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Originally published August 12, 2012 at 5:30 AM | Page modified August 13, 2012 at 7:12 AM

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Volunteer Park Conservatory at 100: Take a tour with the senior gardener

Seattle's Volunteer Park Conservatory turns 100 this summer, and one of the biggest changes over the years is one you can't see: Technology now regulates heating and cooling of the glass house. Senior gardener David Helgeson and his compatriots now can spend their workdays working on the plants.

Seattle Times arts writer


Volunteer Park Conservatory may be celebrating its 100th anniversary this weekend, but behind its Edwardian veneer, it's definitely a creature of the computer age.

A tour behind the scenes with David Helgeson, senior gardener for the last four years, makes clear how much the place's greenhouse technology has changed in the past two decades.

When Helgeson first started working there 25 years ago, the conservatory and its support greenhouses were entirely manually operated. That required a full-time staff working in shifts, 24 hours a day, 365 days a year, operating the vents and the heating system.

Helgeson was on the graveyard shift himself in his early days, walking through the buildings, taking hourly temperature readings in each part of the conservatory and the support greenhouses, and adjusting the vents and heat valves accordingly.

In the now-closed east support greenhouse, built in 1922, he pulls a squeaky, hand-cranked chain, showing how the vents used to be opened. The rickety sound and the sight of the greenhouse itself, where nature is avidly restaking its claim, feel like a scene out of a Tim Burton movie.

Then, with a short walk, he brings you into the modern era. The west support greenhouse, built in 2006, incorporates Dutch Venlo technology which, Helgeson says, is "pretty much the industry standard for greenhouses nowadays."

It's taller than the old greenhouses were, he notes, so as to support all the gear that hangs above the plants. That gear includes a shade cloth that can be programmed to advance over the plants, lengthening their "nights" in summertime. Auxiliary lights can likewise lengthen their "days" in winter. Hi-tech Mylar woven fabric overhead, reflecting about 55 percent of the light back out into the atmosphere, keeps the building nice and cool this time of year.

Helgeson points toward the glass ceiling, where a white apparatus is suspended that looks like a cross between a microphone, a small speaker and a security camera.

"There's the sensor that talks to the computer," he says. "It's a pretty sophisticated software program. You set the temperature and humidity values for each zone or each room, and the computer, when it's working properly, takes care of regulating all those."

Each section of the greenhouse can be calibrated to make the plants do what the gardeners want them to do. Chrysanthemums, for instance, take their cue to bloom from being exposed to shorter daylight. Right now in the support greenhouses, one long row of chrysanthemums is in a dormant state, while another, artificially shaded, is enjoying a growth spurt.

"Starting in about mid-September, all the way through November," Helgeson says, "we'll have a succession about every three weeks of a new batch of chrysanthemums."

The need for automation was triggered, in part, by budget cuts in the 1990s, which led to the elimination of three staff positions. (The conservatory now has four full-time employees, and one temporary half-time employee.)

With the computer monitoring and regulating conditions, gardeners have a lot more time to get actual gardening done. The downside is that when the computer malfunctions, it's often beyond the scope of the gardeners to fix it.

"It's a problem when it's 90 degrees and the vents won't open, or it's 30 degrees outside and I can't get the heat on," Helgeson says. "You sort of wish you could just go turn a valve."

All the plants in the conservatory are grown on-site, most of them from cuttings. In fact, until the early 1990s, Volunteer Park Conservatory supplied the annuals for the entire city park system. These days Seattle Parks and Recreation's Jefferson Greenhouse on Beacon Hill supplies the park system's ever-expanding needs.

Like most conservatories around the country, Volunteer Park has steered away from using pesticides.

"The basic concept is that you're using Mother Nature's techniques," Helgeson says. Predators targeted to specific pest insects are released regularly "to do what they do, so we don't have to rely on heavy chemicals."

Conservation is a central focus of the conservatory. One form this takes is the conservatory's function as a "rescue" site for endangered orchids, cactuses and succulents confiscated because they violate import/export laws under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

"We receive, usually once or twice a year, shipments of plants from the CITES folks," Helgeson says. Many of those plants, he adds, no longer have intact habitat in their native environment. The conservatory's rescue efforts may help preserve them from extinction.

The heating plant that creates the custom-tailored conditions for different sorts of plants has been through considerable changes of its own over the last 100 years. Initially, the boilers were coal-fired. A switch to No. 2 diesel fuel lasted through the 1960s. Conversion to natural gas happened sometime in the 1970s. The layout, with its mile and a half of 4-inch iron pipe running under the benches of the conservatory and then back to the boilers, remains the same.

Because of the building's age and its limited space, Volunteer Park Conservatory follows a Victorian-inspired model of floral display.

"The focus here is on ornamental horticulture, ornamental display," Helgeson says, "rather than trying to adhere strictly to representations of ecosystems."

A walk through the Seasonal House, for instance, takes you past surging tapestries of shapes, scents and color. Helgeson is curator here, while his fellow senior gardener, Jeanne Schoollmeyer, works in the support greenhouses to raise all the plants he needs to create his public displays.

"You might find plant combinations that don't exist in nature," he admits. "In a building this small, the question is: Which slice of nature do you choose to represent? So rather than limit ourselves that way, we display things as they look best. Our emphasis is on having a visually attractive and appealing experience, to have as much diversity as possible, and to be able to tell the stories of the plants that are of economic importance or of some environmental significance."

The conservatory, he concludes, is a legacy being maintained for future generations.

"It's a wonderful thing to be involved in," he says. "You can't work here and not fall in love with this place. It becomes a part of your life. It's much more than just a job."

Does that mean he takes his passion for gardening home with him at the end of the day?

Not exactly.

"I do it here," he says, "and then my home is a disaster. My wife gardens, but we're both busy and have two teenage children. So not a whole lot of gardening gets done.

"If I can mow the lawn once a week," he laughs, "that's pretty good."

Michael Upchurch: