Retrofitting older greenhouses can be difficult. Heat
pipes, irrigation lines, plant light, roof support
columns, and other obstructions may have to be
moved before a system can be installed. Blanket
ends and edges must be sealed tightly to reduce air
exchange between the growing area and the attic.
Figure 8–5 shows typical edge sealing methods. A
retracted blanket will partially shade the greenhouse
by as much as 10%. Storing it along the north wall
or under the gutter will minimize shading