If you ignore the nearby tops of buildings at eye level, you would think that these native plantings are on the ground.

Jim Mumford, owner of Good Earth Plants, is passionate about advocating the use of forward-thinking environmental designs for commercial and residential buildings. Although it is almost unheard of in Southern California, Jim has demonstrated how to create a green roof specifically designed for San Diego.

Green roofs are being considered to improve the environmental and energy performance of buildings. Jim has proven this with a savings of 23.5% on his SDG&E bill over the last year! In addition, the run-off from infrequent rain events has been reduced by 70% and is both slowed down and filtered of particulate matter. Green roofs have been used in Germany, Northern Europe and Japan for more than 30 years to help reduce the urban heat island effect and storm water run-off problems.

Project Info Project Management Todd Lass, General Manager, Good Earth Plants Architect Robert Thiele, architect with the American Institute of Architects Builder/roofing Ulf Waldman, Mission Valley Roofing Planting Mike Evans, Tree of Life Nursery; Chris Lyon, Planter Technology Modular Units Irrigation Bob Humphus, Greener Concepts Irrigation

However, installing a green roof is not for the faint of heart! This retrofit began with removing 10,000 pounds of the existing roof and a dozen penetrations. The new roof includes a PVC waterproof membrane, drainage layer, water retention mat and irrigation system. He then added custom growing media and several hundred plants. Green roofs have been installed on two of the four roof tops at Good Earth Plants and a small roof on a trade show exhibit is on display.

    Each building uses a different system, so Jim can compare their performance. The main building – which you will see on the tour – is a “built-up” system: a waterproof liner, like that used for ponds covers the entire roof, with 4 inches of growing media on top. Watering is done via low-water-use MP rotator sprinklers. Shallow native and alpine plants are chosen carefully for noninvasive roots, as shown in the photo.

A second rooftop has a modular planting system that uses 4’ x 2’ modular trays and in-line drip irrigation. In the future, a third building’s roof will be vegetated using pre-grown sedum mats and the fourth building will be kept as a control for evaluating the effectiveness of the green roofs.

Also, there are two different systems on display used to create “living walls”. Jim will continue monitoring both energy usage and storm water runoff for the green roofs and evaluate the plants, growing medium and irrigation systems for the best results.

Mumford has assembled a team that is critical to the success of any green roof project, including Ulf Waldmann, a roofer originally from Germany who has experience with green roof construction, and a Leadership in Energy and Robert Theile, an Environmental Design (LEED) Accredited Professional architect.

Come join Jim and his team for a scissor lift ride in the sky and see first hand the beauty and ingenuity of a green roof. Please dress appropriately.

A plant sale benefiting the Earth Works Foundation will be held In conjunction with the tour!

For more information about the Good Earth Plants “Green Roof project”, visit www.GreenRoofSanDiego.com.