Comment by gus_massa
11 hours ago
I agree. Potatoes transform light into starch. With traditional farming you get a huge "free" solar collector. In vertical farming you have to pay for the light.
So the alternative is to grow lettuce that has a greater price to energy ratio.
More than just light - the chemical profile of the soil is the feedstock for all of the interesting chemistry the plant does. The air can provide oxygen, nitrogen, hydrogen, and carbon, which are the backbone of a lot of the chemistry, but anything more exotic than that is coming from the soil. They're factories, not alchemists.
Hydrogen comes from water. They have surplus of Oxygen from CO2 and water, so much that they give it away. Carbon comes from the CO2 in the air.
Other nutrients like phosphorus or potassium come disolved in water, but in intensive farming they must be added to the soil, so it's the same that dissolving in the hydroponic solution. Perhaps it's more efficient in hydroponic than in soil.
Nitrogen is more tricky. There is plenty of Nitrogen in the air but not in a useful form, so in most cases it must be added as fertilizer. In some cases like soy the plants have helper bacteria that transform the nitrogen from the air into useful forms. This conversion takes a lot of energy, so I don't expect the lack of wind to be a problem, you still need some air movement to keep the CO2 high and the O2 low. (Anyway, farming soy under artificial light is probably not profitable for the same reason farming potatoes under artificial light is not profitable.)
The most important thing you lack inside a vertical farm that you get almost for free in a big faring field is sunlight (i.e. energy).