Time to begin. In early September I approached Jonathan Youtt at the PLACE for sustainable living in Oakland, Ca. to ask if he had a space for us to test our system out. Our Berkeley project was being delayed and I wanted to keep TJ busy and use the extra time to learn more about the design we were to install on the 16 roofs. Alot has been tweaked on paper and it was time to begin testing it out. We also switched blenders and wanted to start growing in the new medium we had developed.
The space that we were given was the roof of two shipping containers that were 20' long. The space ended up being 276 square feet, after we built the deck and parapet to contain the soil. There was alot of ideas that had been floating around in my head over the last 6 months on how to make a more productive lightweight and affordable system, getting the opportunity to do a test run at PLACE has been invaluable.
Once we got the deck built and set we installed the irrigation system which included a mazzi injector for fertigation trials which will help us understand which driptape and irrigation lines work the best.
Next step was to line the area using a poly re-enforced 40 mill liner with protection mat. We used a drainboard on half the deck to see what the difference will be like with and without. Each side will have wicking capabilities just a matter if the drainboard cups will retain more moisture and allow for better airflow through the bottom.
Then came the medium! Two different mixes, 4" of a wicking layer and 8" of a growing medium that we have designed custom for our system. We used American Soil and Stone mostly because their yard is less than 1.5 miles away! 10 yards total material. Decided to get a forklift to get it up off the ground and onto the roof.
Benjamin Fahrer is the owner and operator of Top Leaf Farms and has over 18 years of organic farming experience, building, design work and teaching in natural resource management.