# rock phosphate



## r7k (Jan 25, 2019)

> Soil test values for PHOSPHORUS are BELOW OPTIMUM...
> 
> In addition, apply 9 lbs of 0-46-0 (triplesuperphosphate) or 20 lbs of 0-20-0 (superphosphate) or *134 lbs of 0-3-0 (rock phosphate)* per 1000 sq ft in either spring or fall.


how does one buy "rock phosphate" in necessary quantities?

I have 6,000 square feet: 134 x 6, how do I get 800 lbs of 0-3-0 rock phosphate?


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## g-man (Jun 15, 2017)

I think you should look for triple super phosphate (0-46-0). You can also use MAP (11-52-0) or DAP (18-46-0). The last two have a small amount of N that you need to account for.


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## adgattoni (Oct 3, 2017)

They are basically wanting you to add 4lb of phosphorus. I found TSP to be pretty expensive per pound of P. You could just switch to a balanced fertilizer next year and put out 1# P/M/month. I just used starter fertilizer.


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## r7k (Jan 25, 2019)

my analysis also said i needed potassium and to use X lbs of 0-0-60.
I mentioned that to the store where i just bought lebanon pro fertilizer, they never heard of 0-0-60.
They also mentioned _the ban_ on phosphorus while asking them about phosphorus and showing my soil test, and all they knew about was "starter fertilizer".

when P comes back low is the university soil lab just cutting/pasting text from < 1980 ?
why even mention _rock phosphate_ or any other high P one if it's not available?

I see mail order for triple super 0-46-0 but at like $15 for 5 lb bags.
I need about 80 lbs, i see EasyPeasy on amazon 20 lbs @ $50 = $200. Is that reasonable?
Everything seems to be in handheld size bags for like indoor gardening pots, is there anything available for lawn size quantity?

I'm figuring on just doing starter fertilizer applications in place of typical 25-0-10 stuff.


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## desirous (Dec 15, 2017)

To answer your original question, you can buy soft rock phosphate 0-3-0 here: https://www.7springsfarm.com/calphos-granular-0-3-0-50-lb-being-replaced-with-fertoz-0-7-0-link-below/

In the quantity you are looking for, shipping is "reasonable", it about doubles the cost of a bag. Been there, done that. In theory, soft rock phosphate is a lot gentler and longer lasting than the "super" alternatives. It's also slower and more expensive. You are probably better off with the more cost effective, chemically enhanced options that @g-man mentioned above.


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## adgattoni (Oct 3, 2017)

r7k said:


> my analysis also said i needed potassium and to use X lbs of 0-0-60.
> I mentioned that to the store where i just bought lebanon pro fertilizer, they never heard of 0-0-60.
> They also mentioned _the ban_ on phosphorus while asking them about phosphorus and showing my soil test, and all they knew about was "starter fertilizer".
> 
> ...


0-0-60 is muriate of potash (MOP), 0-0-50 is sulfate of potash (SOP). Most do not use MOP because of the chloride content. SOP also has sulfur which has it's own benefits in addition to the potassium.

I would bet rock phosphate is moreso used in large agricultural settings where they plow it into the soil, which BTW are the larger users of soil testing labs - they aren't making bank on homeowner soil samples.


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