'Green curtains' block heat, save energy

June 22nd, 2011 The Yomiuri Shimbun in Earth / Environment

A growing number of people are turning to nature to help them save electricity this summer, creating so-called green curtains of climbing plants.

According to the Energy Conservation Center, Japan, a key element in is reducing the use of air conditioners, which consume the most electricity in homes. A green curtain helps block the sun and keep room temperatures from rising through transpiration of the plant's leaves.

Green curtains can be easily set up at home, and Tokyo's Itabashi Ward Office has been promoting them as an effective way to battle global warming.

With power shortages expected this summer as a result of the crisis at the Fukushima No. 1 nuclear power plant, the ward office has received an increasing number of inquiries from local residents about growing green curtains.

It also received more than two applications for every spot available in a class organized by the ward office on how to grow a green curtain.

Likewise, Katsushika Ward of Tokyo distributed free goya bitter gourd seeds to residents in late April. All 500 packets were taken by the second day.

A Katsushika Ward official in charge of distributing the seeds said, "Interest is higher (in growing goya) than usual. Many people are trying to grow it for the first time."

Tsuneo Kobayashi of Itabashi Ward, 79, has grown goya since 2009. He said the plant can make a four-meter high and three-meter wide green curtain as its vines grow.

"The room with a green curtain is clearly cooler than one next to it, which gets direct sun," Kobayashi said. "Seeing green plants soothes me."

Plants suitable for making green curtains include goya, bottle gourd, morning glory and others.

Accordnig to Koichi Sugawara, secretary general of the Tokyo-based nonprofit organization Midori no Curtain Oendan (green curtain cheering squad): "You can save money on electricity by making green curtains, which also give you the joy of growing and harvesting something."

Ichiro Awano, public relations director of Sakata Seed Co. in Yokohama, recommended goya for green curtains because it is easy to grow. People who want to use planters should purchase one that can contain at least 36 liters of soil, Awano said.

Goya seedlings should be planted 20 centimeters apart in a planter filled with soil for growing vegetables. It is important to fix a garden net firmly under the eaves, which goya vines could twine around. A net with a mesh of 10 to 18 centimeters should be used, Awano said.

When goya has seven or eight mature leaves, the tip of its stem should be nipped off to help lateral buds grow. Provide additional fertilizer after goya begins bearing vegetables, he added.

"If you want to make a thick leafy curtain, you should give extra nitrogen fertilizer," Awano said. "But this will result in a slightly smaller harvest. Before you actually start, you should seek advice on how to grow seedlings at the garden shop where you purchase them."

(c) 2011, The Yomiuri Shimbun.
Distributed by McClatchy-Tribune Information Services.

"'Green curtains' block heat, save energy." June 22nd, 2011. http://phys.org/news/2011-06-green-curtains-block-energy.html