|By MICHELE F. MIHALJEVICH
FORT WAYNE, Ind. — The first thing visitors probably notice about one of the newest gardens around the Allen County Cooperative Extension Service building is that it’s in an unusual position.
“People are used to looking down to see a garden,” said Ricky Kemery, extension educator for horticulture. “We have to train them to look up.”
When they do look up, visitors are treated to a rooftop garden, which sits atop a small storage building behind the extension office building.
Rooftop gardens are popular in Europe and are becoming more popular in the United States, Kemery said.
“People who have seen it think it’s an innovative idea, and that’s our purpose, to show people what that style of garden is, and the benefits of it.
“It’s sustainable, helps keep heating and cooling costs down, and is perfect in a commercial or residential setting,” he said.
Kemery asked volunteers in the advanced master gardener program to research the idea of a rooftop garden a couple of years ago. It was constructed in 2004, and first planted last year.
Construction took awhile because the building chosen to house the rooftop garden had to be reinforced, said Darlene Degener, an advanced master gardener.
“You should talk to a builder before you do anything,” she said. “Even though the soil is not thick, and we use lightweight materials, it’s still heavy and you need to be sure the building is strong enough to hold it. You don’t want it to fall in.”
Once the building was reinforced, a layer of rubber was laid over the plywood base of the roof to help keep moisture away from the building, Degener said. The edge of the roof was edged with 2 x 4 lumber to prevent the materials from slipping.
Next a layer of capillary cloth was used to help distribute rainwater evenly, and a water permeable material was used to help keep the capillary cloth from becoming clogged.
A grid of PVC piping was used to keep the layers and plant materials from shifting or washing off the roof. A drain was installed to carry away excess rainwater.
A lightweight soil-less mix was combined with Perlite and the frame filled four inches deep. Finally, a plastic snow fence holds the plants and planting medium in place.
Plants used in the rooftop garden were sedums and succulents, Degener said. A pre-emergent is used to help keep weeds to a minimum.
“We wanted things that do well in dry weather,” she said. “Basically, these are things you might see in a rock garden.”
Coleus was planted as a moisture meter, she said.
Not only is the rooftop garden visually appealing, but it can help in other ways, too, said Nancy Firth, an advanced master gardener.
“It’s good for the environment, and helps keep you cooler in the summer,” she said. “The more you can green an area, the better it is for everything, including birds.”
An outbuilding on a farm would be perfect for a rooftop garden, Degener said.
“Once you get the building reinforced, the structure built and the plants in, the goal is to not have to do a lot of additional maintenance,” she said. “You can pick plants that do well in drier weather and that don’t require much maintenance.”
Rooftop gardens may also be used on commercial buildings to add green space. The largest such garden, at 10.4 acres, is on the Rouge facility of the Ford Motor Company in Dearborn, Michigan, according to the magazine, Garden Design.
Europeans have become used to seeing rooftop gardens of all sizes, said Barbara Gibson, an advanced master gardener.
“It’s not uncommon for them to see these,” she said. “They’re not the surprise element that we have here. But they’re an environmentally friendly project and add a lot.”
This farm news was published in the June 28, 2006 issue of Farm World, serving Indiana, Ohio, Illinois, Kentucky, Michigan and Tennessee.