It really seems such a simple idea, but why hasn't this caught on in other cities? The Philadelphia Horticultural Society has a great program of 'popping up" gardens all over Philadelphia in abandoned and unused lots. This little garden has found a home this summer along Broad Street in Center City. With box truck beer and food stands, picnic tables and big shade trees, this green open space along a bustling downtown street will no doubt be a great place to grab lunch or stop to for a little respite. This is a great program that other cities should adopt to put to good use vacant parcels that would otherwise remain derelict, unsafe and unattractive. Recycled materials, old tables and chairs, donated and slightly damaged plant materials organized in interesting and innovative ways, these pop up gardens are inspirational additions to urban open space. Boston, need any interim green??