Susan Leaman and Diane Wetherington provide an overview of what food safety encompasses in the food supply chain.

How does food become contaminated?

Food is considered contaminated – or “adulterated” in official jargon – when something potentially harmful is found in or added to it. Food contaminants are categorized in three ways: chemical, physical, or biological.

Chemical contaminants, such as heavy metals (e.g., cadmium, arsenic, lead), may occur naturally in the soil or as a component of an agricultural chemical and are taken up by the plant as it grows. Chemical contaminants may also be deposited in the soil and/or plants from the surrounding environment (i.e., from a nearby landfill or the smokestack of a nearby factory).

@Scott Hilburn

Foreign material, such as metal fragments, stones, rodents, bugs, hair, etc. in a finished food product is considered a physical contaminant and can contaminate the food crop during harvest and transportation or when it is in the processing or manufacturing facility.

Biological contamination is what we most often hear or read about in the news. The most common biological contaminants are microorganisms – food safety professionals call them human pathogens and the rest of us commonly call them “germs”. Most of these germs are undetectable by smell or any visible signs caused by spoilage that may make the food inedible. You wouldn’t choose to eat a mushy apple over a crisp one, for example. But this does not necessarily mean the food is unsafe. However, some microorganisms such as parasites, viruses, and bacteria when consumed in a large enough amount, can make you sick. A sickness caused by eating food contaminated with parasites, viruses, and pathogenic bacteria is called foodborne illness. These germs can be introduced into food at any point from production through food preparation and delivery. For example, wildlife may enter a field and defecate on the crops, manure can be improperly composted, trucks may have contaminated cargo areas, and workers preparing food may have unclean hands.

Any food that does not receive a treatment to kill harmful germs is more susceptible to contamination. Unpeeled, raw, or undercooked foods are most susceptible to germs due to inappropriate handling of raw food and cross-contamination onto cutting boards, knives, and kitchen counters. Cooking or pasteurizing food for a specific amount of time at a threshold temperature kills human pathogens. Proper kitchen safety is also important.

Which foods have been associated with foodborne illness outbreaks?

In 2013, the Center for Disease Control and Prevention (CDC) published an assessment of the foodborne illness outbreaks that occurred in the U.S. between 1998 and 2008 (Painter, 2013). The agency evaluated the outbreak-related data by the type of hazard (bacterial, chemical, parasitic, and viral) and food deemed responsible based on the outbreak investigation, and found that 34.2% were attributed to contaminated vegetables, 13.8% to dairy products, 12.2% to meat, and 11.7% to fruits and nuts. The majority of foodborne illness outbreaks were caused by viruses (57%) and bacteria (38%) while parasites and chemicals caused 2% and 3%, respectively.

Foods Associated with Foodborne Illness:

  • Raw foods of animal origin, that is, raw meat and poultry, raw eggs, unpasteurized milk, and raw shellfish are the most likely to be contaminated.
  • Fruits and vegetables can also be contaminated with animal waste when manure is used to fertilize produce in the field, or unclean water is used for washing the produce.
  • Raw sprouts are particularly concerning because the conditions under which they are sprouted are ideal for growing microbes.
  • Unpasteurized fruit juices or cider can also be contaminated if there are pathogens on the fruit that is used to make it.
  • Any food item that is touched by a person who is ill with vomiting or diarrhea, or who has recently had such an illness, can become contaminated. When these food items are not subsequently cooked (e.g., salads, cut fruit) they can pass the illness to other people.

For the curious, the CDC’s foodborne illness outbreak online database (FOOD tool) is available here, and the U.S. Food and Drug Administration (FDA) also publishes a record of foods recalled due to contamination.

So are foodborne illness outbreaks really increasing in frequency?

Not necessarily. We are more aware of food recalls because of reporting systems, testing programs, and the ability to detect pathogens.

Communicating foodborne illnesses through reporting systems that link health care providers and public health agencies have greatly improved since the mid-1990s.  Surveillance of the food supply by government agencies and product testing by food manufacturers has also increased, leading to more product recalls. Finally, technological advancements have made it possible to detect pathogens in lower amounts.

What is the food industry doing to prevent food contamination?

There are various stakeholders that play a role in ensuring the safety of our food supply. Although you may occasionally read the news of people who knowingly put contaminated food into commerce, by far, the vast majority of those involved in producing our food are very concerned about the safety of consumers – after all, their family and friends eat the food, too.


At the farm level, numerous food safety guidelines or good agricultural practices (GAPs) have been established by industry with the help of trade associations, government agencies, and other food safety experts. GAPs address the use of water, soil amendments, tools, and equipment; the hygiene of field personnel; what to do if a field floods or if animal feces are found in the field during harvest; and many other circumstances that compromise the safety of the crop. Some of these guidelines are the basis for voluntary food safety programs; some are enforced under mandatory programs (e.g., California Cantaloupe Safety Standards) while still others are mandatory after a company voluntarily joins the program (e.g., Arizona and California Leafy Green Handler Marketing Agreements).

Food Service, Retailers, and Food Packing/Processing

Companies that pack, process, or manufacture foods implement various practices, processes, and procedures have been required by law to implement good manufacturing practices (GMPs). Although the rules have been updated over the years, current GMPs cover facility design, conditions of the grounds around facilities, cleaning and sanitation of facilities and equipment, pest control, worker hygiene, workflow, and other potential sources of contamination.

Non-profit Organizations and Third-Party Auditors

There are also various international non-profit organizations that maintain food safety schemes established by working groups and committees of industry, government, and academic food safety professionals. The Global Food Safety Initiative is one of these international organizations that certifies food safety schemes against a set of industry-derived standards. Farms and food manufacturing companies subscribe to these schemes, often at the behest of their customers, and third-party auditing companies evaluate and score the manufacturer’s performance against the scheme’s standards.

Since 2009, food manufacturing and processing facilities are required to be registered with the FDA and report when any microbial test results are positive. When microbial testing indicates that food is contaminated/adulterated with human pathogensa recall is issued. In addition to food companies self-reporting contamination, the FDA routinely inspects food manufacturing/processing facilities, and if they find conditions that compromise the safety of the food (i.e., unsanitary conditions), the agency issues warning letters that are made public. Facilities then have an allotted amount of time to address the issues, and if they fail to do so, they can ultimately be shut down. This is exactly what happened in 2012 to a food manufacturing company that made organic nut-butters for Trader Joe’s. Based on numerous GMP violations, the company’s own product testing records, and the FDA’s microbial test results, the agency shut down operations after the facility failed to properly address the violations.

The Food Safety Modernization Act

In 2011, the Food Safety Modernization Act (FSMA) became law. The FSMA upgraded existing laws governing food manufacturers and processors, and more significantly, for the first time, included oversight of food production on farms. Prior to the FSMA, farms were not inspected by the FDA or the U.S. Department of Agriculture (USDA). Additionally, aside from a foodborne illness outbreak, government regulators were not authorized to inspect a farm. This means FDA regulators were unable to investigate the facilities, fields, coolers, food storage areas, etc., and to question the operators about their practices.

As part of FSMA, the FDA wanted to better understand how food is grown for every commodity. It was important for them not to make the rules so onerous that farmers would go out of business. Thus, the FDA visited farms, held public meetings to hear farmers’ and consumers’ concerns, and revised the rules they proposed based on the feedback from industry and the public. By 2018, the FDA will begin conducting both announced and unannounced inspections of farms. They will begin inspecting large farms (produce sales > $500,000) with inspections of smaller farms phased-in over the next five years. Farms making less than $25,000 are excluded from FDA inspection, and other small farms will have less stringent requirements if their food sales are less than $500,000, and 50% of their crop is sold directly to consumers or retail food establishments/restaurants.

In 2011, the Food Safety Modernization Act (FSMA) became law. The FSMA upgraded existing laws governing food manufacturers and processors, and more significantly, for the first time, included oversight of food production on farms.

Under FSMA, food manufacturers and processors will also be required to establish and implement a food safety plan and a supply-chain program that addresses how to reduce and minimize the potential for food to become contaminated from biological, chemical, or physical hazards and what to do when contamination occurs (i.e., corrective action procedures and product recall plans). As part of the food safety plans, food manufacturers and processors will need to verify that the implemented practices and procedures to control hazards and prevent contamination are indeed working. Verification procedures may involve testing raw or finished product and/or food production areas and equipment for microorganisms. And just like the new rules and standards for farms, announced and unannounced inspections of large food manufacturers and processors will begin next year with compliance deadlines phased in over the next several years for smaller companies.

Joining the FDA in overseeing the safety of the nation’s food supply on the federal level is the USDA and the CDC. The USDA’s Food Safety and Inspection Service (FSIS) is the public health agency responsible for the safety of meat, poultry and egg products. USDA inspectors are on-site at meat production facilities to ensure that best practices are being implemented to reduce the potential for contamination. The CDC is the federal public health agency in charge of identifying and tracking foodborne illness outbreaks in the U.S. and assists other countries in doing so as well. Other government agencies that are involved in food safety are state and local health department and state agricultural departments.

So what do you do if you think you had a case of foodborne illness?

The CDC collaborates with the FDA and USDA in foodborne illness outbreak investigations, helping to identify what caused the outbreak and alerting the public when a source is identified.


As illustrated in the timelines, it all starts when sick individuals go to the hospital or their doctor or contact their local health departments to report illnesses that they believe occurred from consuming contaminated food. These reports, often accompanied by microbiological testing, are then relayed to state health departments and the CDC. The CDC collaborates with the FDA and USDA in foodborne illness outbreak investigations, helping to identify what caused the outbreak and alerting the public when a source is identified. Methods for connecting foodborne illness cases to one another and the food source have vastly improved over the past decade resulting in increased identification of foodborne illness outbreaks. This phenomenon, not higher risk of illness, is the primary reason you are hearing and reading more about foodborne illness outbreaks.