Calibrating Your Spreader
As summer rolls around, some homeowners will be applying fertilizers and pesticides to their lawns and gardens. It is important to realize that each of these products are labeled to be applied at a certain rate per unit area. To ensure that you are applying the right amount of product, you will need to calibrate your spreader regularly.
One convenient way to calibrate your spreader is the “Sweep and Weigh” method. Push the spreader over a 10-ft-by-10-ft tarp, then collect and weigh the material from the tarp. The weight of collected material is multiplied by 10 to find the rate that would be applied over 1,000 square feet
Alternatively, you could “Weigh Before and After”. For this technique, measure the labeled rate per 1,000 square feet, then spread the material over a 1,000-square-foot course.
Example: A spreader that has an effective swath of 8 feet will need to travel a distance of 125 feet to cover 1,000 square feet (1,000 / 8 = 125). After the course has been traveled, the remaining material is measured and subtracted from the beginning weight to get the rate applied. Since you cannot collect the product dispensed using this technique, do not use this method repeatedly over the same area.
Whichever method you choose, calibrating your spreader will ensure that you are applying products at the appropriate rate for efficacy as well as to protect your plants and the environment.