How to build a greenhouse
STEP 7. The windows
For the windows use 1 1/2" x 1 1/2" (45 mm x 45 mm) treated or natural decay-resistant wood for the top and bottom horizontal rails and 1 1/2" x 3 1/2" (90 mm x 45 mm) for the side styles and middle mullions.
Angle cut the bottom of the window frame 30 degrees (the same pitch as the roof).
Make two windows as per dimensions above. Fix them in place with two butt hinges on each window screwed to the top rails of the windows and the window support plate.
Fit a window latch to each window.
Measure, cut and fix a row of blocking below the windows and in between the roof frames as shown on the above drawing.