Historically, the cheapest way to "grow" farmland has been to make marginal land more productive.
And of methods for doing that, irrigation is the most effective. This speaks directly to Liebig's Law of the Minimum, which states that whatever factor is most critical in limiting plant productivity is the one whose adjustment will have the greatest impact on productivity. For plants, water is a cheap addition, it's frequently the critical missing factor in increasing land productivity, and will literally take you from 0 to 100% alone.
By this reasoning, "vertical farming" is taking land as the limiting factor and literally requires building more land, substrate, water, sunlight, and nutrients in order to increase areal productivity. This is close to a maximally expensive expansion option. To date, vertical farming has been utilised only on very high-value crops, or those for which freshness is at an absolute premium. (Fresh crops can be moved across and between continents in days or hours, though quite often a 14-day transport with refrigeration retains freshness.)
For bulk cereal staples, overall land area remains the principle limiting factor, with sunlight, water, topsoil, fertiliser, and pest control as principle inputs. Weather is another key factor, with freezing, damaging storms (hail, winds), and heat as major concerns.
It needs more than efficiency. It's a great way to produce flavor and nutrient-dense food, but is almost unusable for calorie-dense food. That has to change before it's more than an interesting idea.
And of methods for doing that, irrigation is the most effective. This speaks directly to Liebig's Law of the Minimum, which states that whatever factor is most critical in limiting plant productivity is the one whose adjustment will have the greatest impact on productivity. For plants, water is a cheap addition, it's frequently the critical missing factor in increasing land productivity, and will literally take you from 0 to 100% alone.
(https://en.wikipedia.org/wiki/Liebig%27s_law_of_the_minimum)
By this reasoning, "vertical farming" is taking land as the limiting factor and literally requires building more land, substrate, water, sunlight, and nutrients in order to increase areal productivity. This is close to a maximally expensive expansion option. To date, vertical farming has been utilised only on very high-value crops, or those for which freshness is at an absolute premium. (Fresh crops can be moved across and between continents in days or hours, though quite often a 14-day transport with refrigeration retains freshness.)
For bulk cereal staples, overall land area remains the principle limiting factor, with sunlight, water, topsoil, fertiliser, and pest control as principle inputs. Weather is another key factor, with freezing, damaging storms (hail, winds), and heat as major concerns.