Spraying SOP? (Riggle, Green Doctor, any others)

Discussion in 'Fertilizer Application' started by Toro 44, Mar 4, 2014.

  1. Toro 44

    Toro 44 LawnSite Member
    Posts: 155

    I normally apply K in granular form as SOP. But I'm looking for a good sprayable K source.

    There are 3 criterion I'm using:

    1) Solubility

    2) Salt index

    3) Price

    I thought that SOP was my answer. Other than potassium Carbonate, it has the lowest salt index and is affordable. But I have concerns about solubility. I may be spraying 1/2 pound of N in the form of stabilized urea. I'd like to add 1/4-1/2 pound of K with it.

    My typical spray volume is between 1.5 and 2 gallons per 1,000 square feet.

    I like potassium carbonate, but it seems very hard to get and pricey.

    I've heard Green Doctor talk about potassium nitrate, but it is a little more expensive, has a higher salt index, and according to "Turfgrass Science and Culture" can deflocculate the soil when used over time. BTW my soils have a good deal of clay and tend to be acidic.

    Does anyone have experience dissolving and spraying SOP (Riggle)? How much do you apply and what spray volumes were you using (2.6 g/m)? Seems like for a given amount of SOP, I will need at least 10 times that weight of water to disolve it. According to the solubility chart on wikipedia, Potassium Nitrate has about twice the solubility as SOP at the temps I'd be mixing in.

    Thanks in advance!

    P.S. It's not uncommon for my soil tests to come back needing sulfer. The sulfate in SOP is helpful this way
     
  2. ArTurf

    ArTurf LawnSite Gold Member
    Male, from Ark
    Posts: 3,325

    I think I've read where Ric has used disolved SOP but he applies at 5 gallons per 1000.
    Why are you starting to apply in liquid form vs granular, just wondering?
     
  3. Toro 44

    Toro 44 LawnSite Member
    Posts: 155

    I'm doing it because most of my properties are small and a ride on is not practical. So instead of walking all my properties twice to spray and spread, tank mixing makes a lot of sense.

    Plus luquid apps give me more flexibility in what i apply.

    Thanks for your reply by the way.
    Posted via Mobile Device
     
  4. ReddensLawnCare

    ReddensLawnCare LawnSite Bronze Member
    Posts: 1,652

    Can someone please define SOP for me. Please excuse my ignorance on the matter
    Posted via Mobile Device
     
  5. Toro 44

    Toro 44 LawnSite Member
    Posts: 155

    Sulfate of Potassium aka Potassium Sulfate.

    Hey AR,

    I saw in a 2011 thread on liquid fert that you told green doctor that you found an affordable source for soluble SOP. Did you ever try spraying it?
     
  6. Toro 44

    Toro 44 LawnSite Member
    Posts: 155

    double post. sorry
     
  7. ReddensLawnCare

    ReddensLawnCare LawnSite Bronze Member
    Posts: 1,652

    Thank you
    Posted via Mobile Device
     
  8. greendoctor

    greendoctor LawnSite Fanatic
    Posts: 8,821

    In acidic clay, you want calcium nitrate as your N source and potassium nitrate for the K. No, it will not defloculate the soil provided you pay attention to the calcium levels. Because I often need to use calcium nitrate to correct magnesium excesses, sodium excesses, and acidic soil, potassium sulfate is no good for me. It forms concrete if mixed with calcium nitrate. I can also tell you that a good rule is no more than 1 lb of N per 10 gallons of solution. Especially in dry, non irrigated lawns. That rule is broken with me because I am spraying on lawns that were watered that morning and I am going to short cycle the system after application.
     
  9. ArTurf

    ArTurf LawnSite Gold Member
    Male, from Ark
    Posts: 3,325

    No I didn't, I'm not really set up well for liquid fert.

    I have my dry ferts custom blended to use SOP, maybe that's what I was speaking of.
     
  10. jalderfer63

    jalderfer63 LawnSite Member
    Posts: 99

    Have you tried Synatek out of Souderton.They have some good liquid fert options.
     

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