Urban Agriculture: Gotham Greens

[Broomstick]

A company called Gotham Greens is opening up their second greenhouse in Chicago..

I am intrigued by such projects.

First, because I've done hydroponics myself, although nowhere near on this scale or with this precision. Nonetheless, it's obvious to me why they concentrate on greens: greens are stupid easy to grow hydroponically and you get a lot of "bang for the buck" because you can eat almost the whole plant.

Second, the whole notion of urban farms tickles my fancy. Cities have long been dependent on "importing" their food, modern cities even more than in the past. Growing food in place definitely appeals to me.

Now, I also know that such an enterprise is not necessarily a plus - it all depends on how it's run. The plus side of this is that Gotham Greens is building their greenhouses in the old Pullman neighborhood, which is definitely an inner urban site. The new greenhouse is on the site of an old steel mill, so they're repurposing a brownfield site instead of paving over current farmland or nibbling away at what's left of greenspace and wild areas. They've also built greenhouses on rooftops, which again, brings agriculture to inner urban areas and expands growing areas without reducing greenspace. The methods they use utilize less water than traditional soil-based agriculture, does not require pesticides, reduces losses to pests to near nothing, and they apparently use solar, wind, and other renewable power sources when possible. Some of their operations make use of rainwater catchment, which helps with excessive stormwater in cities. This makes for year-round growing in optimized conditions, leading to much higher yields per unit of area than soil-based agriculture, with the ability to stagger production cycles rather than having a harvest glut only once a year. They employ local people in economically disadvantaged areas, making fresh, local food available to inner city residents. Much shorter transportation distances to market means much smaller carbon footprint in regards to transportation.

However, I still have my concerns. For one thing, they're building on the site of a former steel mill. Granted, they aren't trying to plant anything in the ground, but steel mills are not the most human-friendly places. By using hydroponics there is a lot less worry about soil contamination, but I'm still hoping there's been some sort of remediation done. But let's assume the site has been rendered safe for this purpose. I also am wondering about resource usage - yes, this does use a LOT less water than traditional agriculture, which is to the good even in an area like Chicago which has abundant, usable fresh water but for about six weeks of the year Chicago only gets about nine hours of sunlight a day and that's assuming the sky isn't heavily overcast which, I assure you, it often is during December and January. This means that in addition to whatever power is required to run the liquid nutrient, circulate air, and so forth they'll need artificial lighting as well. Plus probably some heat during at least the coldest part of the winter (some of their rooftop farms do utilize waste from the building they sit on top of). The nutrients in the growth medium have to come from somewhere - where are they sourced from and how sustainable is this whole operation, really? This is a site that uses advanced technology and all that entails.

So... less use of water and pesticides, but technologically intensive and potentially power hungry (which might be mitigated or even entirely balanced by cunning use of alternative energy).

So... what do you all think? Is this sort of agriculture the way forward for humanity? (It will not replace all other forms of food production, of course). Or is this something that isn't quite as good as it initially appears?

(I am amused that their produce can not be certified "organic". I know why that's so - the "organic" classification involves soil agriculture and how "natural" it is, and hydroponics is definitely not "natural". But it's almost certainly healthier and more nutritious, likely fresher and without even "natural pesticides" so really, it's likely more what the crunchy-granola crowd actually wants.)

[Eulogy]

Obligatory references to Batman and his rogue's gallery inserted here. :p

But seriously, this sounds like good news.

[Broomstick]

I think one of my concerns is that it seems too good to be true.

Of course, the company itself is selling itself as a good thing, that's one way companies stay in business. Certainly, hydroponics is more efficient in many respects than soil agriculture. But I wonder about the logistics of running massive greenhouses in a temperate environment. Just how energy efficient is this? And, again, where are the nutrients being sourced from?

If this is as wonderful as portrayed I'd love to see these sorts of greenhouses in cities everywhere, or at least in large urban centers. Humanity is more and more living in cities and this sort of food production would make such existence more sustainable.

I also wonder how feasible this would be to grow other types of a food plants. If, for example, you grew hydroponic tomatoes (quite possible - my dad did it for years) sure, you get great tomatoes but the rest of the plant winds up as waste. Ditto for things like zucchini. In more traditional agriculture you can plow it under or compost it or (for some but not all crop plants) use the part humans don't use for animal feed. What do you do with it in commercial scale hydroponics?

[NoDot]

Obvious solutions: burn them as biofuel during winter and compost them for nutrients. Not sure how easy the later is.

[Broomstick]

You could compost the non-edible plant parts for use in soil agriculture, but hydroponics isn't simply a matter of grinding up plants and routing sludge through pipes - the nutrient solution is mostly water, to the point it even looks like water. The nutrients are added in a fairly pure chemical form. It is no doubt possible, but perhaps not economically feasible.

Although using the "waste" as biofuel to heat the greenhouses in winter might be an option....

[Zaune]

Mulching it to use as a growing medium might work as well. Is there any reason they couldn't implement a hybrid system, and have some old-fashioned planter boxes in greenhouses with a nutrient solution feed to complement more traditional methods?

[Broomstick]

Yes.

Because that's not how hydroponics works. A "mulch" growing medium would rapidly rot and become a paradise for fungus and various pathogens which will do very bad things to both the hydroponic plumbing and the plants themselves. Hydroponic substrates are typically inorganic, inert stuff, it's just something to give the plant roots something to hang onto.

Sure, make a mulch sort of thing available to the neighborhood for landscaping purposes, or render it into biofuel or animal feed, but what people can't eat out of a system like that is, essentially, waste as far as the system is concerned. You'd have to find some other purpose for it.

Although, potentially, you might be able to get some use out of it as fish food if you want to set up an acquaponics facility with, probably tilapia or carp.

[madd0ct0r]

Doesn't detroit have monster winter storms?

Just like trad farming, it might be they just dont bother growing stuff over winter. Better to empty the beds, dissasemble / winterise the glass and start system cleaning and repairs when it dosent hit cash flow.
Seems less risky then losing a greenhouse + crop+ all money invested in crop after a pane gets sucked out in a storm

[Broomstick]

Having lived in both Detroit and Chicago...

Chicago arguably has worse weather, and certainly higher wind speeds. Detroit has more problems with ice storms.

In either case, people have been building and using green houses in both locations for a very long time. The Gotham Green greenhouses are industrial buildings and not something to disassemble.


And unlike traditional farming, where a field's produce is all planted and matured at once, plantings in a greenhouse operation like this are staggered, so there are always rows just started, more growing, some others reaching maturity, some post-harvest.... it's the ones post harvest that you clean and maintain before starting another round of growth. You can see that staggered harvest here:

There's really no reason to stop growing stuff over the winter so long as heating costs, and during the darker months supplementary lighting costs, don't become prohibitive.

After thinking about the issues of "what to do with plant parts you don't want to eat" I'd say that for a city as a whole mulching it and turning it into compost which can then be used to rehabilitate depleted soils throughout the city in parks, roadside plantings, and available to more traditional community gardens would be a good use. The problem in regards to a company like Gotham Greens, which is a for-profit enterprise and not a charity, would be giving it away for free. That's not insurmountable - many private enterprises nonetheless donate in various forms to the communities in which they are situated (my employer donates money to food pantries and similar charities, as well as giving each store director a budget for contributing to local organizations above and beyond that as an example) and there is probably a way to structure a transfer of "mulch" from a private greenhouse to a city in a way mutually beneficial to both. Municipal mulching/composting operations already operate in many places as part of the waste disposal system so it may be a simple as taking away the greenhouse waste at no charge so they greenhouse doesn't have to pay to get rid of it, rather than the greenhouse launching another enterprise.

[Zaune]

They could also branch out a bit, pardon the pun, and use it to rehab some of their own land for crops that don't do well in a hydroponic system: Fruit trees, for example.

[Broomstick]

You're talking about a company that, up until Pullman II, used the rooftops of other peoples' buildings for their projects. This is not a company that owns a lot of land.

[Raw Shark]

I think animal feed is probably the best use for waste material. Mulch and compost for parks and traditional public gardens is all well and good, but chickens will eat pretty much anything, and are an excellent and ongoing food source. Keeping chickens on the roof is a longstanding tradition in Brooklyn, at least, and even became legal there a couple of years ago. Different buildings could probably even work out a cashless "feed-for-eggs" barter system if they wanted to. In poor-ass inner city areas, a lot of people working in the gardens would probably gladly accept a carton of eggs or two a week as a bonus to their paycheck that (other than concerns about cholesterol) also keeps them strong and healthy.