What percent overlap should you use on passes when using a rotary spreader for a uniform granule application?

• A. 30%
• B. 10%
• C. 60%
• D. 0%

Answer: (A)

Uniform coverage with a rotary spreader comes from how much your passes overlap. The spreader throws granules outward in a spread pattern, and to avoid visible stripes or gaps you want each new pass to overlap a portion of the previous pass. If you don’t overlap at all, you’ll see clear bands where the product didn’t reach. A very small overlap, like 10%, still leaves noticeable stripes because the edges don’t get enough material. Overdoing it, such as a 60% overlap, causes a lot of double application in the overlap zones, wasting product and potentially causing over-application in those areas. About 30% overlap strikes a practical balance: it smooths coverage across the area without creating excessive buildup where passes overlap, giving a uniform application overall.