Being a New York green contractor we consider urban farming to be an important consideration for every project. Given every building has walls and a roof it is always worth asking wither they are well suited for vertical or roof farming.

Sub-Irrigation Planting Systems (SIPs) are a perfectly sustainable answer to urban farming, according to Frieda Lim, creator of Slippery Slope Farm, a rooftop micro-garden in Brooklyn that utilizes this technology.  This is not your typical urban garden – the beds are portable for one, the plants are also healthier, they produce far more veggies per square foot and require up to 90% less water.  Pretty impressive for a garden that can be created in just about any outdoor space available, requiring very little green thumb and using virtually whatever containers you have available (salvaged wooden boxes, storage tubs, re-purposed soda bottles)
These benefits are all basically achieved by watering from below (hence sub-irrigation).  A water and air reservoir is contained at the bottom of each plant container, with the soil and actual plants suspended above.  The plants get their water through their roots, and the owner waters them through a “fill tube” which eliminates the waste of traditional top soil watering.

Want to get started on your own SIPs garden this spring?  Check out the website, http://www.slipperyslopefarm.us/index.html, where Frieda offers services for those who need help designing and constructing all types of sub-irrigation systems.  She also explains the methodology in more detail here: http://www.youtube.com/watch?v=el1tn0FpiVE

Happy Gardening!