This is a fairly good intro video to the method:
I only spent ~£30 on all of the supplies to set up my system and have grown lettuce, rocket, spinach, tomatillos, and peppers in my apartment. It's fantastic and simple and will allow me to have a supply of fresh green food after Brexit.
If you’re interested in hoby hydroponics, it’s a great way to start.
Here's a link to the original Kratky paper on the method:
I've been running this over a month now. It's mainly a proof of concept before I invest in some proper led grow lights next winter. Works great so far, my basil plants are doing fine and will move to the balcony when the temperatures rise a bit. There's enough room to have two or three small plants below the lights. Two healthy basil plants translate into an enormous amount of pesto if you treat them well. I must have harvested several kilos last year by the end of the summer. That's starting with two anemic supermarket plants.
This improvised kratky system probably uses a bit more. I would say it's probably 10x or worse. I've seen some fluorescent systems similar to what the lady in the video uses starting at 140W. But you can get bigger lights. LEDs are probably more efficient for the same amount of lumen.
If you live in a high-cost city, the best thing to grow in your backyard from an environmental standpoint is probably an ADU (backyard cottage for someone to live in), and the best thing to grow in your spare bedroom is probably a roommate. Displacing walking-distance housing to do farming is a huge loser from a climate perspective.
Of course there is more to life than emitting as little CO2 as possible, but to the extent that urban farming has environmental benefits, it is in exploiting niches caused by shitty land use decisions in the past and present.
(By way of illustration, the average car commuting 20 miles each way every weekday for a year emits 4.6 metric tons of CO2, so according to the article you could grow and transport something like four and a half tons of greens for the same carbon footprint. Maybe I'm weird but that's a lot more than I go through in a year.)
The point being here is that this is not a zero sum game; there are many benefits to growing stuff other than producing food.
A lot of the vegetables grown in Dutch greenhouses mentioned in the article are actually exported; though other countries are starting to do the same now.
This area here is the most well known and largest greenhouse area in the Netherlands (and probably world wide). It's comparatively tiny (about 100 square KM). https://firstname.lastname@example.org,4.233423,25389m/data=...
The reason greenhouses are used there is because they produce way more per square meter than traditional farms can. That and access to cheap gas decades ago caused a boom in greenhouses to happen. Currently many of these greenhouses are switching from gas to clean energy. Over the last 4-5 decades, local farmers have optimized their production and they now run very efficiently.
The Netherlands is (by far) the largest exporter of tomatoes world wide. Most of those are grown in these and similar facilities as well as many other crops (i.e. this is not dedicated to just tomatoes). It's a vastly more efficient way to use land. The point here is that it doesn't take much space to feed a city.
For example, fresh herbs cost a fortune in grocery stores here, and are festooned with single-use plastic packaging, and come in far larger quantities than one can reasonably use before they go bad. So it makes tons of sense to have a little herb garden in your house or yard, especially if you can grow things that are adapted to your local climate (e.g. my rosemary bush is taller than I am).
But I think the optimal scale inside of expensive cities is probably closer to "houseplants that you can eat" rather than an urban farm.
My mother is an amazing gardener because she pays careful attention to her crops and applies reasoning and careful experimentation to grow her knowledge.
Have patience, read up, and dig in. You can grow things yourself too.
Perhaps I’m becoming a Luddite...
1) I redid the calculations using the numbers shown in the table. With more decimal places, it's 1.054 for outdoor and 1.036 for indoor. The actual penalty for outdoor growing, using their own input numbers, is more like 1.7% than 10%. Presenting the results rounded to 1 decimal place is misleading.
2) The only reason indoor comes out ahead at all is that they gave indoor lettuce a 0.18 kg credit for sequestered CO2 and gave the outdoor lettuce no credit. Plants absorb CO2 while growing regardless of whether they are indoor or outdoor. In the case of lettuce, there is no long term sequestration anyway; the plant matter is soon converted back to CO2 when it's metabolized by humans or microbes. Setting both indoor and outdoor sequestration credits to 0, indoor has a CO2 footprint of 1.253, significantly larger than outdoor's 1.054.
The original source for the table is cited as a blog article from the Breakthrough Institute titled "Don't Count Out Vertical Farms." I tried going back to the original source to see if the numbers were misrepresented here, or if they had more justification in the original, but the Breakthrough Institute appears to have removed the article from their site. Existing links to it 404 now.
It gets worse when you look at the footnotes. They assume that the electricity going to the vertical farm is produced at the Swedish average carbon intensity per kWh. Sweden is far below the OECD average for electrical energy carbon intensity:
Only Switzerland, Sweden, Iceland, and Norway have low enough electrical carbon intensities for vertical farming to have a smaller carbon footprint, even conceding the re-forestation assumption.
Growing under artificial lighting can produce crops that don't need to endure prolonged storage and shipment. Some people will pay a flavor-and-quality premium for things like fresh tomatoes, salad greens, and herbs that can be grown this way near the point of consumption. But the bombast about remaking the "global food system" this way is ridiculous. The vast majority of crops, measured either by dollar value or by calories eaten by humans, are not going to be grown this way. For most crops it would greatly increase the cost and the fossil fuel consumption if they were grown under artificial lighting, and there wouldn't even be a corresponding quality improvement to motivate buyers.
The article even says as much:
In fact, all things considered, says Mark Bomford, director of the Yale Sustainable Food Project, “it’s generally a lower-impact proposition to move food around the planet than to move the climate.”
If I wanted to get potatoes right now from the back yard dirt I'd have to remove about two feet of hard-packed ice and snow, then chisel into dirt that may as well be concrete. At least solid ice and concrete respect a pick. Wet, frozen dirt just shrugs it off.
Let me remind you that this year in places like Minnesota it was -60°F outside. Good luck getting anything out of the ground in those conditions. Even a backhoe is going to have trouble. I'd suggest using dynamite, but at those temperatures even dynamite won't work without being heated up first.
And the study that suggests indoor grown can be less carbon intense is super interesting.
A big dirty secret is that organic crops fail at both. Farmers buy special organic pesticides, for example toxic plant juice. The fertilizer is often poo.
These indoor farms are kept bug-free. They should also be free of rats and birds. If a bird craps on your lettuce, there is no way to really fully sanitize that without destroying the lettuce. You can wash it so that it looks nice and people will eat it, but you will never make it safe.
The farmers themselves are also a problem of course, particularly the lowest-paid workers who often don't get proper treatment for diseases and often don't really understand or care about sanitation. Indoor farms allow an easier transition to automation, which would greatly reduce this disease risk.
Or even do it inside.
I mostly work in climate inhospitable to farming, so I can't have a garden in my yard. But I still grow radishes, wheatgrass, and other small edible things in mason jars between the monitors and gadgets on my desk at work.
That's how the office found out one of my coworkers is terrified of crickets.
What would be really cool to see is an offshoot of this tech for greenhouses, or rooms with piped in sunlight, or leveraging geothermal energy, etc. Micro machines for apartments... So many possibilities!
Yes, you can grow leafy greens semi-profitably in urban environments, or in your garage.
How many calories do those leafy greens contain? Calories are what keep eight billion people alive. You may be able to grow salad garnish in your office, but good luck growing the 2,200 calories/day that the average adult needs.
There's no transition from this, to actually useful agriculture, just like how there's no transition from throwing a Frisbee, to putting a satellite in orbit.
Sorry.. are you saying the 'eat leafy green vegetables' thing is wrong? I understand your underlying concern is the lack of calories, but we don't eat purely for calorific content: vegetables have vitamins and fibre without which we get unhealthy.
Your 'useful' is what worries me. Please don't eat a diet absent any greens except on doctors advice.
However, growing calories is hard. It's really hard. It's just about impossible to, outside of a real, outdoor, field.
And we need to do it, to keep people fed. It's the hard part of feeding people. Urban farming of a small number of high-vitamin, low calorie crops doesn't solve a problem that anyone is likely to have.
$2 of rice (~3lb, uncooked) buys you 5,000 calories.
Lettuce is a garnish cash crop you can grow under a lamp in your garage. Rice is what will keep you alive, though.
Gardening isn’t all that hard in the first place. Put seeds in the ground, water occasionally. If you buy a sprinkler you’ll have a more reliable system than 90% of these arduino based 3d printers hacked into “growing systems”. Of cause for all the startups the focus is on the “IOT crowdsourced disruption” not about actual end user value.