could be the dumbest question on rates but here goes

Discussion in 'Pesticide & Herbicide Application' started by grassmasterswilson, Mar 31, 2010.

  1. grassmasterswilson

    grassmasterswilson LawnSite Platinum Member
    from nc
    Messages: 4,872

    I have been doing this for a few years now and my business is really growing. I have had great sucess following the labels, but as I am getting bigger I am also trying to cut cost. So here is an example of my question....

    Let's say you are targeting broadleaf weeds using speedzone southern or any 3-way/chemical. The rate for warm season grasses is 0.75-1.5oz/1000 and cool season is 1.5-2.2 oz/1000.

    So my question is if .75 oz will kill broadleafs in warm season why wouldn't it work on cool season? Can I assume that the rate is geared more towards the tolerance of the turf to the chemicals? There would be a big difference in cost of .75 oz vs 2.2 oz.
  2. jbturf

    jbturf LawnSite Bronze Member
    Messages: 1,483

    good question- that is a pretty extreme difference.
    i think your assumption of turf tolerance is accurate.

    in the end, it will be your own experience and knowledge that
    will allow you to use the lowest effective rate. and knowing your target
    weed is probably the biggest factor here. for example-i know from experience with
    the mentioned product that the .75 rate will destroy a dandi but not
    effect a mature wild violet plant or mature plantain.
  3. Weeded!

    Weeded! LawnSite Member
    Messages: 19

    I believe there are two possible reasons for the variation in application rates:

    1. Less tolerance among warm season grasses
    2. It is more likely to be WARMER where there are Warm season grasses, thus less chemical is required to A. Kill the weed and B. Harm the turf.

    Depending on the round, I sometimes mix the herbicide at a lower rate for blanket sprays and then do a double or triple pass on weeds depending on the type of weed. Consider what else you are spraying if you use this method as you may get a greener/taller spot if there is fertilizer in the mix.

    If we are doing a spot spray only round I will mix at full rate, or, usually, do a backpack application. Cost may be just a couple of dollars to spot spray an entire yard.

    Careful when doing a spot spray with a larger tank of the initial blast due to pressure build up in the line. That might be a double pass right there. Perhaps scale back the pressure.
  4. LawnoftheMonth

    LawnoftheMonth LawnSite Senior Member
    Messages: 356

    I use the highest rate when it's below 70 degrees here and the lowest rate when it's above 72 or so. The hotter it is the better my weed control works, I dont cut back to save money, it's just to reduce any risk of turf damage.

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