When it's finished, the greenhouse at Harkness Memorial State Park will be a near exact replica of the original built in 1910 - at least by outward appearances.

The $950,000 restoration project, which began last month, is being undertaken by Kronenberger & Sons Restoration of Middletown, with the costs split between the state and the Friends of Harkness. The 800-member volunteer group raised most of the funds at its annual plant sales, while the state's funds came from rental fees for weddings and receptions held at the mansion on the property, Eolia.

Jay Veillette, project manager for Kronenberger, said this isn't the first historic greenhouse restored by his company, which also restored Eolia. Still, the project is unique, he said.

The work began with removal of lead paint and asbestos on the steel frame. After that the frame was removed and will be replaced with aluminum - a change from the original that will not be subject to rusting. Dozens of sheets of tempered glass for the exterior of the greenhouse will be delivered to the site by Under Glass Manufacturing Corp., a High Falls, N.Y.-based company that purchased the assets of the original company that manufactured the greenhouse, Lord & Burnham, Veillette said. The doorways will be rebuilt with exterior moldings and other details matching the original.

"We'll refurbish all the potting tables, and all the piping will stay in place, and update some of the heating," he said.

Modern equipment such as computerized controls for the heating system and underground utilities will be installed, but hardware such as the manually operated cranks to open vents on the greenhouse roof will match the original. An old cistern that supplied water to the greenhouse will also be restored and put back in service.

"It'll be about six to eight weeks before you'll start to see a structure," he said. By November, a rebuilt central greenhouse of about 15,000 square feet is expected to be completed. Replacement of the east and west wings - where Italian grape vines planted for the original owners survive - will await a later phase, after more fundraising.

Park Supervisor Mark Darin said that once the greenhouse is complete, it will be used to start plants for the flower gardens around the mansion, a major attraction of the park. Currently, the state pays about $15,000 per year for annuals for the gardens, which the Friends group helps maintain. The greenhouse will also be used for educational programs about garden history, landscape design and horticulture.

Even with its rusted frames bare of glass, Darin said, the greenhouse attracts a lot of interest from visitors.

"You'd be amazed how many people come over here for photographs," he said. "This is going to be fabulous when it's done."

The original owners of the estate, Edward and Mary Harkness, used the greenhouse to grow all the flowers, fruits and vegetable plants for their gardens. All the fruits and vegetables served in the mansion were grown on the property, with extras sent to the wealthy couple's other homes or given to charity. The Harknesses also kept dairy cows.

Christopher Callahan, president of the Friends of Harkness, and Eileen Grant, a trustee of the group and head of Friends of Connecticut State Parks, said seeing the greenhouse project finally get under way is very gratifying. The group has been working for 17 or 18 years to raise its share of the money. The greenhouse was an important structure on the Harkness estate, they said, and seeing it restored means one of the main goals of the Friends group is being reached.

Because of the new life and growth that takes place inside them, Grant added, many people are naturally drawn to greenhouses.

"It's like a living thing," she said.

J.BENSON@THEDAY.COM