converting ppm to npk % ?

..macy..

Member
Iv been reading on the net that you can convert ppm to npk ratios but it seems alittle confusing.

e.g. If iv got seperate raw npk's what should my ppm reading be for a 20-0-0 ratio ?

i hope iv made it clear enough :)

thank you
 
e.g. If iv got seperate raw npk's what should my ppm reading be for a 20-0-0 ratio ?
Hey mainliner, depends on how much you would use and in how much water you would put that in.

you can convert ppm to npk ratios
Are you sure it wasn't the other way around, npk to ppm? PPM meters are TDS meters, Total Dissolved Solids. Going back from that "total" to the ratio, requires you to know how much of that total is N, P, and K, which is undoable without measuring the NPK separately using for example a photometer.
 
Hey mainliner, depends on how much you would use and in how much water you would put that in.

Are you sure it wasn't the other way around, npk to ppm? PPM meters are TDS meters, Total Dissolved Solids. Going back from that "total" to the ratio, requires you to know how much of that total is N, P, and K, which is undoable without measuring the NPK separately using for example a photometer.
no i meant ppm to npk , if iv got a bottle of N and i add it to 10 gallons of water , what will my ppm read if lets say i want 13-0-0
 
ppm is mg/L. It's a measurement of mass concentration.


If you want to convert mg/L to percent by mass, you need to know the density of the nutrient solution.

1) Find the mass of 1L of nutrient solution
2) If you have 100ppm of N, that's 100mg of N in a liter

100mg / (mass of 1 liter) = %N by mass.

Keep in mind that the ppm reading on your TDS meter is only an approximation based on EC. If you put 100mg of N in a liter bottle and fill the rest with distilled water, it's actually 100ppm N for real, not an approximation.
 
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