Now quit iCal.
In Safari choose Page Setup... under the File menu
Select your Printer under "Format for:"
Under "Paper Size:" select "Custom Size" at the bottom of the list.
Click on the Plus symbol ➕ to create a custom size.
It should default to 8.5 x 11
Give this a name by double clicking on "Untitled" (eg Calendar Margin)
Set the left margin to 1 or 1.25 (or whatever you want).
Click OK
Open iCal
Select Print
Under "Paper;" select your new paper.
Carry on