Wild gathering of the leaves of the submerged marine monocotyledon Zostera marina L. once formed the basis of a vigorous insulation industry in North America. Since European colonization, fishing communities used detached leaves, deposited on the beach by tide and wind, as green manure and domestic insulation, but beginning in the late 1800s, these leaves were utilized in a commercial insulating product. Two companies manufactured seagrass “quilts” that were installed in many buildings of the period including some of the first skyscrapers. We here describe the importance of seagrass gathering for the coastal community of Yarmouth County, Nova Scotia, Canada. Interviews with older residents and analysis of county and company archives facilitate the reconstruction of what was once a seasonally important activity. Our findings have direct application to global seagrass protection initiatives.