The underground farm growing salad crops in a disused air raid shelter [video]

Also crops that need very specific conditions to grow might not do well as our climate shifts, and growing in a carefully controlled indoor farm could fill demand, though at a high cost.

- They can be harvested and then delivered to the customer the same day, some places will pay for this type of high end service

- Indoor crops grow quicker than outdoor ones due to the optimized conditions. For already fast growing crops like greens that means you can have more harvests per year.

- Being able to be located in a densely populated area greatly expands the labor pool

- Vastly improved labor conditions by virtue of being indoors and not bending over to the ground all day

We are already using of a large fraction of the arable land that is well suited to outdoor grain cultivation. It isn't clear that yields can be increased enough to feed people as we approach peak Earth population.

Indoor growing allows for an extension of agriculture to new land. Efficient Climate control, combined with high efficiency LEDs with optimized output spectra make the concept more viable.

It will be more expensive than current outdoor-based agriculture, but we'll be wealthier by the time this is needed.

However, they are great for specialty crops that require lab testing for purity and quality before being sold to the general public. These include crops like cannabis and mushrooms.

In the state of California alone there are nearly 40 million people. That is a big enough market to support allot of firms. ~O

There is a hudge market for

What about in places where electrical energy is abundant, and space is limited? Or maybe in locations where terrain is very difficult to farm on. Mountainous terrain provides a lot of potential hydro-power, but are terrible places to place farms.

Would a dam powered multi-storied indoor farm be a feasible solution in a situation like this? Not to mention, it could provide light 24/7.

Not being facetious here. Genuinely curious what the pros and cons would be to a farm designed this way.

Cannabis growers don't use grow lights in doors because it's more efficient. Sunlight, is the least of a farmer's worries.

Firstly, geography: there are places with somewhat long periods of darkness and/or cold, where agriculture is feasible only during the relatively short, but often intense, summer season. For example mid-to-northern parts of the Nordics. Indoor farming can deliver throughout the year.

Secondly, logistics/sustainability/locality: it's more sustainable to farm locally than to transport something from the other end of the world, or even from the other side of the country. I've seen onions from New Zealand in the shops here in the Nordics and it's probably normal but I thought it was downright weird.

Thirdly, organic farming: by being able to control the growth environment, the amount of pesticides and insecticides should be greatly reduced, maybe even down to nothing.

Fourthly, the known-unknown future: an ongoing major change in climate will likely make some of the nowadays arable land non-arable. For example rising sea levels threaten rice production in low areas of Asia, and so on. Dr. Gwynne Dyer spoke (in "Geopolitics in a Hotter World") of a rule of thumb where one degree (Celsius) rise in average global temperatures loses 10% of global food production. If we expect over 3 degrees then one third of global food production will be gone. Maybe that's OK if the world becomes better in logistics, but I think the key is to grow locally and indoor farming is possible basically anywhere.

Many people are commenting about how wasteful it is to use LEDs instead of sunlight. But again, as the owner says in the video, consumers expect produce all year round. That might not be possible in winter or poor light. The alternative is to import out-of-season food from abroad. Or to return to eating seasonal produce only. How many consumers are willing to accept that? Not many I'm guessing.

Also, the owner of the farm states he saves over 70% water use over conventional farming. That's a massive saving.

So yes, underground farming won't solve the world's food problems but it seems like it could play a role alongside conventional farming.

There is one thing missing from the video though: What do the crops taste like?

What about capturing and redirecting natural light, to replace or supplement the grow lights?

I've seen "light well" systems that direct natural light around the building using mirrors and tubes (e.g. in office buildings to decrease lighting costs and combat seasonal affective disorder), so this seems like a natural extension of that concept.

I especially loathe articles that state near the end that energy consumption currently is quite high, but that they are working on optimizing that.

You can not optimize your system out of the hard dependency between photons and photosynthesis. Period.

However, there is a simple 'hack' if you don't have mushrooms grown outside or treated with UV light. Place the mushroom in natural light (e.g. on a windowsill) for about an hour before you're about to cook them. The natural light will help raise the level of vitamin D in the mushrooms.

In case you're wondering about the veracity of this info, it's from a 2017 book published in the UK called How to eat better. The author is a botanist, science writer and TV presenter called James Wong. (He has appeared on a couple of BBC TV shows.)

Here is the relevant passage in full from the book:

> Doing one simple thing to your shop-bought fresh mushrooms can transform them from containing virtually zero vitamin D to one of nature’s richest food sources in as little as an hour or two, according to Penn State University. Popped on a sunny windowsill, the mushrooms (which commercially are grown in near total darkness) will react to the UV light, churning out loads more of the antioxidant vitamin to defend themselves from damage from solar radiation.

> The Penn State team found that a serving of white button mushrooms exposed to UV lamps for just 1 second could go from containing essentially zero vitamin D, to an astonishing 824 per cent of your daily recommended intake. When they tried the same thing with shiitake and oyster mushrooms, their vitamin D content skyrocketed way over a thousand times what you need to consume each day. In the world of food science, this really is as close as you can get to alchemy.

> With such tiny amounts of UV light needed to create such an enormous impact, it doesn’t have to be a blazingly sunny day for you to do this at home either – simply lay your mushrooms out on a windowsill for an hour or two anytime between 10am and 3pm and their levels should peak significantly. As the gill tissue (the brown underside of the mushroom caps) is more sensitive to light, placing them with the gills facing up will trigger the strongest spike. You can now even buy special vitamin D-rich mushrooms at a premium price in some posher supermarkets where this UV treatment has already been done for you. Just three of these mushrooms should give you your entire daily dose. But as tumbling your mushrooms out on the work surface for an hour or so will do the exact same job, you may want to save your cash.