3. Employ Good Barrier Design for Plant Protection
Better Safe Than Sorry
Food security and safety issues have to be dealt with as two sides of the same coin and are the primary concerns of the vertical-farm management team. Both have risen to the top of the list that forms the basis for a national food safety program coauthored by the USDA and the Department of Homeland Security. Outdoor farming represents an open-ended, no-holds-barred battle to the death between the crops we plant and those things that would consume them before they reach our plates. Outdoor control strategies, for the most part, consist of programs designed to limit the spread of a given insect pest or disease by the application of pesticides or herbicides or by culling only the affected portion of the crop, all the way up to destroying the entire year’s planting. Inside, things will be quite different and much more controllable. The exclusion of unwanted visitors by applying positive pressure to the building housing the crops and nursery buildings will be the first step. Designing double-lock-entry doorways will allow for an additional level of protection against insects and microbes. Requiring all personnel to change into sterilized, disposable safety uniforms, shoe, and hair coverings, and to shower before changing clothes, will minimize the risk of crop loss due to “hitchhikers” on items such as shoes. Because the vertical farm will not need fertilizers, the risk from contaminating plants with human pathogens will be all but eliminated. This must be coupled with an initial—followed by an annual—routine series of laboratory tests for all vertical-farm workers designed to detect carriers of salmonella, giardia, cyclospora, and the like. (See the table.) Animal pathogens such as E. coli 0157:H7 will have no chance of contaminating the produce of the vertical farm, since no large herbivores will be housed anywhere in or near the complex. If a security breach does occur in the vertical farm resulting in contamination of the crop, then destroying the entire crop can be dealt with the very next day. Once the security leak has been identified and fixed, the vertical farm could resume full production within a reasonable length of time. On the outside, the farmer must wait until the following spring to begin again, and often with the same disastrous results. Frustration is indeed the mantra of the outdoor farmer.
Faecally Transmitted Infections
VIRUSES
Rotavirus
Hepatitis A
Hepatitis E
Polio virus
Norovirus
Adenovirus
Astrovirus
BACTERIA
Salmonella typhi
Shigella
Vibrio cholerae
E. coli strain 0157:H7
Camplyobacter jujuni
Helicobacter pylori
Clostridium difficile
FUNGAL
PROTOZOA
Entameba histolytica
Giardia lamblia
Blastocystis hominus
Cryptosporidium parvum
Cyclospora cayetanensis
Endolimax nana
HELMINTHS
Hookworm
Trichuris trichiura
Ascaris lumbricoides
Fasciola hepatica
Schistosoma mansoni
Schistosoma japonicum
Heterophyes heterophyes
Ophistorchus viviarini
Paragonimus westermani
Clonorchis sinensis
One additional idea for early detection of invading microbes should be mentioned, although it is not quite off the drawing board yet. Imagine the deployment of a genetically engineered nonedible plant species (arabidopsis comes to mind as a prime candidate for this kind of job) to monitor for the presence of a variety of plant pathogens using a molecular biological approach. The plant could be modified with a reporter molecule such as fluorescent green protein that has been stitched together with a snippet of DNA from the offending microbe. The “canary in the coal miner’s cage” plants would be interspersed among the crops. Simply by turning off the lights at night and turning on the UV light, one could tell if any individual plant has encountered the pathogen, since it would glow green. Then culling that area would be simple and could save an entire floor’s worth of crop plants. Just a thought.
4. Maximize the Amount of Space Devoted to Growing Crops
How to configure each floor of the vertical farm will depend solely on the crops selected. As the hydroponics industry matures, many different growing modalities will arise to meet the challenge of maximizing the yield for all the crops inside. Today, there is enough experience with hydroponic technologies to offer the bare-bones essentials of what is available and what we might expect to see over the next few years given the current rate of progress. Many plants are “comfortable” growing in the traditional hydroponic piping complete with holes. The plants are spaced at a similar distance apart, as one might see on a traditional soil-based farm. Tomatoes, lettuce, spinach, radicchio, green beans, peppers, zucchini, cucumbers, cantaloupes, and many others fall into that category. Grains are best grown in sheets of inert material similar in consistency to a spongy fiberglass air conditioner filter. One new approach for growing aeroponic grains uses a Dacron-based clothlike sheet as a matrix for the roots that the seeds are spread onto and then germinated. Nutrients are sprayed on the sheet from below. Lighting then becomes the biggest challenge, especially when growing several layers of the same crop in the grow room. The hydro-stacker employs a form of drip irrigation for growing potted plants such as strawberries, eggplant, and avocado. Even corn can be grown hydroponically in large tubs, usually with six plants per tub. Each plant yields around three ears per plant, and a crop matures every eight to ten weeks, allowing for at least five crops per year. If one wanted to, the system for growing could be reconfigured onto a conveyer belt–like hydroponic system. Producing corn indoors in the vertical farm actually could become quite profitable and allow for the reclaiming of many acres of land at the same time.
Piping can be made from a wide variety of materials, but most of today’s hydroponic/aeroponic equipment is made of some variety of plastic. Polyvinyl chloride (PVC) plastic is readily available and is the most commonly employed material for constructing hydroponic grow systems. Leaching of toxic phthalates from PVC into the nutrient solution is a concern and can be minimized by first treating the PVC with a dilute sulfide solution. This treatment crosslinks the plastic, trapping the phthalates permanently, and eliminates any health risk that might be associated with leaching. Some people would object to the use of any plastic, however, due to environmental considerations, mostly what happens to the plastic after it’s discarded. The accumulation of all varieties of plastics in landfills and aquatic environments such as the open ocean is absolutely appalling and unacceptable. This kind of pollution is now totally preventable by instituting some form of environmentally friendly incineration. I would agree that burning any plastic product in a conventional (i.e., low-tech) incinerator produces noxious compounds that have serious health risks associated with them, but this situation can easily be avoided by vaporizing PVC and other plastic polymer products in a plasma arc gasification system. If we really get clever, perhaps we can find a use for various diameters of hollow bamboo and forget about plastics altogether. It is one of the fastest-growing plants, it’s strong, it does not rot when kept wet, and it can be harvested to match any desired diameter of piping.
Undoubtedly, as vertical farming becomes perfected over the next few years, innovation at the level of configuring the grow space for all major crops will win the day. Until then, I can only offer this meager list of suggested modes to address the most important issue of maximizing the yield.
Cradle to Crop
Once the construction of the vertical farm complex is complete, the next step will be to purchase and receive starting materials (i.e., seeds). Where to get seeds for any crop is not a trivial issue, since there are many varieties of each cultivar to choose from. Fortunately, there are organizations specializing in supplying seeds (e.g., Siegers Seed Company, Florida Foundation Seed Produc
ers, Inc., Good Seed Company, Neseed) that have served the commercial outdoor and hydroponics communities well, and their names can be found in publications that cover the greenhouse industry. One publication that I have found particularly helpful and informative is Practical Hydroponics & Green houses. The Food and Agriculture Organization is another superb resource for this kind of information, as is the USDA. Some seed producers have genetically engineered their own crops, particularly corn and soybeans, to resist things such as drought and herbicides. Monsanto is one of those corporations and has a strict policy about the use and production of its seeds (see the film Food, Inc). In my view, restricting the use of seeds for any purpose limits their application to large commercial outdoor establishments where adverse weather and invasion from weeds is a constant problem. The whole rationale behind the vertical farm is to avoid these problems to begin with.
The seeds must first be surface decontaminated, then sent to the diagnostic laboratory for testing for the presence of microbial pathogens that might be commandeering them as their Trojan horse. Once certified disease-free, the seeds will be sent to the nursery for quality-control testing and germination. The nursery will be a separate facility from receiving, as the nursery is the first chance any pathogens might have of directly contaminating the inside of the vertical farm. Since the germinated seedlings will eventually have to enter the vertical farm, security must also be maintained in this building. The nursery and vertical farm will most likely be connected by a maximum-security pressurized lock system. Seeds will first be evaluated for their ability to germinate and grow. All plant crops will originate in the nursery as germinated seedlings, and once germinated they will be tested again for any pathogens that might have slipped through the first screening. The infant crops will be transferred to the vertical farm and situated into their hydroponic/aeroponic environment. All crops will be constantly monitored by remote sensing systems for growth and nutrient conditions. Much of the work in the nursery will be labor-intensive, creating many new job opportunities for those with a green thumb.
Cool, Clear Water
Water for the vertical farm will be used in hydroponic and aeroponic growing situations, and for the workers for their showers and drinking water. It could come from several sources, depending upon the geographic location and the ability of the urban community to access grey water for reuse. The highest-quality water should be used whenever possible. Usually this means drilling a well or obtaining water from a river, lake, or reservoir that is then filtered before being applied to crops. The obvious advantage of controlled-environment agriculture is the fact that it is a “closed loop” system, thereby allowing for the capture of water vapor derived from transpiration by employing dehumidification devices on each floor. This represents a highly efficient system of water use for farming compared to the traditional mode of outdoor soil-based agricultural irrigation schemes. In the closed-loop system, as mentioned earlier, hydroponics uses some 70 percent less water than conventional farming, while aeroponics uses 70 percent less water than hydroponics. In either case, it is a substantial improvement, and for areas of the world in which water is already in short supply, switching to vertical farming is the only reasonable approach to allow more water to be made available for drinking purposes. As also pointed out earlier, no runoff occurs in the vertical-farm model. If implemented on a large scale, vertical farming would have the possibility of eliminating ocean pollution from agricultural runoff. This has to happen if the productivity of the world’s estuaries is to be restored.
What’s for Dinner?
The question often arises as to which crops can be grown indoors. The answer is a surprising: “Anything you want.” All one has to do for proof is visit any well-maintained botanical garden, for example, Kew Royal Botanic Gardens in London, the Bronx Botanical Gardens in New York, or the Missouri Botanical Garden in Saint Louis. Nearly every kind of exotic plant can be found inside these wonderful facilities. The New York Botanical Gardens, for instance, houses and cares for the world’s largest (and, it might be noted, smelliest) flower, Rafflesia arnoldii, which is quite rare and grows in splendid isolation in the dense tropical forests of Indonesia. Fortunately, it rarely blooms, or the whole place would always stink of rotting flesh. If horticulturists can manage to grow that oddity, then anything is possible. As for the edible plants, one needs to consider several things before choosing which ones to grow. First, there are economic considerations. Is it worth the effort? Can farmers sell out the crop each and every time it’s harvested, and at a profit? Can it be presold to commercial buyers? If so, all the better if profit is the main driving force behind that particular vertical farm. So far, a few popular vegetables have been grown successfully for profit. These include tomatoes, lettuce, spinach, zucchini, green peppers, and green beans. The strawberry has also been a star for the indoor farmer. Hardly any of these crops would qualify for addressing the needs of a hungry world, however. Essential crops such as wheat, barley, millet, rice, and potatoes would be more appropriate. The answer as to whether or not we can grow these crops indoors is still yes. All of them have been grown hydroponically. If their successful production means that a country that had to import nearly all its produce can now, within its own borders, supply its own population with an essential healthy diet, then profitability takes a backseat to need. Government-sponsored food programs may become the determining economic factor in the form of incentives and subsidies that enable the vertical farm to survive and even thrive, producing crops that in a free-flowing market economy would ordinarily fail to generate enough income to make them worthwhile.
An online resource that is very helpful in all aspects of hydroponic farming is the National Sustainable Agriculture Information Service (http://www.attra.org/). As one can see, the choices of crops that could be produced in the vertical farm far exceeds any consumer demand, regardless of the cuisine, with the exception, of course, of the meats derived from livestock.
Dangling Modifiers
Undoubtedly there are other topics that one should take into consideration when designing, building, and then operating the vertical farm, but I think most of the important ones that deal with its “nuts and bolts” and general systems have now been laid down, albeit in a highly truncated executive summary form. More detail regarding any of these areas would require sitting down with a team of experts in a wide variety of fields related to architecture, agronomy, engineering, and the like and brainstorming until a blue-print for the prototype vertical farm emerged. I don’t claim to have enough expertise or insight to offer any higher level of description of any of the topics covered in this chapter, so I am afraid we will all have to wait until such a team is assembled and given their marching orders to find out what happens next. There is one missing area I can address, however, and that is who will work in the vertical farms, and who will benefit most from their creation.
chapter 7
The Vertical Farm: Social Benefits
Our only security is our ability to change.
—JOHN LILLY
The vertical farm is the keystone enterprise for establishing an urban-based ecosystem. Without food production, no city can emulate the virtues of a functional, intact ecosystem: Bioproductivity is key for both. It is the defining mechanism for energy management for all living organisms. Yet, if the city can supply itself with at least 50–80 percent of its agricultural needs, then lots of other sustainable activities become achievable, allowing its citizens to capture and reuse the energy of their own metabolic by-products and reclaim the grey water. Establishing vertical farming on a large scale would be the start to a complete remake of urban behavior centered around the concept of doing no harm to the environment. Ultimately, it is about creating a healthier lifestyle for anyone living anywhere in the city, making the built environment an ideal place to raise children, and about improving the overall environment of the planet.
Uncontrolled Growth is the Philosophy of the Cancer Cell
Architects an
d city planners are fond of referring to cities as “living organisms”; cities have a soul, a life of their own, a unique personality. They lean toward describing metropolises in ethereal, romantic, abstract terms, waxing creatively and often misusing basic English in the process. I have heard some even go so far as to state that the city is a new form of “organic” superbeing, evolving out of the collective energy of all those who have had a hand in shaping its past, present, and future. If that is true, then despite all the nice descriptors, hype, metaphors, and genuine cultural advantages of living in one, in reality the city has assumed the role of a monstrous parasite when viewed from an ecological perspective. It sucks up prodigious quantities of the earth’s raw materials, gulping down the nutritious parts in a single, noisy, pollution-producing swallow, then spews, sprays, flings out waste of all kinds onto its own doorstep and well beyond. Seen through the eyes of the natural world, a modern city is a twisted amalgam of concrete, steel, and glass crammed full of two-legged, very aggressive life forms; a place to be avoided at all costs, save, of course, for those animals—rats, mice, sparrows, pigeons, squirrels, cockroaches—opportunistic enough to take advantage of the absence of large predator species. In fact, there is a highly successful urban ecosystem, sans humans, filled with secretive denizens of the night that consume piles of unused biomass in the form of curbside garbage. It’s estimated, for example, that New York City supports some ten rats per person. That’s 80 million rodents, and what do you suppose they eat? Not garbage; it’s too risky. They consume a diet rich in cockroaches, insects that gladly take chances to gain access to the restaurant wastes generated each day by the more than twenty-eight thousand food establishments within the city limits. Surely we can find a better use for that organic refuse than to enable and energize the roach/rat ecosystem.
Regardless of location, the city has grown helter-skelter, and its insatiable appetite and out-of-control metabolism produces nothing more useful than lethal bubbles of heat and contaminated air and water laced with the by-products of its mechanized infrastructure. “Metropolis” has become synonymous with “consumption.” None of this negative behavior was planned, yet urbanization over the last hundred years turns out to be a thousand times more destructive than all wars put together, both in the scope of the planetary damage it has created, the number of human deaths caused by unhealthy living conditions, and its penchant for continuing to cause even more disruption of the natural world on an ever-increasing scale, as new methods for construction are established. Godzilla is a mere toddler’s hand puppet compared to the way the city itself has risen up into the surrounding landscape and crushed it flat with its big foot of progress. Atlanta, Georgia, is a case study that NASA features on its Web site, which shows how that city grew over a twenty-year period as documented by LandSat satellite imagery. Older case studies include those governed by the Aztecs, Mayans, Romans, and other failed cultures, eloquently described by Jared Diamond in his book Collapse. Granted, we have come a long way compared to the ancient Romans, who routinely discarded their garbage right out their windows onto the streets of the Eternal City, but in many cases, our “garbage” still comes back to haunt us just the same. Landfills, brown fields, rodent-infested abandoned city lots, nonpoint source runoff, coal-burning power stations, refineries of all kinds, not to mention all forms of vehicular traffic, add insult to an already injured biosphere. Encroachment is what we do, even though every time we extend the urban boundary, there is usually a heavy health risk associated with it. This is especially true in the tropics. For example, the building of the Transamazonian highway resulted in construction workers becoming infected with several new varieties of disfiguring dermal leishmaniasis. Yellow fever became more prevalent along its course, and countless species of wildlife became extinct due to extensive deforestation.
The Vertical Farm Page 14