callabrate your spreader?

Discussion in 'Pesticide & Herbicide Application' started by fga, Sep 29, 2004.

  1. fga

    fga LawnSite Silver Member
    Messages: 2,449

    does anyone really do this? for grass seed, fertilizer, etc. or do you trust the settings an "eye it"?
  2. tiedeman

    tiedeman LawnSite Fanatic
    from earth
    Messages: 8,745

    I usually have it figured out after the first or second application. I never go by the settings because they are always wrong
  3. MrBarefoot

    MrBarefoot LawnSite Senior Member
    Messages: 515

    The calibration settings are good places to start, but you should adjust as you go. Watch your usage after a few lawns and then bump it up or down as necessary.
  4. GroundKprs

    GroundKprs LawnSite Bronze Member
    Messages: 1,969

    Myself and another guy here do calibrate every winter. Use a friend's auto shop on weekends. For those who don't know about it, here's real spreader calibration
  5. heritage

    heritage LawnSite Bronze Member
    Messages: 1,358

    GroundKprs suggestion is very good. I would like to suggest an easy way to calibrate a granular rotary or pendilum spreader.

    Materials particle sizing varies, sometimes with high quality product also. So You should re-calibrate whenever you are applying product from a new batch.

    The letters/numbers on the bag are just a starting point for the calibration process. With new product in hopper you should first adjust your spread pattern so it appears to be applying uniform from left to right using the #s on the bag.

    Next make 2-3 passes on a test area of turf 10-15 feet in length and spread back to the closest wheel mark from your last pass.

    Now measure the distance from the center of your wheel marks to the center of your next pass wheel marks.

    Divide 1000 by the number in feet between wheel marks and record this number.

    Next weigh out the amount of product you need to apply for 1000Sq.Ft. and add this amount to an empty hopper.

    The number you came up with by dividing 1000 sq ft by the effective spread width is the distance you should cover in one continuous pass. Adjust up or down until you are close and you will be ready to make applications within 5% accuracy.

    Pete D.
  6. kickin sum grass

    kickin sum grass LawnSite Senior Member
    Messages: 628

    I agree with everyone that from time to time you need to go thru and do the above calibrations but you should be calibrating as you work thru the day everyday. What I mean is that you should know how much product is needed on a lawn and then see how much you use. As you get tired at the end of the day and slow down you will need to bump the spreader down. Also you need to watch the pattern of throw on a regular basis. Don't just go thru and do an initial calibration and think it will always be fine. Watch it from day to day and job to job.
  7. GroundKprs

    GroundKprs LawnSite Bronze Member
    Messages: 1,969

    Great observation, kickin. Calibration of every job is a must if you want to provide consistent results. Covers the variance of particle size in different batches mentioned above.

    More importantly for me, it measures the change in humidity over the day. As humidity increases, fertilizer particles will become a little more sticky, and flow rate will be reduced. I have seen days where using the same setting all day would get you only 2/3 to 3/4 the rate at 3:00 pm that you were getting at 8:00 am.

Share This Page