Wednesday, February 2, 2011

Urban Farming Challenge #15

So, you want to start an urban farm?

You've found a level, accessible vacant lot that shows a lot of promise.  You start walking around it, and then you see this.  It's hard to grow vegetables where someone's driveway used to be.

You stick a spading fork in the ground, and it turns up eight inches of clayey subsoil--the topsoil was scraped off years ago when the neighborhood was being "developed."  It's hard to grow healthy vegetables when there aren't many nutrients in the soil.

Or maybe you're transplanting tomatoes.  You stick the shovel in the soil, step down, and "thud," you hit a big rock.  You start digging it out, and realize that it's a lot bigger than you thought it was.  You have it halfway out, and then you notice another rock...and another...and another.  It's hard for tomatoes to thrive on top of an old house's stone foundation.

Or maybe you're really thinking ahead.  You send some soil samples to the University of Massachusetts, and they come back with estimated lead levels of 900 ppm.  It's hard to sell vegetables to people when you fear that they may do them more harm than good.

Urban soils are one of the big challenges facing urban farmers, especially those farming "reclaimed" land in blighted neighborhoods.  On our urban farm, we're trying an experiment this year.  We have a new piece of land that has above-average urban soil, but there is a foundation of a building under the soil (the building was never completed, according to neighbors, and the foundation was simply buried in the soil).  Instead of tilling the ground and rooting out the foundation, we simply laid 3"-6" of compost on top of the soil and mulched it with an additional 6" of leaves.

This solves two problems: compost enriches the soil and helps mitigate the effects of (potentially) high metal content in the soil, and the no-till raised beds provide an extra layer of insulation between the crops and the rocks buried in the soil.

If you want to start or develop your urban farm, you will need to discover and address the challenges presented by your soil.

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