Lawn Care/Basics for Homeowners-Lawn Care/Fertilization/Application
 Fate
of Nitrogen |
| Calibrating
a Rotary Fertilizer Spreader |
| Calibrating
a Drop-Type Fertilizer Spreader |
 Results of improper spreading |
Improper spreading results in "streaking", the alternate dark-and light-green stripes in a lawn. Overlap wheel tracks for drop-type spreaders. For rotary spreaders, apply the fertilizer so the wheel is at the edge of the pattern from the previous pass. Use a rotary spreader rather than a drop-type spreader for agricultural type fertilizers (10-10-10, 15-15-15, etc.) that have large particle sizes. Irrigation or rain following fertilization is important to move nitrogen off the leaf blades and into the soil. Some fertilizer/herbicide combination products should not be watered-in, so read the instructions on the label. Avoid fertilizing drought-stressed or dormant turf, or when temperatures are over 80° F. For a much more through discussion of spreaders and application, see: |
Nitrogen leaching into groundwater or
running off into surface water results in water contamination. When applied
correctly, most nitrogen should stay where it is applied. A dense turf canopy
slows water run-off and thus minimizes nitrogen movement across a lawn. The
thatch and dense rooting absorbs nitrogen
and helps prevents it from moving through the root
zone. Be sure to calibrate your
spreader, and follow all label instructions on the fertilizer bag to reduce
the risk of nitrogen reaching waterways.
The distribution is not uniform for a rotary spreader as for a drop spreader. To compensate, the spreader should be run so the edge of the pattern is just touching the wheel tracks form the previous pattern.
For a fuller discussion of ways to protect surface and groundwater quality while fertilizing, see:
(Florida) The Good and Bad in Landscape Fertilization:
http://sarasota.extension.ufl.edu/Hort/Pubs/Fertiliz.htm(Iowa) Iowa State University Cooperative Extension Service
Nonchemical Alternatives for the Home Lawn
http://www.extension.iastate.edu/Publications/PM1680.pdf(Iowa) Nutrient Movement from the Lawn to the Stream
http://www.extension.iastate.edu/polk/water/learning/Article_4_Nutrient_Mgt.pdf(Maryland) Lawns and the Chesapeake Bay (8 pages)
http://www.agnr.umd.edu/MCE/Publications/PDFs/FS702.pdf(Minnesota) Shoreland Landscape Design, Maintenance and Management to Protect Water Quality http://www.sustland.umn.edu/relatedsubjects.html
(Minnesota) Lawn Products on Frozen Ground Can Degrade Water in Lakes, Streams
http://www.extension.umn.edu/extensionnews/2000/LawnCareProductsOnFrozenGround.html(New Jersey) How to Protect Water Quality and Have a Beautiful Lawn: Ten Steps to Proper Fertilization http://www.rce.rutgers.edu/pubs/pdfs/fs829.pdf
(South Dakota) Managing Lawns to Protect Water Quality: Watering, Fertilizing, & Pesticides
http://agbiopubs.sdstate.edu/pub_description.cfm?Item=EXEX1016(Vermont) 12 "Lake-Friendly Gardening" fact sheets
http://www.uvm.edu/extension/publications/lakefriendly/
 |
| Image Source: Texas A&M Turfgrass Program |
| 1. Measure the width of the effective pattern of the spreader: This is simply the distance from the center of the spreader to the edge of one side of the pattern. See "Effective Pattern of a Rotary Spreader" on the previous page. | ________ft. |
| 2. Measure a convenient distance to run the spreader: the longer the distance, the more accurate the calibration. | ________ft. |
| 3. Multiply the step 1 value by step 2 value to calculate the area covered by the spreader. | ________ft2 |
| 4. Weigh a portion of the product and place into spreader. | ________lb. |
| 5. Push the spreader over the area previously measured in step 3, being careful to shut the spreader on and off precisely at the beginning and end of the course. | |
| 6. Weigh the amount of product left in the spreader. | ________lb. |
| 7. Subtract the number in step 6 from the number in step 4. This is the amount of product applied to the area you have measured. | ________lb. |
| 8. Divide the number in step 7 by the number in step 3 to give lb. applied per square foot. | ________lb./ft2 |
| 9. Multiply the number in step 8 by 1000 to give lb. product/1000 ft2 | ________lb./1000 ft2 |
| 10. Adjust the spreader setting and repeat the calibration if necessary until the spreader is applying the recommended rate listed on the bag. |
 |
| Image Source: Texas A&M Turfgrass Program |
| 1. Measure the distance between the outside holes of the spreader. | ________in. |
| 2. Convert this to feet by dividing by 12. | ________ft. |
| 3. Measure off a convenient distance to run the spreader: the longer the distance, the more accurate the calibration. | ________ft. |
| 4. Multiply the step 2 value by the step 3 value to calculate the area covered by the spreader. | ________ft2 |
| 5. Weigh a portion of the product and dump into spreader. | ________lb. |
| 6. Run the spreader over the area previously measured in step 3, being careful to shut the spreader on and off precisely at the beginning and end of the course. | |
| 7. Weigh the amount of product left in the spreader. | ________lb. |
| 8. Subtract the number in step 7 from the number in step 5. This is the amount of product applied to the area you have measured. | ________lb. |
| 9. Divide the number in step 8 by the number in step 4 to give lb. product per square foot. | ________lb./ft2 |
| 10. Multiply the number in step 9 by 1000 to give lb. product per 1000 ft2 | ________lb./1000 |
| 11. Adjust the spreader setting and repeat the calibration if necessary until the spreader is applying the recommended rate listed on the bag. |
Click here for for a 5-graphic sequence showing how to do this:
Click here for a 5-graphic sequence showing an alternate way ("catch pan") of doing this: