# SOP will not dissolve in water??



## spud (Apr 14, 2019)

Everything I've read says SOP is easily dissolved in water, but I bought this last fall and applied 1/2 of the bag. Even after the whole winter there were small very hard "rocks" left in the spring (not good for the reel mower). This fall I've been trying to dissolve the rest in a 5 gallon bucket of water to apply as a liquid. It's been 2 months with stirring every week or so and still not dissolved!

Any thoughts?


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## g-man (Jun 15, 2017)

spud said:


> Everything I've read says SOP is easily dissolved in water,


SOP does not dissolve in water that easy. You will need to buy a sprayable version. Just apply it in granular.


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## CarolinaCuttin (Sep 6, 2019)

@spud

What @g-man said.

It will take quite a while. Mowing through fertilizer granules is unlikely to hurt your reel mower, but if you actually have rocks like you are saying then it is likely impurities in the mix and not actual SOP.

The solubility of SOP is quite low especially compared to other common fertilizers like urea or ammonium sulfate. You can easily get 350g (0.77 pounds) of SOP to dissolve to make a gallon of solution. For comparison, you can get almost 4 pounds of urea in the same gallon of solution. Odds are you probably haven't added enough water OR there are significant impurities that are settling to the bottom. These can easily be removed by pouring the mix through a strainer lined by a paper towel.


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