Spreader Calibration Helper
Check what your spreader puts out per square metre at a given setting, and whether to open it up or close it down to match the label rate.
- Lay a tarp over a measured area, or use a clean driveway.
- Fill the spreader with the product you'll apply and set it to the bag's suggested setting.
- Walk over the area at your normal pace, then sweep up and weigh what landed.
Your spreader's output
Enter your test area and how much you collected.
How it works
Uneven granular applications cause stripes of dark green and pale grass, and too much in one spot can burn the lawn. Calibrating your spreader against the label rate takes ten minutes and fixes both problems.
Worked example
Spread over a measured 10 m² on a tarp or clean driveway at your normal pace, then sweep up and weigh what landed: 150 g. That's 15 g per m². If the label rate is 25 g per m², open the spreader up a setting and test again.
What you enter
- Test area in m²
- Amount collected in grams
- Optional label rate in g per m²
What you get
- Output in g per m²
- Whether to open up or close down the spreader
Assumptions
- Use the product you will apply; different granules flow differently. Walk at the speed you will use on the lawn.
Questions
Why not just use the setting on the bag?
Bag settings are a starting point for specific spreader models. Your spreader, its condition and your walking speed all change the output, so a quick check is worth it.
Do I need to calibrate for every product?
Yes, ideally. Granule size and weight change how a product flows through the spreader.