Vertical farms are moving from concept to industrial reality.
The concept is easy: rather than using land to grow vegetables let’s use vertical structures. It is obvious that this reduces the amount of land for a given surface. There is more. The vertical “walls” on which to grow the vegetable are enclosed in a structure (a big building) making it possible to control the environment in terms of temperature, humidity, fertilisers and … bugs!
Rather than using sunlight, that would require a transparent roof and that would not be sufficient, even in with clear sky to illuminate the vertical walls, artificial illumination is used. This has the advantage of providing continuous (or regulated as needed) illumination. Furthermore the artificial light can be finely tuned to the most effective wavelength (color) to maximise the energy absorption and minimise the required power (a good portion of the Sun light spectrum goes wasted, however plants have evolved under sunlight so they have perfected their capability to use the whole sunlight spectrum. However, different plants have different “preferences” in terms of wavelength, i.e. they are more efficient under specific lighting (lettuce use only 50% of the green part of the spectrum, some plants prefer the red part, other the blue part) hence by using artificial illumination (with LED) it is possible to illuminate each plant type with their “preferred” light color (and for the right time).
Like light preferences, each type of plant requires/grows best under specific temperature and humidity level (and with very specific watering). This is clearly achievable in a closed space and moreover these conditions can be changed during the plant life cycle since a plant may need more water at a certain stage and much less at a different stage (think about rice…).
An additional benefit of growing plants in a closed controlled environment is to keep it bug free, meaning that there is not need to use pesticides to keep them bug free.
Another important plus of an industrial closed environment is that water and fertilisers can be re-used through local recycling.
As detailed above there are significant advantages in a closed environment farming, vertical farming add the important benefit of reducing the space required.
One might wonder: if there are so many advantages, how is it that we didn’t move agriculture to closed environment? The problem is cost. All these controls for temperature, water, humidity, light cost money and it is only in the last few years that technology cost has decreased to a point that makes vertical agriculture an affordable proposition.
Part of the decrease in cost derives from the full automation, in terms of control, tilling, seeding pruning and harvesting. Robots and Artificial Intelligence are the farmers in vertical agriculture.
There are now a number of companies that are experimenting with closed environment, vertical agriculture and results are very promising. The decrease in water usage is close to 99% (because of reuse, being a close system) and the efficiency measured in terms of product for square meter (of land) is 350-400 times better (this takes into consideration the loss in normal agriculture due to adverse climate events). Hypothetically, your local grocery store may become a producer of lettuce and other greens and pick them up as you ask for them at the counter.
Yet, for the foreseeable future, vertical farming is not going to replace normal “horizontal” farming, it will flank it, most likely delivering very “fresh” produce at a slightly higher cost. Normal farming, at the same time, will keep improving in effectiveness, using robots and AI as well – watch the clip, at the same time decreasing environmental impact. For an example of ingenuity to minimise environmental impact by decreasing the amount of pesticide take a look at Bee Vectoring Technology: they have created an “ecosystem” to spread pesticide using bumblebees. They provide special hives where bees get in contact at the exit gate with a fungus that sticks to their fur and is then released on the plant as they forage. The fungus is absorbed by the plant and creates a sort of immunity protecting the plant from several diseases.