Stepping into the greenhouses at the Lyman Estate in Waltham, Massachusetts, is like stepping back in time. The estate’s story began in 1793, when Theodore Lyman, a wealthy merchant involved in the East India and China trades, began acquiring land for a summer residence and farm. Guided by his English gardener, William Bell, Lyman developed a landscape rich in horticultural experimentation. In 1798, he built the estate’s first nursery: a bark pit greenhouse. Historically known as a “bark stove,” the greenhouse used decomposing bark, a masonry firebox, and solar power to grow exotic fruits and early vegetables. Lyman’s interest in this sort of cultivation was part of a broader trend in horticultural experimentation among Boston’s elite.
Fast forward more than two hundred years: The Bark Pit Greenhouse was no longer functional using its original technology. Over the past few years, Historic New England has undertaken a thoughtful restoration project in partnership with the Massachusetts-based Historic Preservation Corps, a training program supported by AmeriCorps and the Student Conservation Association. This year, Corps members worked with Director of Preservation Trades Omri Nassau to repair historic brick and mortar using eighteenth-century techniques: “hot” lime mortar mixed on site from quicklime, water, and sand. Mortar analysis revealed the presence of natural cement and helped determine the structure’s construction date; matching materials were sourced from the Rosendale quarry in New York.
What began in 2021 as a single training session has grown into an enduring collaboration. Each year, Corps members gain technical skills while contributing to complex restoration projects. At the bark pit, they not only stabilized a rare structure but also deepened their understanding of preservation practice in context.
With work on the bark pit nearing completion, the greenhouse will someday be used again for its original purpose—growing plants. This project is a model of learning-by-doing and the restoration of sustainable, centuries-old horticultural practices. Returning the bark pit to use, both as a greenhouse and a teaching tool, helps ensure its relevance and care for generations to come.
Omri and Anna, a Corps alum, talk about the Bark Pit Greenhouse restoration and what learning preservation techniques in the field means for the future of the historic trades—hear their stories in the video below.
Written by Ciara Foley, Marketing Associate
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