By Clint Waltz
University of Georgia
The two basic types of equipment used to apply granular fertilizers or pesticides to lawns are drop and rotary spreaders. Rotary spreaders are typically preferred to cover larger areas.
Newer models of rotary spreaders have a deflector shield for improved edging around ornamental beds or hard, impervious surfaces. However, you may have to adjust port openings to compensate for a change in distribution. So check the calibration before using deflector shields.
The application rate and distribution pattern are affected by the spreader design, the product (especially weight and density), environmental conditions (wind, temperature, and humidity) and the operator (speed).
Each material will have its own "effective" distribution pattern, so calibrate the spreader for each product being applied. As with all spreaders and sprayers, constant calibration is necessary to assure proper distribution and delivery rate. Consult the owner's manual for proper calibration and maintenance.
Use it correctly
To use your rotary spreaders properly:
- Choose a spreader that's easy to fill and clean, to minimize spills. Make sure the ports (the bottom holes the material falls through) are closed before filling the spreader. And use a cover, especially in uneven terrain.
- Calibrate and know the "effective" swath width for each material being applied. This will determine the proper overlap. When possible, use flags or other markers to track the effective swath width.
- Walk at a constant speed -- 3 miles per hour is typically recommended.
- Keep the impeller (the part that "slings" the material) level and parallel to the ground. Tipping the spreader too far can result in uneven spreading.
- Apply materials while moving forward. Start walking before opening the gate of the spreader, and close the gate before stopping. And avoid sharp turns which make the application uneven. Turn off the spreader before making a turn.
- To avoid skips and streaks, split the rate and apply in two directions perpendicular to each other. Make a lap around the perimeter, and then fill in the interior of the area.
- Avoid applying fertilizer or pesticide to nontarget areas (driveways, roads, bodies of water). Blow or sweep material from hard, impermeable surfaces into the turf area.
- After use, empty the unused material into its original container and wash the spreader thoroughly in an area where the rinse water can't get into the storm sewage.
- Grease and oil all moving spreader parts as recommended by the manufacturer. Check and maintain proper tire pressure.
(Clint Waltz is a Cooperative Extension turf specialist with the University of Georgia College of Agricultural and Environmental Sciences.)