The more trials at a given setting, the better will be the average rate of application. Usually three trials at a given setting are sufficient to obtain a reliable application rate. Weigh the material and record the information on each trial run for future use. One of the calibrated settings will approximate the correct rate of material. Since the area for calibration trials is only 100 square feet, apply one-tenth of 10 pounds or one pound of fertilizer per 100 square feet.
Complete calibration is suggested for the complete spreader range.
Settings are not necessarily linear, therefore, half of a particular application range may not necessarily be obtained by using a setting number half the original, thus it is necessary to calibrate the spreader over the entire range of application settings. The same calibration procedure is used for any material you want to apply. Since the quantity applied depends upon the physical properties of the material, the same settings cannot be used for different materials, even if the ratios are the same. Once the spreader is calibrated and set for the proper rate, any size area can be treated accurately. Check the spreader to make certain all parts are operating properly.