Lighter pots
Park Lane by CMP took a different approach.
"Taiwan's climate, its earthquakes, and the weight of the plants were important considerations during the design and engineering phases," says Huang Bozheng, chief engineer with Gabriella International Co., which handled the engineering of the wall. Huang says that the plants in the Park Lane wall are also grown without soil, but in non-woven-fabric pots (80 x 50 x 25 cm) containing a lightweight perlite, mica, and peat moss medium. The construction process involved first mounting a steel frame to the wall, then securing the pots in the frame. The company also installed some 3,000 meters of irrigation tubing, 6,000 drip-irrigation pipes, and several hundred mist nozzles beneath the frame.
The 140,000 plants in 3,260 pots weighing 30 kilograms each were cultivated for three months at a nursery in Tianwei Township, Changhua County before being installed in the wall with a crane. The entire process took four months.
The engineering team had to deal with different sets of considerations for the interior and exterior installations at Park Lane. Exterior concerns focused on issues such as wind direction, sunlight, and rain. In the run-up to last year's typhoon season, the team was very concerned about strong winds and heavy rains and prepared nylon windscreens that looked like mosquito netting. But Huang worried that the screen itself might damage the plants. If it weren't hung tightly enough, strong winds might cause it to batter the plants. Fortunately, he had made arrangements for the leaves to be gradually trimmed back from 80 cm to just 30 cm in length one month prior to the start of the season. This lightened the plants considerably, making the screen unnecessary.
Issues facing the interior wall included isolation from the weather and a lack of natural light, which meant that the builders had to provide both water and lighting.
"The shopping mall is air-conditioned all day and gets no sunlight," says Ho Pei-fen, spokesperson for the CMP Group. "So we installed 32 500-watt grow lamps. But we spent a lot of time figuring out how to set up lamps so that their light fell evenly onto all 10,000 plants. Even shade-tolerant plants are very sensitive to light. But sometimes we got the lamps angled appropriately for the plants only to discover that they were shining right into customers' eyes. We spent a very long time adjusting the angle of those 32 lamps."
Next, the team built a pool at the foot of the living wall and installed three upward-blowing fans to circulate moisture and raise the interior humidity. Ho says that the fans also make the leaves sway, which keeps them a brilliant green by helping them shake off dust.
Interior gardens offer a great many benefits. Indoor plants remove formaldehyde, benzene and other toxins from the air, reduce interior temperatures, and absorb dust from the air. Working in a pretty, plant-filled environment also keeps people alert and in a good mood. So how much does a vertical garden cost?
Ho says that companies tend to prefer to cut costs where they can and mistakenly see going green as an unnecessary expense. But after winning the Prix d'Excellence, CMP discovered that Park Lane had not only improved their corporate image, but also helped the company save energy and reduce carbon emissions. Putting plants indoors has cooled the mall, so the air-conditioning system doesn't have to work as hard. When you consider CMP's estimate that the plants cut the mall's monthly power consumption by 30%, the NT$20 million the company spent to build the wall (roughly NT$10,000 per square meter) and the NT$1 million it spends annually to maintain it look like good investments.
The exterior vertical garden at Park Lane by CMP covers an area equivalent to that of Taipei's Yongkang Park and absorbs roughly 200 kilograms of CO2 every day. People visit often to take photos of the brilliant green wall.