Spreader calibration

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

  1. JACIRR

    JACIRR LawnSite Member
    from MN
    Posts: 67

    I have a few questions about spreader calibration. I have the 80# cub cadet model, and am wanting to calibrate it. I believe it is the same as the lesco models. I have read up on calibrating the spreaders with calibration boxes / pans to figure out the effective spread pattern. Then figure out the spread pattern divided by 1000, to get the length of run to spread 1000 sq. ft. Weigh the material, spread the length and then weigh the material again. This should give you how many lbs per 1000 sq ft correct?

    Also does your effective spray pattern change with the dialing up and down on the settings? Do most people calibrate for every product that they are spreading? Just trying to get some helpful info.
     
  2. Dave Stuart

    Dave Stuart LawnSite Member
    Posts: 98

    Good job so far on the spreaders.

    1000 / swath width = feet needed to travel to cover 1000 sqft.
    Now cone out the distance and see how long it takes to run the length in seconds.

    Catch the rate you want to apply the material at in those seconds.

    Good luck.
     
  3. Dave Stuart

    Dave Stuart LawnSite Member
    Posts: 98

    Also always calibrate all new materials and check the current ones you spread once in a while.

    Have fun.
     
  4. JACIRR

    JACIRR LawnSite Member
    from MN
    Posts: 67

    Posted via Mobile Device
     
  5. JACIRR

    JACIRR LawnSite Member
    from MN
    Posts: 67

    Does you swath width change all the time when you dial up and down on the spreader? I am assuming that it does correct. Thanks so far for all the replies. The more info the better.
    Posted via Mobile Device
     
  6. Dave Stuart

    Dave Stuart LawnSite Member
    Posts: 98

    Only spread volume ( output ) changes when you dial up or down.
    Swath changes with different material densities, the heavier the further the throw, the lighter the closer the swath.
     
  7. Dave Stuart

    Dave Stuart LawnSite Member
    Posts: 98

    Find your effective swath in a bare soil area ( so the prills won't bounce ) / one quick open of the hopper port, then measure the distance.
     
  8. JACIRR

    JACIRR LawnSite Member
    from MN
    Posts: 67

    I already built my calibration boxes to find out if it is spreading evenly. I will adjust the 3rd hole to make sure that that spreads even, then get the effective spread width. The material put down is greater or less with the dialing up and down. I guess if I would have thought about it a bit more, that seems like a common sense thing. This is the 1st time I've had to calibrate a spreader. Usually I get them already calibrated and ready to go with sheets saying how much it is putting down.
     
  9. Dave Stuart

    Dave Stuart LawnSite Member
    Posts: 98

    Your doing fine, the skill that you are acquiring or have acquired is a neglected thing in the industry. 8 out of every 10 applicators can not calibrate properly and don't unstand what they are doing in terms of the calculations.
     
  10. RigglePLC

    RigglePLC LawnSite Fanatic
    Posts: 12,089

    You are being more careful than most of the guys here.
    Let me suggest: Use a bathroom scales and weigh out about 25 pounds. Guess at setting. Apply to exactly 3000 sqft, measured carefully. Pour out and reweigh; find the amount used by subtraction. Calculate the amount used per 1000 sqft. Readjust and repeat. Typical distance between wheel tracks should be 84 inches. Since the spread is wider than this--84 inches allows for feathered overlap.

    You can weigh the spreader and the fertilizer together if you wish.
    Or you can lift the spreader and weigh yourself and the spreader, and still find the amount used by subtraction. Its difficult to see the numbers while holding a spreader full of fert. Let us know how you work it out. Get photos, please.

    For example: you , the spread, and the fert weigh 200 pounds.
    You apply to 3000 sqft.
    Weigh again and get 182. You used 18 pounds.
    Dividing by 3 means you used 6 pounds per thousand.

    If you are apply crabgrass control you do not want to apply too little. So...aim for between 100 and 110 percent of the ideal rate per thousand.

    Count the particles in your boxes to determine the pattern. It should be higher in the first 4 feet and thinner at the edges--to get full coverage you must overlap and feather into the previous swath. Your main concern is to get the left and right sides evenly covered.
     
    Last edited: Mar 29, 2012

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