Rotary and Drop Walk Behind Fertilizer Spreader Comparison
Professor DeBacco

Walk Behind Spreader Options Questions to Ask…
Questions to ask…
Is the ground established or is it rough?
Rough ground = Rotary spreader
Turf grass established = Drop spreader

What type of fertilizer are you looking to apply?
Pelletized = Rotary
Powdered = Drop

Rotary Spreader
Throws the fertilizer well beyond the width of the spreader.
Can cover large areas quickly.
Best for products that come in a pelletize form

Drop Spreader
As the name implies the product is dropped vertically.
There is an agitator the turns when the wheels move to keep an even distribution of material.
Best in small areas when applying fine or lightweight products.
Overlapping is recommended to ensure even coverage.
Rotary Spreader Swath Measurement
Using a consistent sized and weight pelleted product you can go over some trays and collect the material after a few passes.
This will let you know what the effective swath is for your spreader.

Full Calibrating Rotary Spreaders…
PennState Extension has a full set of instructions…
https://extension.psu.edu/calibrating...
What it comes down to is amount of product applied over an area.

For most home owners you can read the suggestions on your spreader, calculate your observed swath and favor on the low side and make a pass with a known amount of fertilizer.

Check to see how much area was covered per pound and factor this up for your area.

This will help ensure you are not over applying fertilizer for a given area.
Calibrating a Drop Spreader
Since the swath is know (depends on the width of your drop spreader) the same concept for determining fertilizer applied per area as a rotary spreader can be followed.

They key again is to favor on the low side as it is easier to make another pass or increase the drop rate.
Keep in-mind that you should be making two passes to ensure even coverage.

Suggested Starting Point for Reference
Suggested Pattern of Application
Crossing grid pattern to reduce the chance of skipping over an area

If You only get one…
Rotary Spreader is more universal
It can spread powdered forms of fertilizer, but it will be messy and it will clog easily, but it can be done.
This is the design that large operations use… for a reason.
Field Side Comparison
Here is a field side look for two Scott Brand fertilizer spreaders…

Link to Lecture Slides: https://drive.google.com/file/d/1NSPN...

*Due to the description character limit the full work cited for "Rotary and Drop Walk Behind Fertilizer Spreader Comparison" can be viewed at... https://docs.google.com/document/d/1C...