I'm neither
padredurand nor
blackbird (
nor is this any stupidity on your part, by any stretch), but (Why did I get kicked "off log" in under 10 minutes on the BB, and have to "log on" again so soon?? This is ridiculous!!!!)
Now where was I??
Oh yeah!
13-13-13 is the signature for the three most common, necessary elements to plant growth (and often elements that are either lacking or unavailable in an easily available form to the plants from the soil), in plant food, N, P, & K or Nitrogen, Phosphorus, and Potassium.
They stand for the percentages of actual elemental nitrogen (expressed as N
2), what called "phosphate" (actually P
2O
5) and "potash" (K
2O).
Therefore 2 of the 50# bags (equaling 100#) of 'Triple 13' fertilizer would contain materials (usually granulated) that would give one
13# of N
2,
13# of P
2O
5, and
13# of K
2O.
In actual practice (here in Central KY at my friendly local fertilizer plant), the materials this would contain would likely consist of ammonium nitrate ('analysis' of 34-0-0), a material known as "DAP" (short for Di-Ammonium Phosphate - 'analysis' of 18-46-0) and one known as 'Muriate' of Potash (or M/P - 'analysis' of 0-0-60), and enough "filler" materials (usually coarsely ground agricultural limestone, at least in my area) to make up the weight. [If the fertilizer was labeled 13-13-13S, the S suffix means that the 'potash' source is "sulfate of potash" which is sometimes used for various crops (notably tobacco, in my area), in place of the 'muriate' of potash.]
That would commonly translate into roughly 23# of Ammonium Nitrate, 30# of 'DAP', and 22# of 'muriate' of potash, plus 25# of limestone 'filler',
+ a # or so, for each of the materials, per 100# of fertilizer. One can vary these quantities, with some different materials, and still arrive at a 13-13-13, BTW.
Or one can have this analysis (or about any other possible 'analysis') "custom blended" in the "tons" quantities I commonly use on the farm, at my friendly, local fertilizer plant. I would likely add some other materials to the mix (and eliminate the 'filler' entirely), depending on the crop to which I was applying the fertilizer, but you can get the basic gist of the process, from the above.
[SIGH!] 'Kicked off log', again! Meaning I have had to 'log-in' 2 times (plus copy and paste my response) just to post this reply!
Ed