Hitch height is an important detail on drawn spreaders as it affects the pitch of the spinners at the rear of the machine. Consult the operator’s manual for the machine being used.

Wind speed should be less than 5 mph when making applications. Strong winds and especially gusting winds can significantly alter the spread pattern.

Quality of material

The quality of material being spread can affect spread pattern, particularly material that contains a significant amount of very fine particles (dust) or large clumps.

Large clumps can partially block off the opening under the gate, reducing the rate of application by reducing flow. To avoid large clumps from forming, keep fertilizer as dry as possible.

Material that contains a significant amount of dust and small particles will be more difficult to spread evenly with spinner-type spreaders (it’s hard to throw dust). To avoid making fertilizer dust, reduce handling as much as practical, especially with augers.

Spreader adjustment

Always consult the operator’s manual before making adjustments to a spreader. Begin by examining the spreader for mechanical issues such as heavily corroded or missing parts. Second, check for bent components such as the flow divider on double spinner models or a bent spinner support frame.

To check the spread pattern, obtain a pattern test kit. A pattern test kit will contain catch pans with dividers that fit in the bottoms of the pan.

These dividers are in place to keep particles from bouncing out of the pan. Set up a test course on a level field with one pan in the center of the course that will be straddled by the spreader; the rest of the pans should be evenly spaced in a line perpendicular to the direction the spreader will travel.

Use at least 10 pans for the effective spread width with additional pans placed beyond the effective spread width so any material thrown beyond the intended spread width will be collected.

Many test kits use a series of tubes where material collected in the pans is placed for easy visual comparison — be aware that visual inspection can be misleading if fertilizer particles are not of uniform size.

Weight of material collected from the pans will typically be a more accurate measurement.