Rooftop Greenhouses in Manhattan: The journey is the reward

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After finishing up at Stone Barns in June, I was facing a 2 month gap before I was slated to head up north to work Four Seasons Farm in Maine, home of Eliot Coleman, Barbara Damrosch and their crew.   During a conversation and rooftop tour with Manhattan restauranteur Eli Zabar, I learned of his excitement regarding a new greenhouse project he was looking to build on one of his Vinegar Factory rooftops here in New York City  I had just spend a lot of time working in a unique and massive greenhouse up in Westchester, but I had yet to develop a greenhouse of my own.  Nevertheless, a little bit of faith from Eli and problem solving, for the last 8 weeks, I have been creating and developing...

the beautiful greenhouse pictured above.  Before leaving Stone Barns, my last greenhouse experience was assisting with the new high tunnels for summer field tomato production. these tunnels offered protection from hard rainfall which could lead to splashing of molds and other diseases that effect tomato plants left in the open. Also, the cover offers additional protection from harsh winds that can damage plants or even spread early and late blight.  

For Eli, I orginally wanted to replicate a smaller version of the engineering beauty that I had worked in at Stone Barns, but what I soon discovered was that large hard paneled polycarbonate structures like that are very expensive and there are many different, less expensive, but equally as effective options available such as the simplr high tunnel that uses common rail fence pipe and a long lasting double polyethylene cover.  

As with everything in life, each new challenge is a new puzzle to solve.  What we bring with us is the bag of "tools" we have been developing through all of our life experiences.  I had worked in greenhouses before, but I had never ordered one or installed a hydroponics production system, but using the basic principles of growing and some risk it all came together.   

After a lot of phone calls, internet research and questions, we finally settled on a design.  Using the high tunnel structure and some leg extenders, we were able to build a 12' x 48' greenhouse with 8' sidewalls. We extended the sidewalls to provide enough space between the hydroponic towers and the poly cover. If they are too close together, the heat will kill the top plants.  The construction team we worked with managed to creatively build and design additional supports that would usually be simply staked into the ground if this were on land. Using a two custom twisted metal "ropes," they anchored each side of the structure down to the oppoaite buildings. The additional overhead structure put in place to hold up each vertical tower also helped stabilize the greenhouse. Up here on the rooftop, there are a lot of different issues to contend with, i.e concrete, wind, other buildings and drainage etc.  All solutions, the construction team tirelessly uncovered.

After only a few days, the greenhouse was up and running, then the hydroponics system was to be installed. 

Using overhead metal supports that ran parallel to the greenhouse walls, we were able to fasten each hydroponic tower in place.  

A fairly simple system, Vertigro, the hydroponics company we worked with, sent us all the growing materials we needed for over 300 plants.  Eli wants to grow strawberries and herbs so we split production about 50/50. Using much less water than a traditional soil based growing system, each tower has one 1/8th inch micro tube that delivers a small stream of water to the top container, the system stays on delivering a mixture of water and dissolved nutrient solution as each pot drips through to the one below it. Eventually, when the final pot drips through, the water cycle is complete. This occurs 2 or 3 times a day based on the whether and plants you are growing.

The simple system includes, long-lasting styrofoam growing pots, growing media consisting of coconut fiber, course perlite and the Verti-gro proprietary nutrient solution which is used to feed the plants through a pump system placed in a simple 50 gallon garbage bin.  

I understand that coconut fiber is a waste product that retains a lot of moisture and perlite is used for drainage, but using a "nutrient solution" instead of amending soil is where I am not convinced that hydroponics is the best system. I believe that all the biological interaction that takes place in soil between the soil amendments and microbiology is what creates character, nutrition and flavor to your food and in a hydroponic system, this buffer does not exist.  All the nutrients are pumped directly to the plant roots in water.  Nevertheless, in major cities and other food deserts, we need to really think about innovative ways to produce food.  An incredibly interesting project, I am amazed that in such a short period of time everything was completed although it is unfortunate that I won't be there to see its development.

What was most intriguing about this opportunity to me was in such a short period of time I went from a place of complete darkness to light.  I had no knowledge or prior example of how to put this together, but through research, will and devotion, the project was completed and through all the mistakes, I learned a tremendous amount.  I can honestly say I still have no idea where all this is leading, if anywhere, but the journey continues to be life-changing and filled with learning experiences, exactly what I expected and hoped for.

The journey continues...