Choosing an Irrigation System

 

In order to make the smart roof deck garden as low maintenance as possible, we wanted to automate the watering process in some way by creating an irrigation system. With a little research we found many options:

  1. water the garden by hand
  2. use sprinklers
  3. use misters
  4. use self-watering planters
  5. use a dripline

We did not want to water the garden by hand since it is intended to be as automated as possible.  Self-watering planters cut down on the frequency that you need to water the plants by hand, but they would still require manual attention. That left us with three options. Sprinklers and misters are both wasteful when used for container gardens. Sprinklers also just look sloppy with extra hose running around and misters are not likely to work well on a windy roof top. For these reasons we settled on a dripline.

There are two kinds of driplines, on surface and subsurface. Both would work well, but we decided on a subsurface system because it is more visually appealing. The system attaches right to a garden hose and setup only requires threading some pipes and valves together. Two popular brands of dripline irrigation products are Netafim and Rainbird. We chose the Rain Bird XFS dripline for our project because of its flexibility, durability, even water distribution, and the Copper Shield technology that prevents roots from growing into the water emitter locations. To use and install the dripline, a few other components are needed:

  1. 3/4″ Hose Thread Anti Backup Valve
  2. 3/4 Inch Female Hose to Male Pipe Thread Adapter
  3. Solenoid Valve and Low Flow Pressure Regulator
  4. Filter
  5. 3/4 Inch Female Pipe Thread to 1/2 Inch Rain Bird Easy Fit Compression Fitting
  6. Air Release Valve
  7. Water Release Valve
  8. 1/2 Inch Elbow Joint

A low flow pressure regulator was chosen because standard flow rates create enough water flow to water an entire yard. Most of these parts can be purchased together directly from Rain Bird in a Low Flow Zone Control Kit.

Smart Green Roof Deck Garden

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Goal: Transform this empty roof deck into a smart green roof deck garden that provides tasty food and stormwater runoff benefits. Then share the process so other small building owners can do the same.

There are several incentives for commercial property owners to install green roofs such as tax credits and subsidies.  However, these incentives don’t exist for individual residential property owners in most locations due to the relative size of the rooftop, even though collectively the rooftops of residential buildings make up a significant portion of the impervious cover of the city.  If there were better resources on how to install green roofs, and a way to incentivize them, more homeowners could contribute to helping with stormwater runoff.

Philadelphia does provide generous incentives to utilize other stormwater management tools (rain barrels, de-paving and permeable pavers, downspout planters, and rain gardens) through a program called Rain Check, but green roofs just get a one-page website with some resource links.  That’s probably due to the relative complexity of a green roof and the variety of structures that exist in the area.  There are of course many companies that will install green roofs, but that might not be an option for everyone due to cost.  Additionally, there is no incentive to incur that cost besides helping with stormwater runoff.  We hypothesize that encouraging homeowners to install a smart green roof deck garden, versus a passive green roof, provides the incentives needed (e.g. edible plants, low maintenance) for homeowners to incur the expense, and the stormwater benefits are a natural byproduct.