Greens Infrastructure:
How urban farmers are cleaning urban environments by growing food
Here’s a fun fact. For about one-tenth the cost of a new playground you can create a green, busy, public place that can:
- Capture tens of thousands of gallons of stormwater (removing hundreds pounds of phosphorus from local waterways each year)
- Maintain the site at no cost to the public
- Feed hundreds of people a year (with very low carbon production)
And once this beautiful place is created on a derelict property, it can also teach young people fundamental work habits, and capture hundreds of pounds of carbon. These places are urban farms. There are about 12 of them in Boston, run by great groups like the Food Project and Revision Urban Farm.
For the last three years I’ve had the pleasure of working with the Urban Farming Institute, building new urban farms in the middle of Boston’s dense neighborhoods. The social impacts of urban farms like these are now more widely recognized, and research is now starting to assess the triple-bottom-line value to cities.
But despite this growing body of analysis urban agriculture is consistently questioned for its utility, especially in regards to its impact on local food systems. Those critics are addressing the wrong question. The question we should be asking ourselves is: “What interventions are the most cost-effective, when all benefits are measured, for addressing environmental problems in cities?”
Compared to the costs of creating other types green public places- parks, playgrounds, and green infrastructure/low-impact design construction- urban farms stand shoulder to shoulder as a good return-on-investment for solving cities’ environmental challenges. To demonstrate the comparative value of urban farms, consider the extent of some of the costs of the alternatives.
Stormwater:
According to a 2014 EPA study, 23,000 square feet of bio-retention and infiltration (aka an urban natural area) in Lancaster, PA avoided $749,000 of 25-year capital costs to the local water and sewer authority (e.g. energy or construction costs to contain and manage the polluted stormwater run-off from an urban site). Recent analysis by a leading local hydrology and engineering form confirm that Boston urban farms, as currently designed, match the performance in EPA’s results and reduce phosphorus discharge by 67% compared to a vacant lot. Crudely calculated then, a 10,000-square foot urban farm in Boston would avoid $325,000 over 25 years, or $13,000/yr, of investments in our over-taxed sewer system.
Interventions constructed to reduce this cost to ratepayers, can be expensive. Pervious pavers, for example, are popular solutions for capturing stormwater onsite while allowing for other uses like parking lots or sidewalks. Pervious pavers currently cost $10/square foot, or about $100,000 for a 10,000-square foot lot. Even the classic “vegetated swale,” a tried-and-true low-impact design around America’s roads and parking lots, costs $20/foot to construct.
An urban farm is an organic, productive sponge, designed to both absorb rainfall and keep root stock away from urban soils. When coupled with simple stormwater management best practices you can have the clean water impacts of this…
but with the added benefits of this…
Maintenance:
Compared to parks, or engineered solutions to stormwater pollution like pervious pavement, urban farms are a massive savings in O&M costs to city governments. Small neighborhood parks cost roughly $18,000/year to maintain. And urban planners advocate for parks departments to do more than cut the grass: effective public places need programming too which costs time and money to do well.
Also, pervious pavers and other stormwater designs must be maintained regularly for them to function well. Sweeping, vacuuming, and hand clearning pavers can cost thousands of dollars a year for 10,000 square feet.
Urban farms are maintained by the farmers, at no cost to anyone except their customers: their labor is paid for by the food they grow and sell. These beautiful sites are green and colorful all through the growing season at no cost to the city. And farmers run programming too. Like any shrewd modern farmer (e.g. pick-your-own orchards or farm stands), urban farmers actively engage their neighbors and volunteer groups by hosting field trips and work days.
So, you could spend public funds to maintain your pollution control like this…
or like this…
Food:
Urban farmers in Boston have learned how to farm very intensively, using season extenders and intensive soil and water management to coax the maximum amount of food from their 10,000-square foot farms. If Rutger’s recent study on the subject is a guide, a farm like Garrison Trotter Farm in Roxbury will grow over 5,000 pounds of food each year.
That yield is sold to pay for the farmers’ stewardship of the property so I won’t include the value of that here for fear of double counting. But there is evidence that suggests that exposure to local foods and their production improves eating habits, especially in food deserts. Quantifying health benefits from improved diets is a very tricky thing to do, however, so let’s just chalk this up as a general “good” for now.
Comparison Shopping:
An urban farm in Boston costs about $100,000 (plus staff costs). These costs provide due diligence on the vacant lot, engineering and design, permitting, site work, soil, water connection, and fencing.
This $100,000 outlay, then, is comparable to:
- Treating $13,000/yr of stormwater, or
- Paving property with pervious pavers, or
- Building one-tenth of a playground, or
- Creating one-half of a pocket park
There’s plenty of land to farm, even in densely developed cities like Boston. A 2014 study by Tufts University graduate students found that there were 717 city-owned large-lot (>10,000 square feet) vacant properties in Boston, totaling 564 acres. What we lack in Boston, however, is a wider public recognition of the comparative value of urban farms for tackling expensive problems. The City of Boston deserves credit for referring to urban farms as a climate smart solution in its Climate Action Plan. But unfortunately, when it comes to public investments, most agencies revert to old practices. Credit goes to the Massachusetts Department of Agricultural Resources for leading the way with their new Urban Agriculture Program; others should follow.
We still have a lot to learn about the values of urban farms in dense neighborhoods like Roxbury, Dorchester, and Mattapan. The benefits are so widespread, and touch on so many sectors- environment, community, beauty, economy, and public health — and at such a comparatively low cost, we shouldn’t need to measure every outcome before increasing our investment in greens infrastructure.
