Of course, with hydroponics you're using also 5-10% of the water you would be using for all those lawn and roof top gardens, where I imagine you'd have even more water loss higher in the air.

The author of the article should try growing his own hydroponic tomatoes before taking a bad example and letting that be the example for an entire variety of crops grown a different way. It's easy to grow a bug eaten, partially rotten, slug eaten tomato in the regular garden, with all the extra water and fertilizer, and removal of top soil, and say horizontal gardening doesn't hold a candle to hydroponics. It's just not cut and dry, at all.

Kitchen hydroponic gardens would beat out rooftop gardens and lawn gardens. Of course, I love the idea of lawn gardens, as it's useless space anyways and a patch of grass just doesn't look nice anymore.

let's have 'em both.

The economics of farming suggest that you cannot build new buildings to support urban farming. Reuse of low value older buildings may be possible in certain areas.

Most newer commercial and industrial buildings will have too little sunlight penetrating sufficiently far into the building to promote rapid plant growth. And the high humidity levels and water runoff are likely to promote rot, mold and rust.

Some portions of some buildings are certainly suitable for food production. Rooftops have a lot of potential. It may be that some buildings become hybridized with gardens near the southern windows while other uses happen further inboard.

A great deal depends on the crops grown, productivity and market value of the crops, as well as labor and support costs. Crops that can now be grown economically in greenhouses might be most appropriate for other building types.

High tech, high rise towers with advanced and complicated systems make for lovely illustrations, but are almost certain to never be built. Many crops - even at ten times their current prices could never be profitably grown in one of those buildings.

Besides, most cities have a substantial amount of available land that can be intensively farmed or gardened. The best increment for this will be on the individual, neighborhood or small business scale, which is also most receptive to intensive farming methods that boost yields. If everyone in New York City grew just two containers of tomatoes on their fire escape or balcony, they could produce 85,000 tons of tomatoes a year. Imagine what could happen if this became a concerted effort.

Roof top gardens aren't an answer. Believe it or not, there are not enough roofs in Manhattan to feed everyone on the island. Density is good, don't get me wrong. I'm all for the end of sprawl.

Besides, most of the buildings roof couldn't hold the weight anyways. Imagine how much weight would be added on a building if you had a fruit tree grove.

i agree with zaxxon, we should have both. i see the vertical gardens as a great opportunity to have a controlled environment in which to grow non-local foods that are usually shipped from very far away, like bananas, oranges, and mangoes.

I also agree with Zaxxon, because, as Dallas pointed out, there isn't enough room on roofs. We need to use every space we can without losing density. As a landscape architect, I'm very much in favor of using parks for food production, and not just because it might lead to me getting to do really cool projects. In some cases, I think we over use turf grass in parks just like we do in suburban lawns. I realize the turf is important for recreation, but often its used just to cover ground as well. This leads to a lot of extra maintenance. Part of the purpose of a park is to reconnect people with nature. Recreation and conservation are important parts of this connection. If we only use parks for these purposes, though, it's easy to see nature as one big playground and forget that our lives are connected to it through the food we eat and the water we drink. Hydroponics is great for producing food where and when we can't, but it disconnects plants from the soil. Soil substitutes don't have all the microorganisms that plants sometimes need to be healthy and healthful.

Why'd people stop growing their own food in the first place? I don't think it was just about a division of labor. I think a lot of it had to do with dealing with the pests and vermin that food we eat attracts. Yes, even rooftop gardens are going to be susceptible to things like rats. So what's the solution? Cats?

I just want to make sure whenever we're talking about stuff like rooftop or kitchen or victory gardens, we talk about organic growing methods as well. It would suck to live somewhere where they were using pesticides all the time.

So, while I'm all for moving food production to where it's used, I'm not for moving certain agricultural practices into closer proximity with higher population densities.

There really aren't enough roofs in cities to grow enough food to feed the people there. That is the price of density. However, there is enough room on city roofs to catch enough light and wind to provide a large fraction of the power those cities use. Manhatten has a land area of 23 square miles or so, which means that, averaged over a day, it is receiving about 9.5 GW of solar power (assuming 4 kWh/m^2/day) for 1.6 million people. 20% efficient solar panels covering all the roofs could easily light, heat, and cool all those buildings, and power all the electronics and appliances, with enough solar thermal left to provide hot water. Maybe a few efficiency improvements would be needed, but nothing that isn't doable. And small wind turbines atop buildings would be very cool.

As for vertical farms, they do have a place. It depends how far into the future we are willing to look, or how bad environmental degradation gets. In another century, or earlier if climate change drastically reduces the availability of arable land (pushing up food prices greatly and threatening massive starvation), I could imagine the following scenario. You have a several story building with highly efficient solar panels on the roof. You use the electricity to power LED's that give off the wavelengths to which plants are most photosynthetically sensitive. This would allow you to grow plants that incorporate far more than the

Sound far fetched? For now. But who in 1900 would believe in GPS, the internet, laptop computers, or genetically modified foods? Humans have done amazing things, so let's not sell ourselves short. We can do amazing things again.

While "vertical farming" is an interesting idea in concept, personally I think it's a pipe dream.

So instead of relying on conventional green spaces that exist we're going to build more infrastructure, using more materials and more machinery to create or modify existing structures for these vertical greenhouses?

One poster already mentioned the fact there generally isn't enough natural light in conventional structures to grow crops. And without some massive construction there wouldn't be enough light in custom designed building either. (unless you add rows upon rows of grow lights sucking more power from the grid) Now let's talk about getting all of the resources to these crops, we're talking pumping systems for irrigation, soil amendment delivery systems, moisture control ( today's office towers are not designed to deal with the kind of moisture that is even remotely required for indoor growing of plants.) drainage etc... etc... etc...

Why are we trying to re-engineer society so it fits our reality? Isn't that mentality what got us into the environmental crisis we face now? Sure vertical farms sound good on paper and make a great photo for a blog entry but they don't sound too great to me.

So what is the solution? Well why not revert back to convetional gardening and farm methods we know. Techniques used for centuries that are in tune with nature. Great in summer you say, but what about winter?

I live in Winnipeg Canada, we have 2 month stretches in winter where it gets down to -40c (-40f) overnight. The university in my city has run tests on unheated passive solar, high thermal greenhouses (think concrete inside being heated by the sun during the day and the greenhouse being covered with a thermal blanket at night) that made it through winter never going below freezing without a heater. So we know that even in the harshest climate there are real technologies that use standard methods to grow crops year round. (Add even a wood stove to that and you're really set).

But where are we going to get the land? Well another topic that many people on this site like to push is how suburbia is doomed. However let's say half of suburbia was to die off, next thing you know land is cheap. So someone moves into suburbia and buys up three houses for dirt cheap suddenly there's enough space to grow vegetable crops. Enough to feed the farmer and sell the rest.

So now you have a dense urban center, surrounded by potential market gardening green space. Not to mention the infrastructure needed to provide water to this newly defined green space already exists. Add to that urban gardens and it gets better.

Even if the scenario above about suburbia doesn't come true. Why would we throw away hundreds of years of conventional wisdom on the subject of conventional farming and instead build an elaborate hydroponics system which is now more dependent than ever on the very systems that were the problem in the first place?

Isn't it easier to work with nature than to try and re-create it?

Hey, let's stop talking about it, just do it! The knowledge of the process, impacts, costs and benefits have been around for a long time. So, do it.
With regards to hydrophonics, the tomatoes are too watery, they don't taste as good as ground grown. It's the wrong crop for the right process in urban areas.

I agree with most of the above however, I see alot of people stating that the food produced on the rooftops etc would not feed everyone in the city well I think you also take into consideration that alot of people in the US, Canada and several other countries are obese often linked to inactivity, over-eating, and eating non-healthy fatty foods. Mainly because of the convenience of it. I think that the idea of growing fruits and vegetables in urban/suburdan landscapes such as rooftops is an excellent idea, but there are many other factors to be included i.e. weight load of a full crop with all factors including wet soil, getting more of the population to stop eating fast food products or to drop it by at least 50% and to eat healthy more often, furthermore we would need to retrain people to eat less but still get the proper nutrients. I think that alot of people eat so much more "food" because they are lacking the proper nutrients so there brains trigger their bodies to crave more food. There is so much junk out there. If you can tackle most these issues than i think that growing fruits and vegetables on rooftops etc. will work for at least 90% of the population.

Very unlikely we will see food towers when throwing up a 20x50 hoop house costs about $1000. As for the roof tops, it would be a nice place for roof top gardens of all sorts, kind of like private parks.

The reason people stopped farming is because it is hard work. People were encouraged to leave the farm and get a degree and a "good job" in the city.

The reason people stopped gardening is because it is easier and more amusing to flip on the tv.