Make greenhouses from NovaCoru's Homemaker - Expanded Settlements new and clean, with unbroken windows and unbent corrugated metal.  Load it after Homemaker - Expanded Settlements (without the greenhouse disabler) and overwrite anything it asks to overwrite.

My other mods:
Clean Settlement Beds
Clean Shacks
Clean Snap'n Build
Clean Settlement Snap'n Build - Windows Roofs and Doors
Clean Settlement Greenhouses
Clean Settlement Snap'n Build - Greenhouse