Metro Parks opens new greenhouse complex on Tacoma landfill

State-of-the-art facility expected to yield long-term water, energy and maintenance savings

Hundreds of velvety poinsettias, graceful amaryllis flowers and scented paper whites swathe the interior of the W.W. Seymour Botanical Conservatory in a swirl of red, green, white and pink.

The showy display, called Lavish, is a holiday tradition at the elegant, Victorian-style greenhouse on the east side of Wright Park.

The Conservatory’s rarefied atmosphere perfectly suits poinsettias, which are tropical in origin. But these plants were nurtured elsewhere. Virtually all of the potted plants displayed as part of the Conservatory’s seasonal calendar of exhibits are grown in greenhouses generally off limits to the public. A set of aging greenhouses on the eastern edge of Point Defiance Park has served this purpose for more than half a century.

That’s beginning to change. The old greenhouses will be dismantled as part of the transformation of the Point Defiance Park waterfront and the $60 million Superfund cleanup of tainted soil left behind by the former ASARCO smelter in Ruston.

Through an agreement with the City of Tacoma, a smaller but more efficient greenhouse complex is in the works on the edge of the city’s old landfill site. Its centerpiece is a 6,000-square-foot, state-of-the-art production greenhouse with automated climate-control system that monitors the weather and adjusts heat, lighting and ventilation accordingly. Estimates suggest the building will save Metro Parks money on water and energy, as well as long-term maintenance.

In October, Metro Parks horticultural technicians and others transferred the first plants from the old greenhouses to the new setting. These included about 1,000 poinsettias, many of which are now on view in the Conservatory, and perhaps an equal number of small ferns of various varieties.

The new steel-framed building has windows of insulated polycarbonate, an extremely resilient type of plastic. It replaces 60-year-old wooden greenhouses that filter light through glass panes. Those were a true maintenance headache, horticultural technician Scott Bassett said. For example, when painting was needed, workers would have to remove and replace each pane.

Adjacent to the new building, Metro Parks crews have relocated steel framing from the old site to erect less sophisticated warm-frame greenhouses and a shaded area. Completion of the entire project is scheduled to take place over the next several months. Money for the facilities comes from the $198 million bond issue approved by Metro Parks voters in 2014.

Moving the greenhouses from Point Defiance has been a topic of discussion for about 20 years. “I never really thought it was going to happen until we broke ground,” said Tyra Shenaurlt, Metro Parks horticulture resource supervisor. She oversees both the Conservatory and the greenhouses.

Among the money-saving features of the new production greenhouse are its parallel water lines, which separate fertilized water from fresh, potable water. At the old greenhouse complex, workers had to purge fertilized water from a single water line before it could be used to irrigate with water alone. According to project administrator Tom Dargan, this upgrade could reduce water consumption 10 percent to 25 percent.

Shenaurlt also expects significant overall energy savings. “We lost so much heat in those other greenhouses,” she said.

When it’s all done, the new greenhouse complex will fulfill all of Metro Parks’ horticultural needs. Besides growing plants for the Conservatory, it will produce the annuals that fill flower beds in Point Defiance Park, along Ruston Way, and in Wapato, Titlow, Norpoint and Dash Point parks.

“This is a really nice, central location,” Bassett said of the new greenhouse campus. The change potentially could reduce the cost of transporting plants to and from display sites. Eventually, a portion of the new campus could be designated as a quarantine area for ailing plants from the Conservatory or elsewhere.

A public open house for the new greenhouse complex is tentatively planned for the spring; a specific date has not yet been set.

                                        – Metro Parks