Quantifying Community Garden Crop Yields

An informal study looking at the urban farming yields, by Mara Gittleman67 gardens, with a total area of 1.7 acres in NYC generated 87,000 lbs of food, with a market value of roughly $200k in 2010.  This is equivalent to about $3/square foot.  Just looking at the financial aspect, if we’re talking about land which could be developed, the net present value, discounting at 5%, of $3/sq ft, is (even if we go out 100 years) only about $60/sq ft. If you build a 5 story building, then property values need only be greater than $12/sq ft for the urban farming not to make (economic) sense, and I’m going to go out on a limb, and guess that property values in most of NYC are, um, substantially higher than $12/sq ft.

Why Urban Farming is an Awful Idea

20100708105423 by Zane Selvans on flickr

Boulder County is looking at some kind of county-wide sustainability program, with an associated tax which will be on the ballot this fall.  The City of Boulder is revising its Climate Action Plan, looking toward a goal of climate neutrality in 2050.  An extension of the tax which supports our climate work will also be on the ballot in the fall.  One thing that none of that money should go toward?  Urban farming.

Continue reading Why Urban Farming is an Awful Idea

Industrial Scale Urban Farming in NYC

TED fellow Viraj Puri talks about his Brooklyn rooftop farming startup.  Gotham Greens has ~1500 square meters of hydroponic greenhouses producing herbs and salad greens in a very controlled environment… somewhere between a farm and a manufacturing facility.  The system is solar powered, and can operate all year long.  They currently produce ~100 tons of food a year, and they believe the business is viable at least in the urban foodie context.  I was happy to see Puri readily (repeatedly) admitting (or even pointing out) that the system cannot scale up sufficiently to provide a large proportion of the city’s overall food requirements.  This is in stark contrast to the idea of Vertical Farming, which is clearly bunkum — once you’ve covered the roofs with greens, there’s no more farming to be done unless you pipe in light somehow, which is much less efficient than simply farming where the light is naturally.

Just out of curiosity… I wonder how much food could be produced in Brooklyn at full capacity?  And roughly how much does the city eat?  The land area of the borough is 183 km^2 and it has 2,500,000 residents, or roughly 75 m^2 per person.  Their production of 100 tons/1500 m^2 is roughly 66 kg/m^2 per year.  So if the entire area of Brooklyn were producing like this greenhouse, you’d get nearly 5000 kg of food per person per year.  The average American consumes about 1000 kg of food per year, so if you were able to use 20% of the borough’s area, you’d be close to meeting demand… at least by mass.  Gotham’s 59kW solar array probably takes up ~590 m^2 (100 W/m^2 is typical of solar cell power production) and only provides part of the operation’s power.  Probably there’s other infrastructure too that’s not actively producing food, so say they’ve got about half their total area dedicated to actual plants… then you’d need to get up to 40% of the land area being utilized to get 1000 kg of greens per resident per year.  However, most of the 1000 kg that we actually eat is a lot more energy dense than lettuce.  I wonder how many calories per m^2 one can get out of these setups, and what the most productive crops would be?  Honestly I’m surprised at how large the potential production is.  I wonder what the actually available rooftop area is?

California Dreaming

An hour long interview based documentary by some Dutch filmmakers about the changing social and economic realities of southern California, in the wake of the financial crisis, and America’s general malaise.

It’s dangerous to cling to an identity which is no longer compatible with reality.  Remember the Norse and their Greenlandic colonies.  In the long run I think adaptability is the greatest kind of power you can wield.  Evolutionary power.

We need, in so many ways, to move beyond thinking of ourselves as consumers, instead of citizens.  Consumers, instead of producers and creators.  Society and culture are almost infinitely flexible, if you’ve got the right mindset and a reason to change.

Links for the week of June 26th, 2010

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Continue reading Links for the week of June 26th, 2010