Read the bag of powdered lime, and determine how much lime you need to spread on your lawn. Usually the bag will tell you how many pounds per acre or 1,000 square feet. Soil tests will also suggest how much lime needs to be applied. If you need help with this, take all the measurements to your local department of agriculture.
Place your mask over your nose and mouth, and put on goggles when you pour the lime into the lawn spreader. Then fill the lawn spreader only halfway with lime to eliminate the lime from bunching together; you want the lime to sift down through the lawn spreader.
Spread the lime, using the lawn spreader evenly over your lawn. Keep track of how much you are using as you spread it. Reapply if needed on the same day.
Water or till the lawn if you can to help the lime sink into the soil. Lime takes awhile to sink into the soil and a strong rain could wash it away. Mixing it with a rototiller or softly soaking it in with a hose will help.