Spreader calibration

Discussion in 'Fertilizer Application' started by JACIRR, Mar 28, 2012.

  1. treemonkey

    treemonkey LawnSite Member
    Messages: 178

    Hi JACIRR,

    I'm a bit late to your calibration question, but let me add what I do. I work at a research institution, so I am a bit more anal about this.

    Spreader calibration has a modest learning curve, but put a bit of time in up front and you will be set to do accurate applications with only modest input to recheck or do new materials. Some spreaders are crazy off on spread pattern and you read about guys here applying in clockwise circles to compensate.

    I do the pan method on a large tarp to adjust the pattern AND to determine EFFECTIVE SWATH WIDTH. The problem with the CUB and Lesco vs. the Anderson is that everytime you change the (3rd) hole to even the pattern, you also change the flow rate (amount). The Anderson's cone system doesn't.

    Ideally, you want even left/right patterns. I have nifty vials to compare the pan collections like this:
    Learn to walk consistent speeds and hold the spreader near level (within reason)....this can change calibration.

    Once I have the swath width and a uniform pattern, I do the calibration amounts like this:

    Prizelawn has a calibration box to collect the material.
    I.E., 10 ft. effective swath.....run the spreader with box 100 ft. = 1000 sq. ft.. Adjust and remeasure until satisfied. Keep a general track of your spread per bag to make sure you are in the ballpark.

    I DIDN'T BUY THE $250 PRIZELAWN BOX. I MADE ONE OUT OF CARDBOARD AND DUCT TAPE (Red Green style). Check out the Prizelawn manual with calibration instructions here: http://www.prizelawnspreaders.com/viewItem.do?itemId=EST-17 In effect, this lets you calibrate a rotary unit like you do a drop spreader.

    Once made, this method is quick, simple, fast, and very accurate (within reason).

    O.K., flame suit on, everyone go ahead and take a stab.
  2. treemonkey

    treemonkey LawnSite Member
    Messages: 178

    Skewed to the right:


    JACIRR LawnSite Member
    from MN
    Messages: 67

    Above is exactly how I wound up calibrating the spreader. It took some time, but found out the pattern was 12' spread.
  4. jvanvliet

    jvanvliet LawnSite Gold Member
    Messages: 3,944

    Nobody checks their speed along with distance? Faster = less & slower = more.
  5. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,808

    You should check your speed on grass as it will tend to be slower than on pavement. Naturally it will be a bit slower on tall grass, uphill, or with a full hopper.
    I travel at about 2.6 miles per hour (that is 229 feet per minute.)
    Of course, my spreader has an electronic speedometer. I can watch it continuously if I want.
    With a half-full hopper on grass, 2.5 mph is more likely, (220 feet per minute).

    Retired now, but I used to spread at 10 feet measured center to center--which is 7 feet between the nearest wheel tracks.
  6. DA Quality Lawn & YS

    DA Quality Lawn & YS LawnSite Fanatic
    Messages: 9,296

    Here is what I do. I have a good idea of the setting range I need for my spreader for the common SGN ferts out there. For my Lesco 80 lb, it is between 11-14. Then I use my OWN lawn to calibrate since I have a measured square footage of my lawn and don't care if I come out a little heavy or light on my own lawn. Then I tweek open or closed based upon my results and bam you are ready to go.

    Not scientific, BUT you don't waste all that fert spreading over pans and making a huge mess and accuracy is still pretty good.
  7. crusty_crab80

    crusty_crab80 LawnSite Senior Member
    from Alaska
    Messages: 426

    So you added a little digital speedometer to your spreader? That is genius. Can you post a pic or tell more about it?
  8. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,808

    OK, Crusty,
    Compliments are always appreciated.
    I finally found the link and photo of the Schwinn bicycle speedometer.


    I bolted a pipe cap to the handle part way down. (Plastic pipe). This serves as a short handlebar on which to mount the speedometer.

    It can also record the sqft covered if you don't mind making a few calculations.

    If you want to record the sqft covered you have to cut the wire and put in a switch so that you are only recording distance when the hopper is open.

    You have to glue a magnet to the wheel, of course.

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