Four All Seaons 11-1-1 and 9-1-1 Spreader Calibration Table
First, measure out enough of the fertilizer product to cover 1,000 square feet and put it in your spreader. Next, set your spreader on a low setting. (Usually one-quarter of the way open is a good starting point.) Spread the material you put in the spreader over 1,000 square feet (a 50- by 20-foot area).
Ideally the product will run out right when you get to the end of the 1,000 square foot area. If you have a little left over, just increase the setting a small amount. If you do not have enough to cover the full 1,000 square feet, then you will have to reduce the setting a small amount.
A typical 40 lb bag covers .
Length of Yard X Width of Yard = Square Footage or as an example: 40 X 90 = 3,600 square feet