How to Grow Your Plants in an Urban Setting

Although the title might imply that someone is making the transition from youthfulness or adolescence into the wonderful world of adulthood — and doing so while living within a metropolis — this article has nothing to do with people growing older or being urbanized.

What it refers to is the concept of growing your plants upwards.

When your growing area is cheap, you grow acreage of commercial vegetable crops outside on sprawling land. This is the rural farm model that has worked since the beginning of this country.

As land gets more expensive, growers use the best horticultural techniques available to squeeze more value out of those acres. This includes things like plastic mulch, drip irrigation, row covers, high tunnels, and other things you read about in American Vegetable Grower every month.

This resembles the farms that are more in suburban areas, or at least the rural — suburban interface. Taxes are higher, living expenses are higher, and more income is needed to cover higher fixed costs than in rural areas.

Now, suppose you want to grow in urban areas, like medium-sized and large cities. The typical response is to grow in the rural or suburban areas and truck the produce in to your markets. Isn’t that how it has always been?

Times may be changing. A growing segment of the population is “green” conscious. Being green is clearly to the benefit of everybody — the consumer, the wholesaler, the retailer, and the producer.

Urban Farming
To be green in the urban setting, people are becoming aware of how far the produce travels before it gets to their stores. The figures being thrown around in the media vary, but let’s just use 1,500 miles for average produce items.

The more “frequent flyer” miles our vegetables accumulate, the more fuel is burned to get them to us and the larger the carbon footprint. If only the food could be grown within the urban setting, within a few miles of its final destination.

But wait, there’s more. Some of the catch phrases being thrown around are “urban farming,” “vertical farming,” and even “skyscraper farms.” All of these are linked together by the concept of raising crops inside large buildings within cities, stacking crops vertically, to fit as much as possible not only within the walls, but also between floor and roof. The production per square foot would be phenomenal, theoretically.

Urban farming would decrease the miles traveled from more than a thousand to just a few. And, it would drop the carbon footprint to virtually zero, theoretically.

Huge, new structures would be built in the largest cities. They would either be all glass to allow as much light in as possible, or they would have thousands of HID (high intensity) lamps on every floor to ensure maximum photosynthesis and productivity. These would be a model of sustainability and a prime example of being green, theoretically.

The skyscrapers would need to be heated to 70° or 80°F to suit the production regime of tomatoes and other warm weather crops. Lower temperature could be used for lettuce and other hardier crops. Solar panels could be installed to generate “free heat” to these crops, theoretically.

Water savings would be phenomenal. The same water used to irrigate these crops could be recycled and pumped back for reuse indefinitely. Well, it’s a theory.

Weighing Costs And Benefits
I’m not a total skeptic. There would clearly be lots of benefits to growing all of the food that city people need within a few blocks of their high rise condominiums, brownstones, or townhouses. Fresher food, locally grown, etc. is very appealing.

I am, however, at least a little cautious about total immersion from growing our crops in the earth or even hydroponically in traditional greenhouses to raising them in downtown skyscrapers just yet. Here are seven areas of concern:

1. The buildings would be very expensive to build, to heat, to maintain. For solar energy to work there would have to be millions of square feet of solar collectors to generate enough heat and electricity to light a skyscraper full of crops.

2. It takes a lot of heat to keep a crop healthy during the long winter months. Unfortunately, most of the large cities in the U.S. are in the northern latitudes with long, cold winters. Maybe that’s why most of the new greenhouse construction in recent years has been in the southern U.S. Perhaps Atlanta, Dallas, or New Orleans would be better candidate cities than Chicago and New York.

3. Water could be recycled. But, it needs to be sanitized so that pathogens are not spread throughout the crop. There are ozone and ultraviolet technologies that can work, but these are also expensive. Furthermore, plants use nutrients from the nutrient solution that is pumped to the root systems. The solution would need to be continually monitored to determine how much of each nutrient needs to be added to the recycled water to bring it back up to the level that plants require.

4. Crops need light. If the entire structure is glass, the natural (free) light would be maximized. However, there would only be enough light along the outside walls and the top floor of the skyscrapers. Most of the crops would be too far from these walls or the top floor to survive, let alone produce. So, if solar is too expensive, then HID lamps could be installed. These are also very expensive to buy, but especially to operate, and it is certainly not green to have a huge electric bill.

5. Although the travel miles could be reduced, the carbon footprint would not approach zero. The construction inputs and power needed for these urban crops would be very high.

6. What about disease and pest management? Would we use chemicals in the urban landscape, or try to grow everything organically?

7. The concept of urban farming is, well, fascinating. I just think we still have a lot of logistics to discuss before assuming that this is the way of the future.