help needed to calculate ppm

[sharath]

hi everybody, i use a fertilizer mix that reads 5 15 30 and its a 10gms pouch they say u have to dissolve it in 5 liters of water. i am bit confused about calculating ppm of NPK. i used the ppm calculator. N 109 P 144 K 542 and i really dont now its right or not can somebody help me thank u

[Halloamey]

Hi Sharath, PPM is equivalent to mg per litre, here goes the calculation.

NPK 5:15:30 means that your fertilizer is 5 % N, 15 % P and 30 % K and the remaining 50 % is binding material which ideally should be inert.

1 gram (g) is 1000 milligram (mg)

therefore 1 g fertilizer contains 50 mg N, 150 mg P and 300 mg K.

Now, PPM stands for parts per million,
i.e a solution with a concentration of 1 ppm has 1 part of the solute in a million parts of solvent.
therefore a 1ppm fertilizer solution is a solution of 1mg fertilizer in 1 million mg of water,
1 million mg of water is 1000 g which is 1 litre.

So if you dissolve 1 g of your fertilizer in 1 litre of water you will have 50 ppm N, 150 ppm P and 300 ppm K.

I usually fertilize my plants with a balanced fertilizer which is 200 ppm of each NPK ( 1g 20:20:20 in 1 litre water.)

[Alana]

Great explanation!