How much food can you really grow in a city? You’d be surprised. | Hacker News Reader

How much food can you really grow in a city? You’d be surprised.

boston.com

12 pointsrobg29 comments

Probably the world's number one example of urban farming is Shanghai: "The magazine Urban Agriculture describes how Shanghai has in effect created a nutrient recycling zone around the city. The municipal government manages 300,000 hectares of farmland to recycle the city’s night soil. Half of Shanghai’s pork and poultry, 60 percent of its vegetables, and 90 percent of its milk and eggs come from the city and the immediately surrounding region. " (source: http://www.earth-policy.org/Books/Seg/PB2ch11_ss4.htm)

Of course, you're not going to this kind of scale from scattered community gardens.

Havana, Cuba is another successful example: http://www.foodfirst.org/en/node/273

Ewww, 'night soil'. Rinse and peel those vegetables carefully, Shanghai.

If you are interested in this sort of thing I highly recommend checking out Path to Freedom.

"The yard has over 350 varieties of edible and useful plants. The homestead's productive 1/10 acre organic garden now grows over 6,000 pounds (3 tons) of produce annually."

http://www.pathtofreedom.com/about/urbanhomestead.shtml

This wasn't about how much food she is growing. What was surprising?

Also check out Zolt's square foot garden project that he is doing with his kids:

http://www.toddalewis.com/square-foot-gardening.aspx

http://news.ycombinator.com/item?id=538503

I like how she is "just doing it". As described, it's not primarily part of or subservient to some "agenda". Seems rather "hackerish"; hacking the local setting to combine urban and rural elements in a mix that suits her.

My one caveat would be to make sure your soil is safe; urban settings have trouble with contamination, from "brown fields" to lead paint, motor oil, etc. The problems can be remediated or worked around; the thing is to know about them so that you can do so.

I think the HN crowd is more likely to understand this safety issue. My challenge when talking with friends who start urban gardening is to point the concern out without sounding negative about their project. I'm really just concerned for their health; as long as that is assured, more power to them. Unfortunately, I think sometimes my attempt to be helpful in this regard just comes across as negative.

What is the impact on the food produced of growing plants in soil contaminated with lead paint or motor oil, for example?

The food has lead or other contaminants in it.

I'm not sure that's true. I've read that heavy metals in motor oil are not absorbed into plants growing in contaminated soil.

Can you show otherwise?

And what is the effect on filtered water of water contaminated with various substances?

i think (without proof / reference) that plant is harder to fool with. if the environment is not suitable (too much heavy metal, salty water, too acidic/basic) then the plant either die or grows very slowly and it's not pretty (colorful leaf due to excessive iron), basically you don't want to eat it just by looking at it

animals, on the other hand, are much easier to fool with. here, bad people 'rejuvenate' 3-days old meat by soaking it in formalin and fresh blood.

actually, i meant to say that animals are more hardy/sturdier than plants; thus, can sustain more abuse/pollutions

NB: there are hardy plants that absorb heavy metals (like water hyacinth) by simply growing too fast, they are employed by water treatment facilities ... but people don't normally eat those plants, maybe not edible

Various members of the mustard family are used for phytorememdiation. People eat many members of the mustard family.

You realize, right, that you are reasoning from a very shaky foundation and using that reasoning to make advice about health and safety. My advice: Don't do that any more.

"Various members of the mustard family are used for phytorememdiation. People eat many members of the mustard family."

it's akin to say "water is used to clean dirt. People drink water"

for every hypothesis, there will always be special case(s) to refute it.

thx for your concern, but really, i'm more interested in what you say about the topic: what should we eat? where can we get the polutant-free food?

Along that vein, I'm curious about the inflection of this quote regarding her homemade prosciutto: "It proves you can make really good pork off of dumpster scraps." I hope it's sarcastic, or saying that she would have thrown the pork away otherwise, but something is nagging at me to take it at face value. Some chemical contaminants might actually taste good.

I took that to mean she was feeding pigs dumpster scraps. Not sure, though.

Oh, good point. I read Charlotte's web so long ago that I forgot to think of what pigs ate. Still, hopefully the slop she's making is from scraps that never made it to the dumpster, otherwise the same concern about contaminants applies.

I wouldn't consider it much of a concern - people can live just fine off of dumpster diving. Tons of perfectly edible (much less "contaminated") food gets thrown out.

the very fact that she still is alive to tell the story negates the safety issue (i imagine the concerns are trumpeted for decades toward her, not new thing)

she's probably healthier than those safety-conscious people who buy groceries at wal-mart

by volume, plants are consist of carbon, oxygen, and nitrogen, phospate, potassium; thus major elements. they do take CO2 from air pollution to grow. motor oil, if it ever breaks down, probably will just supply C and O. lead is not even a trace element, average plants probably don't take Pb and if they do, probably extremely minute, like 0.0000001% (# pulled out of my ass)

maybe just washing it with baking soda and rinsing it with running water is sufficient, probably overkill -- don't worry much about plants, they are normally safe, that's why you rarely read news about people got killed by eating plants.

i'm starting urban gardening too (i played with aquascape before) ... it will be interesting

Lots of 'probablys.' You should probably do more reading and less writing.

There are elevated lead levels around "civilization" due to human activity. (Lead paint, tetra-ethyl lead in gasoline, pesticides, etc). Food crops vary in the degree to which they accumulate lead, but they do. In general, the skin of roots and tubers have the higest levels and fruits the lowest. Keep in mind though, stems and leaves can have higher levels, particularly since various members of the mustard family (which includes broccoli, cauliflower, brussel sprouts, etc) are deliberately used for phytoremediation of lead.

fine, can you point me the cases when someone die due to lead poisoning from eating plants alone?

my point is that the amount of Pb is minimal in plant, esp if you wash&clean it. you probably will get more Pb from eating pesticides, inhaling gasoline or licking the paints

the more reading you do, the more you will be asking questions. some of conclusions i had in past years are now broken. i keep learning stuff -- so really, i don't have absolute knowledge about anything ... but it's okay

Plants absorb water, and the water may have chemical contamination.

It's exactly the same way that it works in animals.

Different plants are affected to different degrees.

Counterpoint; Will Wilkinson on urban farming: http://www.willwilkinson.net/flybottle/2009/07/08/urban-farm...

It isn't clear exactly what he is arguing against. Does he take exception to the term "urban farming" because it contains the word "farming"? What is the connection between the fact that farmers in Iowa overgrow a handful of crops because the government pays them to and people wanting to garden in the city?

Lest anyone doubt that corn is overproduced, here are some actual numbers:

http://www.card.iastate.edu/iowa_ag_review/winter_07/article...

See the paragraph titled "Corn Utilization and Surpluses for 2004".

This of course wouldn't be a problem if it weren't for the fact that we (US taxpayers) pay for it. The artificially low price of corn has also led to a glut of processed garbage being sold back to us.

And don't forget how its spurred other perversions, like the corn ethanol industy.

Well, as I read it his argument is that it's totally fine if people want to garden in the city, but that they shouldn't extrapolate that to mean that we don't need the vast spaces dedicated to agriculture that we have in, say, Iowa.

I've heard that city soil can be highly contaminated. I wonder what the best way to deal with this is?

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