Remove the cardboard backing and glass from the picture frame. Place the cardboard backing on top of the screen and mark around it with a marker. This will ensure that the screen will fit the frame. Cut the screen along the marked line. It should measure 11 inches by 8 inches.
Attach the piece of screen to one side of the picture frame by centering it on top of the frame and stapling it on each side. Staple near the corners as well, to keep them from curling up.
Glue a small wooden block to each corner on one side of the frame. This will make legs for the rack so air will circulate around the herbs as they dry. If making more than one rack, these legs will rest on top of another rack. Allow the glue on the herb drying rack to dry completely before placing herbs on it.