Urban Farmers Look Up To Compost

The Brooklyn Grange has a total of 2.5 acres under cultivation in New York City. Composting and compost use are integral to its operations.

Laura Rosenshine and Jillian Brooks
BioCycle October 2015, Vol. 56, No. 9, p. 47

In urban environments, growing food in healthy soils needs to go beyond efficiency to be effective. In New York City, agricultural entrepreneurs have been creative in their solutions for local, sustainable urban farming. One example is the Brooklyn Grange (BK Grange), which uses large-scale rooftop spaces to cultivate and experiment with farming. Five years into its venture, BK Grange operates two rooftop vegetable farms — a total of 2.5 acres. It grows 50 different kinds of produce, generating over 50,000 pounds of organically grown vegetables each year for local restaurants and farmers markets. The bulk of its crops are seasonal, however the farms are equipped with greenhouses and hoop houses to grow year round.

The idea for the urban farm started with a group of people involved in Eagle Street Rooftop Farm, a 6,000 sq. ft. rooftop in Brooklyn. Learning urban farming and business practices from the Eagle Street operation, in 2010, a team of five decided to begin their own venture. Knowing what to look for in a rooftop was half the battle, so the team worked with architects and structural engineers in their search. Looking through municipal filings from the city facilitated identifying rooftop spaces that could work, while a real estate agent assisted in securing a property. After rounds of inspections for safety, spacing on support beams, and load-bearing capacity, a reliable space was found for the first rooftop farm in Queens.

Composting Kicks In

The BK Grange one-acre rooftop farm opened in 2010. Sitting on top of the old Standard Motor Products building, built in 1919, the roof is solid concrete enforced by rebar. It is strong enough to withstand three times the weight of the 10 inches of soil and vegetation planted atop it, which adds nearly 50 lbs/sq. ft. when fully saturated. BK Grange immediately started composting its own organic residuals in a closed looped system. That compost was combined with purchased compost and a soil mix to create 720 cubic yards (cy) of greenroof blend. To procure more organics to compost, the farm began accepting materials from a variety of sources to produce the best mix of nutrients for the soil. Space for a 3-bin composting system was carved out on the rooftop.

In addition to getting organic materials such as food scraps from local businesses, BK Grange receives large quantities of wood chips from a local carpentry business. Mast Brothers Chocolate provides nitrogen-rich chocolate husks, known for holding moisture and suppressing weed growth. A café located in the building the farm sits on top of supplies leftover coffee grinds and vegetable scraps, while goat and sheep manure is collected from a local farm in Queens. Kensington Stables, just down the road, contributes its manure.

Established community composting organizations also got involved with BK Grange. The Western Queens Compost Initiative, now BIG!Compost, delivered hundreds of pounds of food scraps collected from city residents at the Sunnyside Market in Queens, opening the door for the BK Grange to become a Greenmarket partner. Needing a lot of compost to topdress the 43,000 sq. ft. of farm space, BK Grange knew the next farm had to factor in greater on-site solutions to achieve organic nutrient-rich soil.

Expanding Operations

In 2012, BK Grange began planning a second rooftop space. The second farm, located on a 65,000 sq. ft. rooftop plot (roughly 1.5 acres), is atop a 12-story building in the historic Brooklyn Navy Yard. The roof is covered by 10 to 12 inches of compost-rich Skyland Rooflite® Intensive Agricultural Blend, which has about 15 percent organic matter content. The rooftop features concrete slabs enforced with rebar.

The BK Grange initiated composting at the Navy Yard by collecting material from other tenants, accepting organics like coffee grounds and distillery bran. Because the farm needs a much greater volume of organics to meet its 40 cy of compost/acre goal, BK Grange contacted GrowNYC, a nonprofit in partnership with New York City that operates hundreds of Greenmarkets across the five boroughs (see “Greenmarkets Facilitate Food Scraps Diversion in NYC,” February 2014). Greenmarkets are currently the most common place for city residents to drop off their food scraps, and organizations like BK Grange volunteer to compost them. Nearly 4 tons of food scraps were sent to the BK Grange rooftops in their beginning stages.

To manage the influx of organics from the Greenmarket, BK Grange began composting in a windrow, turned monthly. In 2013, it started using an aerated static pile (ASP) system, turned by hand when necessary. Through a grant from the U.S. Department of Agriculture’s Sustainable Agriculture Research and Education program, the farm was able to hire a full-time employee to concentrate on composting and soil nutrition. The ASP system facilitated the types of organics that could be accepted and processed; it also improved compost quality. Organics from Navy Yard commercial tenants, GrowNYC Greenmarkets, and other local, small business partners are combined for processing. The ASP system spans across 96 sq. ft. of space on the roof at the Navy Yard; solar panels provide the majority of power needed to run the fans. The Brooklyn Grange now has two windrows on the Brooklyn Navy Yard rooftop, and one ASP system and a couple curing piles at the Queens farm location.

The next step lies in finding the right screen to facilitate blending finished compost with soil to create the growing medium. The farm currently uses a bicycle-powered sifter. It also has added chickens to both farms, which are fed with purchased grain, appropriate food scraps, and greens from the farm.

With steady and sustainable growth in mind, the Brooklyn Grange operates as a limited liability corporation with 11 employees between the two farms. It aims to produce enough compost to eventually supply other local, urban farmers and gardeners.

Laura Rosenshine and Jullian Brooks co-founded Common Ground Compost, an on-line resource to advance composting in New York City (www.commongroundcompost.com).

 

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