West Philadelphia pilot garden

Elderly residents sit on their front stoops watching tattooed hipsters peddle by on fixed-gear bikes.  This cultural juxtaposition runs rampant throughout West Philadelphia’s Cedar Park neighborhood, while grit and urban decay provide a strange sense of continuity form one block to the next.

Lightweight soil mixing || photo by Lauren Mandel

One row house is different from the rest, although you would never guess it when looking from the street.  This two-story building is home to a rooftop gardening pilot project, built by a local group called the Philadelphia Rooftop Farm (PRooF).  PRooF volunteers gathered on the roof this past Sunday to bring a spark of green to the neighborhood.

The goal: to build two vegetable planters (out of a series of four), each measuring 3′ x 3′.  The volunteers first inserted corrugated plastic foundation containers into a wood frame, which they had previously built.  Next, they installed a plastic drainage layer, two layers of separation fabric, and planting soil.  One volunteer looked up several soil recipes on her iPhone, and the group decided to vary the mix in each planter in order to see which blend yields the healthiest crops.  After laying the soil, the volunteers covered the planters with black plastic, in order slow desiccation (soil drying) and stifle weed growth.  They slit the plastic and planted a variety of seedlings, including lettuces, chard, cucumbers, eggplant, and herbs.

Separation fabric installation || photo by Lauren Mandel

The planter design was a long time in the making.  Back in 2010, PRooF worked with a team of volunteer design and engineering professionals from the Community Design Collaborative (CDC) to further the group’s rooftop planter vision.  The final CDC design combined base irrigation techniques that are common in Canadian rooftop planting bins, with wood framing construction, which is more typical of raised beds.  The hybrid proved easy to install, and was made, in part, of salvaged materials.

Soil installation || photo by Lauren Mandel

PRooF’s plans for rooftop greening extend beyond this first installation.  The active group intends on evaluating the performance of the West Philadelphia pilot project, and then building more planters around the city.  Home owners are welcome to volunteer their roofs to the group, along with a commitment to water and occasionally tend to the crops.  It is important that each roof is structurally sound enough to bear the weight of the planter, although the CDC design included a strategy for distributing the planter’s weight across a row home’s party walls.

This is an exciting time for rooftop gardening in Philadelphia.  Thanks to organizations like PRooF, we finally have the “proof” that rooftop gardening on Philly row homes is easy!

harden off those youngins


Greenhouse seedlings at SHARE Food Program || photo by Lauren Mandel

With spring upon us, greenhouses across the country are full of eager seedlings.  Sheltered greenhouse environments are ideal for sprouting seeds and providing a head start for young veggies, but the real growing occurs outdoors.

Before transplanting seedlings to nearby raised beds and agricultural plots, the youngins need to be “hardened off.”  This involves acclimatising the seedlings to the sun, wind, and variable temperatures they will experience outside.  Farmers have different strategies for hardening off their plants, which usually involves introducing seedlings to the elements gradually.  Farmers may move young plants in and out of a greenhouse, leaving the seedlings outdoors for longer periods each day.  This gradual introduction often lasts for one to two weeks.

When moving seedlings to rooftops, extra care must be taken in hardening off the plants.  As discussed in earlier posts, rooftop environments are much more extreme than their ground-level counterparts.  Skyline farms and gardens are prone to high winds, desiccation (soil drying), and fluctuating temperatures.  So what does this mean for the hardening off process?  Well, the plants should probably be exposed to stronger elements.  This could mean leaving them outside on a particularly cold and windy night, or even bringing them up to the roof for short periods before transplanting.

Anticipating scenarios such as hardening off can help to inform the design of a rooftop farm or garden.  Enough foresight could lead to the construction of a sheltered rooftop area, designed specifically for acclimatizing seedlings.

What techniques do you use to harden off your youngins?

the hottest of hotspots

If the U.S. were a cupcake, and the rooftop farms and gardens dotted around the country were the sprinkles, then Brooklyn would be the cherry on top.  Thank you for bearing with me on that analogy.

Greenpoint, Brooklyn || Image by Google Earth

It’s true, though.  Brooklyn currently houses several of the country’s most innovative and inspiring rooftop farmsGotham Greens, a 15,000 square foot (0.3 acre) commercial greenhouse operation in Brooklyn’s Greenpoint neighborhood, leads New York City in rooftop yields.  With high-end distribution channels and a solid business model, the success of this rooftop pioneer may be inspiring other entrepreneurs to follow suit.  Eagle Street Rooftop Farm is another critical piece of the cherry.  As the country’s first rooftop row farm, Eagle Street Rooftop Farm plays an important role in building community and demonstrating farming techniques.  With a picturesque backdrop, this farm is arguably Brooklyn’s “greenest” icon.  Brooklyn Grange, while not actually located in Brooklyn, contributes to the local skyline network as well.  Ben Flanner, founder of Brooklyn Grange, co-founded Eagle Street and then spread his seeds of knowledge to the Grange’s rooftop in Queens.

It is with this proliferation and contagious behavior that Brooklyn is booming – I mean, blooming!  The New York Times reports that Gotham Greens is scheduled to open three new rooftop greenhouse operations in 2013, totalling 180,000 square feet (4.1 acres).  Brooklyn Grange is also expanding, and construction of the farm’s new 45,000 square foot (1 acre) location could begin as early as spring of 2012.

Then there’s the Sunset Park Greenhouse.  Brooklyn residents should expect to see this 100,000 square foot (2.3 acre) hydroponic operation atop a former Naval warehouse in the not-too-distant future.  According to the New York Times, the project’s greenhouse development company, BrightFarms, anticipates that the farm will produce 1 million pounds of food per year.

With agro-icons and big projects in the pipeline, Brooklyn is hot hot hot.

fishy business

Aquaponics || photo by Lauren Mandel

Does all this talk about lettuce and broccoli make you hungry for some real meat? Let’s talk aquaponics.

For centuries, people around the world have raised fish as a food crop. This cultivation occurs in ocean pens, large outdoor tanks, or sometimes in small tanks within greenhouses, in basements, and on roofs. A variant of the latter practice is called aquaponics.

Aquaponics is the symbiotic production of plants and aquatic animals in a closed-loop environment. This means that vegetables and herbs are grown hydroponically, while fish or other sea creatures occupy the water that fuels the hydroponic system. The symbiotic part of the relationship comes into play when the animal waste (fecal matter, excess food, etc.) is used as the sole nutrient source for the food crops, and in exchange, the plants filter the water for the fish. The clean water is pumped back into the hydroponic system, and the cycle continues – what a beautiful thing.

Bony fish (such as Tilapia and Perch), molluscs, and crustaceans are the most common aquatic animals cultivated in these systems. Variations in organism growth rates, compounded by the need for equipment adjustments, means that it can take up to six months for an aquaponics system to become fully operational. The Milwaukee-based agricultural organization Growing Power experiments extensively with aquaponics. Growing Power’s fish are sold to restaurants, direct customers, and ethnic markets.

While aquaponics is relatively new to the U.S., the technique has been practiced in Asia for many years. The concept of integrating farming with fish production is rooted in Asian tradition, and historic evidence suggests that this type of integrated farming may have existed 3,000 years ago in China.

3… 2… 1… action!

Australian film crew at Eagle Street Rooftop Farm || photo by Lauren Mandel

While standing in the spotlight may be uncomfortable at times, the strategic rooftop farmer embraces the media and “eats up” it’s marketing potential.  Simply put, media coverage can be instrumental in disseminating a farm’s brand.  Print and broadcast media coverage can go a long way, and social media may go even further within certain demographics.  Regardless of whether a newspaper journalist, cinematographer, or blogger visits your rooftop farm, it will behoove you to be accommodating and put your best foot forward.  The media’s relationship with a rooftop farmer, as with any public figure, can be either helpful or harmful in building the farm’s reputation, so be prepared!

Over the past few years, Trey Flemming from Urban Apiaries has learned how positive media relations can go a long way.  Trey and his urban honeybees often appear in magazine and newspaper articles around Philadelphia, as well as in online articles, blogs, and documentaries.  With all the attention, the Urban Apiaries brand has reached new heights: corporate America.  While once available only at local co-ops and specialty stores, Trey’s honey is now available at Terrain – Urban Outfitter’s garden center.

Annie Novak, from Eagle Street Rooftop Farm, similarly embraces media coverage.  When I visited Eagle Street Rooftop Farm in 2011, Annie welcomed me to the roof while in the middle of a photo shoot on the other side of a kale patch.  With a warm air and magnetic disposition, it was no wonder that Annie simultaneously engaged a film crew, a foreign journalist, and myself (the aspiring author).

Annie welcomed each person to the roof with the same friendly smile, before she figured out who they were.  Just remember, out on a roof you never know to whom you may be speaking.

a retrofit, retrofit?

In the green roofing world we recognize two types of green roofs: those built on new construction, and those built atop existing buildings. The latter is known as a “retrofit.” When considering a retrofit, a structural engineer must confirm that the building is strong enough to support a green roof, and a waterproofing representative must evaluate the roof’s existing waterproofing membrane. If all the stars align, then the retrofit is a go!

3"-thick green roof retrofit || photo courtesy of Roofmeadow

So can a retrofit green roof be retrofit with a rooftop farm? I had never considered this scenario until several weeks ago, when a repeat client of my firm, Roofmeadow, approached us with the question. We designed and built a 13,000 (0.3 acre) green roof for this client in 2007, on top of his factory in NJ. The 3″-thick green roof continues to manage stormwater and perform beautifully, but now the client is looking for more. He wants to grow food on his roof in order to sell to local restaurants and markets.

Luckily, this particular green roof will be easy to retrofit. Green roof systems contain various types of drainage layers, depending on the particular needs of each project. Some drainage layers are made of granular material, while others consist of synthetic sheeting (i.e. plastic peg sheets, egg crates, or tangled filaments). One drainage layer on the market is made out of foam scraps that are salvaged from car seat manufacturing, and bonded together to form a thick mat. In addition to managing the flow of stormwater and retaining water for plants, this multi-purpose layer can protect the waterproofing membrane from shovels and hoes when used in a rooftop farm buildup. Luckily, the green roof in question contains this type of drainage layer.

When retrofitting a green roof such as this with a row farm, the strategy would involve peeling back the top layers of the system to expose the foam drainage layer. Additional green roof media would be brought to the site and mixed with the existing media to create a deeper system. While the existing media contains a very low organic content (4%-6%), the new media would contain more organics to appease the veggies-to-be. Next would come grading, laying out irrigation lines, and planting, and then vwalah – rooftop farm.

Not every retrofit retrofit would be this simple. Nevertheless, there is always a way to figure out a solution, so go ahead and dig in.

the buzz.

If you mentioned rooftop farming a few years ago, most people would think you were crazy.  But now that rooftop farms and gardens have taken root across the country, more and more people are joining the conversation.  Groups like Cloud 9 Rooftop Farmthe Philadelphia Rooftop Farm (PRooF)NYC Rooftop Farm Initiative, and FarmRoof are talking the talk, and some are just beginning to walk the talk.

Rooftop place-making || photo and rendering by Lauren Mandel

Historically, aspiring rooftop farmers in the U.S. had to seek out rooftops and convince building owners to let the space.  Now, business owners in Philadelphia and New York City are elevating the buzz to new heights by planning for their own rooftop farms.  As the Rooftop Agriculture Specialist at Roofmeadow, I’ve spoken with several of these business owners during the past few weeks.  The prospective projects range in scale from 2,000 square feet (0.05 acre) to 66,000 square feet (1.5 acres), and include row farming and raised beds.  One prospective client even requested rooftop chickens!

Each business owner is interested in rooftop agriculture for a different reason.  Some value the marketing potential of a rooftop farm, others are interested in managing stormwater, and others want to supplement their commercial kitchens with roof-grown food.  Regardless of intent, the rooftop agricultural buzz is growing.  It’s growing all around the country, and it’s going to be big.

who are these people, anyway?

Rooftop farms and gardens are sprouting up in cities across the country.  Restaurants, community groups, families, and individuals are enjoying the bounty, but who the heck is up there growing all this food?

Volunteer at Eagle Street Rooftop Farm (Brooklyn, NY) || photo by Lauren Mandel

Lots of people – that’s who!  People of all different ages and ethnicities, with different skill sets, and different reasons for growing food.  American rooftop farmers tend to be between the ages of 22 and 55, with men and women equally engaged.  Most, if not all of these farmers migrated to rooftops from ground-level farms.  Some came from urban farms, and others from more traditional rural farmsteads.  Farmers who land these highly-prized rooftop positions are generally very knowledgeable about their agrarian genre – whether it be row farming, beekeeping, or hydroponics.  It is rare that a newbie finds himself in charge of much on the skyline.

Trey Flemming of Urban Apiaries (Philadelphia, PA) || photo by Lauren Mandel

Farm interns are a pillar of small agrarian farms.  In this young industry, however, formal trainees are few and far between.  The rare rooftop farm intern generally falls on the younger end of the spectrum, and carries her position for one to two growing seasons.

Volunteers, on the other hand, are key players in most rooftop endeavours.  These are the passionate folks who lend their time and energy in exchange for the experience alone, and maybe some fresh veggies on the side.  Farm volunteers are sometimes much younger or older than typical rooftop occupants.  They may enter the roof from a marginalized, inner-city neighborhood, or form another unsuspecting environment.

Vincent Dessberg of I Grow My Own Veggies (Sarasota, FL) || photo by Lauren Mandel

Laborers are common in large-scale, high-yield commercial farms.  Hydroponic facilities like Gotham Greens are structured to support a crop of highly-trained workers.  The pulse of rural farms across the country relies on migrant labor.  By contrast, the high-profile nature of rooftop farms tends to attract a very different workforce.  At this point in the fledgling industry’s development, commercial hydroponic farms are the only type of rooftop farm that can afford to pay workers aside from the farmer.  Perhaps this will change as the industry becomes more established.

We’ve now covered the key farming players, but what about rooftop gardening?  By 2009, the National Gardening Association found that 50% of American households grew some portion of their own food.  This astounding statistic means that anyone can be a rooftop gardener!  What’s your story?  Tell us about your own rooftop gardening experience, and you could land yourself  in one of the Eat Up volumes.