Calories = Light (energy) + Fertiliser.

Efficiency of an LED is like 40%, and Photosynthesis efficiency is like 2%.

In other words calories are expensive and ineffieicent to produce through artificial lighting, no amount of 'startuping' will change that.

Also nothing here is new, we've had greenhouses, artificial lighting, hydroponics, aquaponics, aeroponics and even vertical farms like 50 years.

Production of electricity from wind turbines fluctuates a lot. So does the price. I wonder if there are plants that you can give light when it is windy at any time of the day and leave in the dark when when electricity is expensive.

Already, wheat fields can be tilled and harvested by autonomous combines. Direct human labor is basically down to picking fruits and vegetables. Most of the time, it's going to be cheaper growing something outside, in the sun and dirt that's already there.

Well technically, if you could increase the photosynthesis efficiency then it might. There are projects that aspire to do just that. If the results are somewhat fragile and wouldn't survive in the wild then this could work in combination with greenhouses or vertical farms. But yeah, that's quite speculative and until it happens I agree that the energy budget doesn't make much sense.

I didn't claim they were.

But Salads are a good way to get a whole pile of principles figured out (contamination, environmental effects on the gear, basic robotics, deals with potential customers and so on).

> Bulk foods (wheat, potatoes, sugar beets, cassava, rice) cannot be grown efficiently in such vertical farms, at any scale, with current technology.

That's true, but that's also not where the next move would be. Bulk foods (more properly called staple foods) do just fine in regular soil where ever they are being grown, and do so reasonably efficiently.

But for cucumbers, tomatoes and a whole pile of other veggies vertical farming quite probably will work just fine and cost competitive with normal greenhouses.

A vertical farm does not compete with in soil agriculture in open air, it competes with greenhouses. Staple foods are an entirely different class of problem.

In IT terms: don't complain that the more efficient CPU factory doesn't make your memory faster, it isn't meant to do that.

I know you didn't, but (without wanting to put words into your mouth), the more abstract claim was that there is some sort of technology path from growing salads to growing other crops, which (I'm claiming) there isn't, or at least not to a significant degree. The things you mention are already solved, have been for many years; it has been a specialty and major export product of our country for decades (as you indubitably know).

"Bulk foods (more properly called staple foods)"

I didn't use that word on purpose. What I roughly wanted to say was "root crops, grains, tree crops, basically anything that isn't herbs or salads", but that wouldn't be accurate either (carrots are root crops but not a staple and can to some degree be grown in substrates). But probably it's a distinction without a difference, in this context. I think it's fair, for the sake of the discussion, to talk about "leafy greens" vs "non leafy greens", even though "but tomatoes" etc.

"Bulk foods do just fine in regular soil where ever they are being grown, and do so reasonably efficiently."

No they do not, at least under other circumstances than precisely the ones we want to get away from, with indiscriminate use of nitrates and pesticides. I happen to have a yield model for various crops in the EU here open on my other monitor, that I've been working with for several months now. Agriculture as we do it today in the western EU cannot be done efficiently without intensive farming methods. Without fertilizer, yields are a factor of 2 to 4 lower. That is an absolutely game changing difference.

"A vertical farm does not compete with in soil agriculture in open air, it competes with greenhouses."

Well I'm not sure any more what we're arguing here. The OP's point was "Vertical farms don't feed people. They are basically a solution to just in time delivery for restaurants and nothing else." Which, to some degree, holds for greenhouses (depending on definitions). The food production problems we have is not that we don't have enough area for greenhouses, or that we can't grow enough leafy greens; greenhouses are so efficient that we're not constrained by land for the demand we have for food that can be grown in them. What we need is more space efficient production of high calorie foods, in ways that don't degrade the environment in the ways and to the extent current methods do. Neither vertical farms nor greenhouses (I mean, 'vertical farm' is just a marketing word for 'multi story greenhouse') will be of any use for that.

But maybe your point is something entirely different and relates to the OP in a different way, in which case our whole discussion is moot.

I disagree with that 'feeds some restaurants', regular consumers take in far more in terms of leafy greens, tomatoes, cucumbers and a raft of other vegetables besides than the restaurants do (in particular right now, but also under more normal conditions).

If anybody cracks the staple foods under glass problem with any degree of efficiency that would really be a game changer but this vertical farm option is already quite impressive from what I've seen. There are some interesting trials underway in NL by people that at least seem to know what they are doing.