How much MOP is too much?

Discussion in 'Pesticide & Herbicide Application' started by lilmarvin4064, Aug 11, 2005.

  1. lilmarvin4064

    lilmarvin4064 LawnSite Senior Member
    Messages: 757

    I've seen a bunch of people bashing MOP (Muriate of Potash). Yes, it is a more economical (cheaper) source of potassium, as opposed to SOP, but how much is too much. One lb./1000 sq ft, more, less, and at what temp does it burn? Does anyone have any experiences with burning using a high MOP fert, such as 5-10-31?
  2. jajwrigh

    jajwrigh LawnSite Bronze Member
    Male, from Martinsville, IN
    Messages: 1,405

    You know its too much once the burns begin... :p
  3. go compare the salt index of both of them. sop will also give you sulfer!

    Personal, if growing cool season turf in transition zone, I would avoid muraite of potash
  4. RedEarthLab

    RedEarthLab LawnSite Member
    Messages: 11

    If you need more then 1-2 lb/1000ft2 split the application and monitor the pH and salinity. KCL is best added during the dormant season.
  5. Grassmechanic

    Grassmechanic LawnSite Silver Member
    Messages: 2,697

    I agree Tim. I avoid MOP when ever possible.
  6. Ric

    Ric LawnSite Fanatic
    Messages: 11,969


    Watch for the last Number on the label at the bottom. It stands for Chlorine. Chlorine is used by plants, but in very small amounts. Too much chlorine is a bad thing and is what burns Plants. MOP has a high Chlorine content and will show up on the label as a high percentage.

    A quick rule of thumb went reading Fert Labels is to avoid any Fert that has more than 2 or 3 % chlorine. BTW other compounds of fert have some Chlorine in them also, just not in the high percentage as MOP. All elements in Fert are in fact compounds of several Elements. I know this is rather basic, But time and space are limited so I will stop here.
  7. khutch

    khutch LawnSite Senior Member
    Messages: 497

    These are good threads for a lot to learn from....
    When we talk about "burn", is it unirrigated turf or high temps we are talking about. Is the harm reduced for warm season grasses. I've been using 5-10-31 on Zoysia to get away from high N during the very raining spell we have been having. In hind sight, most of the N would have leached out anyway - who knew 15" in July and another 10" so far in August!
    I realize I've got to bite the bullet and pay for SOP...
  8. the bermunda will better take the higher salt index fertilizer than the cool season turf!

    If you price a bag of sop, then a bag of mop, the sop isn't that much more! If the only ingredient you change is sop over mop, shouldn't be a real noticable price increase, but usually when you buy a complete fertilizer containing sop, the other ingredients are of better quality, thats why the price is considerably more!

    just my experience
  9. Ric

    Ric LawnSite Fanatic
    Messages: 11,969


    How much is TOOOO much??? Wow That depends on so Many Factors that there is no standard answer.


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