As many of you, I recently read the thought-provoking article Why Growing Vegetables in High-Rises Is Wrong on So Many Levels by Dr. Stan Cox of The Land Institute in Salina, Kansas.

Dr. Cox writing is full interesting argumentations and while I agree on some of them, there are some issues that left me a little puzzled. Since I’m a very curious guy, I just have some questions for him (if he will ever read this article).

Stan Cox:

Unless I misunderstand the meaning of feasibility, Dr. Cox may have used the wrong word.
According to Toyoki Kozai’s paper (cited by Dr. Cox himself), only in Japan there were over 130 Plant Factories with Artificial Light (PFAL) by the end of 2012. Many more have been established all around the world. If they were not feasible, how could they work?

And Dr. Kozai conclusions:

Isn’t this in contradiction with the fact that they are “not feasible”?

But let’s not focus on single words meaning, because in the rest of the article Dr. Cox states clearly what are his concerns. The main one being the fact that Vertical Gardens/Farms are very energy-hungry, especially for lighting.

In Dr. Cox words:

Nobody disputes that VFs consume a lot of energy, but I’m curious to understand where the 1,200 kWh estimation come from, since Dr. Kozai articles mention that “PAR energy consumed to produce one kg of dry matter is 740 (= 20.0/0.027) MJ/kg or 205 (= 740/3.6) kWh.”
How was 1,200 kWh calculated?

I would also like to understand how he calculated the following figure:

Could somebody please shed some light over this 1.3 billion tons number?

Then, he writes about another issue, that VF produces will not be for every budget. Citing another study:

And the very same GIZ paper concludes also:

Sure that 3.50 €/kg to 6.00 €/kg is maybe not a popular price, but it’s not so far away from current vegetable costs. We are not talking about orders of magnitude of difference.
Why is Dr. Cox so critical over production costs? In the long term, advancing in technology will improve the yields and drive down the production costs. It always happens with new technology/products introduced to the market. Just think about smartphones, TVs, cars, and just almost anything else.

It is clear that Dr . Cox is very critical about vertical farms with artificial lighting and very categorical about their the non-feasibility.
His article left me with doubts, but he is right in pointing out some issues about VF. Indoor farming is very power-hungry. Costs are not yet on par with current growing methods. VF is not applicable in all situations and is not the solution to ALL the problems.

But just saying that VF is not feasible, stop thinking about it, forget about it, it’s a little too limiting. Dismissing the whole VF concept because there are some issues, is throwing the baby out with the bathwater. Yes, there are issues, and it’s important that we acknowledge them, and then we discuss and explore the possible solutions.

We need also to give a more comprehensive look at the problem.
If on one side we have the high energy consumption of lights (and temperature regulation), on the other hand vertical farms save on energy used for other agriculture operations. Just think about soil preparation, seeding, irrigation, fertilization, chemicals distribution, transportation, processing, packaging, refrigeration… all these operations in some way have an impact on the environment.

What we need is a Life Cycle Assessment (LCA) comparing VF and traditional agriculture and including the whole cycle of the plant, from cradle to table.
It is important to consider not only the energy and environmental impact, but also the other advantages of VF, such as the drastic reduction of pesticides and herbicides, healthier food, better use of water resources and increased food security.

Only with complete analyses of different situations we could assess if, when and where a VF is “feasible”.

What is your opinion? If you have links to good LCA analysis of VF compared to traditional agriculture, leave them in the comments.