Vertical Hydroponic Farm

More than 60% of the world’s population now live in urban environments. This figure is likely to grow to 80% by the year 2050. Many of us, who live in urban environments, take it for granted that we will continue to enjoy the large variety and plentiful quantities of fresh vegetables and fruits that we are able to pick up and put in our shopping carts in our local urban supermarkets, without thinking about the amounts of energy required to get them there. Also, by the year 2050, there may be another 3 billion people demanding these foods.

It is doubtful that there will be enough arable land to support these people, since we already have put 80% of all available arable land on the planet to use, and we seem to be good at reducing large amounts of such land to waste, through poor agricultural practices. The trend towards global warming won’t make the prospect for being able to grow more food any better. Global warming may make deserts out of what is now arable land, as annual rainfall patterns shift, and available fresh water supplies diminish. Current commercial agricultural methods and supply patterns also may not be sustainable.

It has been estimated that one fifth of all the fossil fuels consumed in the U.S. go into agriculture, both for producing the food (e.g., tractors, plows), synthesizing fertilizer (e.g., using hydrogen extracted from natural gas to produce nitrate fertilizers), and then transporting the food to far distant locations where they are consumed. In the U.S., we enjoy fresh produce in wintertime from Florida and California, as well as from Chile and other South American countries, who have their Summer while we slog through the ice and snow of Winter. Can we continue to enjoy these luxuries?

Another thing that many people may not realize is that the fresh produce we now consume may not even be as nutritious and safe as that which was produced in the past. Today’s commercial methods of growing and the varieties of crops grown optimize profitability by limiting losses from spoilage and transportation stress, at the expense of taste and nutrition. Our veggies simply may not be pulling as many minerals out of depleted soils as they used to, and the recent outbreaks of illness due to e-coli contamination shed doubt on our abilities to keep our food supplies safe, especially where manure is used to fertilize. An answer to the declining quality of fresh produce, and the increasing costs of growing and transporting it to urban population centers, is to produce the food right inside those urban areas, through what has been termed vertical farming. This would save energy otherwise needed to transport the food, and would make it easier to ensure the safety and quality of the food.

Vertical farming is the production of food in large multi-level urban buildings, through the use of hydroponics – or, growing plants without soil. This approach to agriculture can make much more efficient use of increasingly scarce fresh water and energy resources. Also, it could make it easier to combat insect pests and control plant diseases, because the food would be produced in a controlled environment. The nutritive quality of the produce would be ensured by closely controlling the mix of minerals and trace elements used to fertilize the plants. A large energy savings is achieved, by not having to transport the food over thousands of miles, and losses of nutritive quality are minimized by getting the food to consumers before its quality begins to decline in transportation and storage. The urban vertical farming enterprise also would provide local employment, and make local economies more self-sufficient.

The produce from vertical farming would essentially be organic, but perhaps not literally so, according to today’s understanding of that often misused terminology. Today, conventional organic food production often means that the food is produced without the use of chemical pesticides or artificial fertilizers. It’s true that vertical farming would be done without the use of chemical pesticides, but the way nutrients are provided in hydroponics growing systems may not always be considered strictly organic. That is because the nutrients used in hydroponics systems must be soluble in water.

In the natural growing cycle, plants must find the basic minerals required for growth (i.e., nitrogen, phosphorous, and potassium – the familiar N-P-K combination listed on most packages of commercial fertilizer) in soluble form in the soil. The plants can take these chemicals into their roots, only if they are dissolved in water in the soil. The plants then use these basic nutrients to grow the stems, leaves, and fruits, that we eat. Unused portions of the plants are allowed to decompose in the soil, as natural compost. Wastes from animals who consume the plants (e.g., manure) also decompose and result in natural compost that eventually is used by plants.

In organic farming, the major nutrients are made available to the plants in the form of natural or processed compost, but the plants cannot use this compost until it is sufficiently decayed to release the basic N-P-K substances into soluble form. The primary benefit of organic growing is that the N-P-K nutrients, that are provided by farmers, in the form of compost, are locked up, as complex insoluble organic molecules that cannot be easily washed away when there are heavy rains. Instead, the basic N-P-K minerals are released gradually, as the plant material decays, so there is a steady supply of required minerals for the plants over an extended period. This limits the amount of mineral nutrients that can be run off, doing damage to the environment elsewhere, by polluting streams, rivers, bays, and oceans.

In hydroponics, providing the N-P-K minerals directly, in water soluble form, does not pose a threat to the environment, because large amounts of water are not released to the environment. The unused water in hydroponics is recycled. The only water that is released to the environment is from transpiration of the plants into the atmosphere. Even this water can be recaptured and reused in the closed system of a commercial hydroponics facility. Therefore, the use of mineral fertilizers in hydroponics is entirely acceptable, from an environmental point of view.

It’s true that hydroponics systems can be run using nutrients obtained entirely from the decay of organic materials, in which case, the produce from the hydroponics system would be considered totally “organic,” but there is no real incremental benefit to either the consumer of the produce or the environment, in so doing.

Commercial scale vertical farming projects are now being planned, but none are yet in place in American cities. The first 30-story vertical farming building is now being planned for Las Vegas. Why am I talking about this now? It’s a matter of attitude. The reaction of some people to the idea of their food being produced in urban “factories” may turn them off, even though the food produced through vertical farming promises to be more nutritious, tasty, and carbon-neutral than the food they get at their local supermarket, or even at their local farm stands during the Summer. If you think seriously about the prospect of vertical farming now, you will be able to better appreciate the development of this kind of agriculture when its produce does come to a local supermarket near you.

There are some issues that I would like to see resolved before vertical farming is implemented widely. One detail that I would like to see more well-defined is the question of where the inorganic materials would come from that are needed for the hydroponics nutrients in vertical farming. Much of the nitrogen fertilizer produced for conventional agriculture today is manufactured by combining the nitrogen in the air with natural gas, which is mostly methane. This process results in a significant release of carbon into the atmosphere. However, research is now underway to provide nitrogen fertilizer through the use of biogas, from recycled farm waste. This would improve the efficiency of vertical farming and make it more carbon-neutral.

Sustainability would be a prime objective of any vertical farming enterprise. The folks who are planning these facilities certainly have this in mind, but I would like to see some more of the details and computer modeling results that must be going into this initiative. The end result should be something like what we would be doing to sustain a colony on the moon or another planet, where vertical farming is but one element of an urban system that not only grows close to 100% of its own food, but also recycles 100% of its own wastes.

Another aspect of vertical farming, that poses questions, is what conditions would exist for any domestic animals that would be raised for food in vertical farming facilities. Current plans for vertical farming also include the raising of animals for meat, like chickens, ducks, geese, fish, crustaceans (e.g., lobsters, crabs), and mollusks (e.g., squids, clams, oysters). Raising some of the higher order animals in questionable factory conditions could give rise to issues regarding their humane treatment.

Some of you may not want to wait for local production of high-quality produce through hydroponics, in large vertical farming facilities. In that case, you might want to consider raising your own food using hydroponics, right in your basement or hobby greenhouse, or even your outdoor garden. It turns out that this can be very practical. We will discuss these applications in upcoming articles.