% Slow release N in Dry Fert

Discussion in 'Pesticide & Herbicide Application' started by DA Quality Lawn & YS, Jan 29, 2008.

  1. DA Quality Lawn & YS

    DA Quality Lawn & YS LawnSite Fanatic
    Messages: 9,292

    For northern lawns (kbg, fescue), how much of the total N available in dry granular fertilizers should be slow release. As much as possible? Thanks.
  2. Mscotrid

    Mscotrid LawnSite Bronze Member
    from USA
    Messages: 1,456

    DA, that's a loaded question and I'm sure you will receive various answers. IMO, It depends on the amount of N being appilied and time of year of applications. Normally if I want slow release I go for minimum of 50%. If your throwing a lb of N and only have 20slow, why bother you're still putting down 80% free urea what is the 20% going to compensate.
  3. FdLLawnMan

    FdLLawnMan LawnSite Bronze Member
    Messages: 1,253

    If the lawn is receiving adequate moisture studies have shown that a 50% slow release every 6 weeks gives the most even color and growth. I have one customer that has irrigation so I put down a 75% slow release within two weeks of Memorial day for my customers and then a 50% slow release around Labor Day. If it is less than 50% allow release I don't consider it a slow release, but that is just me. A 50% slow release will last up to 8 weeks depending on the polymer coating used and the amount of rain.
  4. americanlawn

    americanlawn LawnSite Fanatic
    from midwest
    Messages: 5,955

    We've had excellent results with anywhere between 25 - 40 % slow release (granular, balanced, standard prill size fertilizer). App's are as close together as 7 weeks. Up to five app's per year. I spose if one were to make only two app's per year, a higher amount of slow would make sense, but I would charge more.
  5. MStine315

    MStine315 LawnSite Senior Member
    Messages: 789

    It all depends on what you mean by slow release. There are many forms of slow release N, including but not limited to, urea formaldehyde, SCU, PSCU, Methylene urea (MESA), stabilized urea(UMAXX, UFLEXX). I will assume you are asking about polymer coated, as I will go out on a limb and say this is the most widely used in our industry. I think a minimum of 50% of the product should be coated if you want any longevity. The reason I say this, is what the bag says and what's actually still coated by the time it lands on a lawn are sometimes a long ways apart. I would guesstimate 10-15% of a bag could be compromised. So if you start out with only 30%, you'll have a lot less coated product on the lawn than if you start out with 50%. The prills crack, which compromises the release length. If many prills are cracked, you'll have a fast release with very little slow release. How do they crack? Handling the bags is probably the biggest factor. How far are you from the plant? How many bumps did the truck go over? How many times did the bag/ pallet get moved? Did your guys throw them into the truck? Drop them on the ground to break up clumps? Then there's the manufacturing process itself. What's the quality of the coating? I'll stop there, because there are many others who could write circles around me about this, but that's a start.

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