By KAREN BINDER
Illinois Correspondent

CARBONDALE, Ill. — The College of Agricultural Sciences Building on the Southern Illinois University Carbondale campus is green in more than one way.

Students have been working on what they fondly call the “green roof project” since Sept. 20. This work requires that they climb and plant wildflowers and grasses on the roof of the Agriculture Building, said Sarah Stack, a senior from Frankfort, Ill., studying plant and soil science.

The project not only adds a living aesthetic to the building, it also is expected to reduce energy costs by providing extra insulation to the roof. This is the first building with a green roof on the Carbondale campus, but more are planned.

The project is funded by a $20,000 grant fed by the university’s current $10 per semester green student fee, as well as $10,000 contributions from the College of Agricultural Sciences dean and the Physical Plant budget, said Karen Midden, professor of agriculture.
The green roof is both educational and economical, she said. One section of the roof was left unplanted for research purposes for graduate students, she explained, adding that “I wanted students to have a demonstration green roof as a studying tool.”

This study site also provides actual roof conditions to conduct research on plant selection, growth media formulation and fertilization options.

Various species are being evaluated for drought tolerance, winter interest, sunlight requirements and other considerations that affect green roof suitability.

Besides that, growth media formulations, including expanded clay, expanded slate, lava rock and pumice are being evaluated for rooftop suitability. The research team is studying the performance of several fertilizers and the possible leaching associated with each strategy, Midden said.

The goal of this research is to establish tolerance thresholds for stress and to identify plant species suitable for green roof propagation. Midden said she hopes the green roof helps attract students to the university because it offers hands-on research opportunities.

“We learn by action,” she said. “When you’re out in the field, you’ll already have had some of that experience.”

Eventually, Midden said the project will be easy to maintain. “All of this will self-seed,” she said. “Once it’s established and grows pretty closely together, it won’t be very high-maintenance.”
Forestry student Thomas Day pointed out the project provides research opportunities and cuts down on electricity bills for the building.

Thomas Cooper, managing director for Green Roof Solutions in Chicago, said savings vary depending on the building’s layout. He said the difference between a bare roof and a green roof is the amount of ultraviolet rays absorbed into the building.

“Without plant life, the sun is being absorbed more, making it more expensive to cool the space below,” he said.