Many rate this @ 10:1 NO3:PO4
What many people use may not be what plants use.
Note this site list the levels of N and P and many other nutrients. 10:1 N:P does not equal 10:1 NO3:PO4. You can use a fertilizer calculator to convert NO3 to N. I use this one:
Using the calculator
10ppm of KNO3 dosing results in 2.26ppm N and 6.31ppm K
1ppm of KH2PO4dosing results in 0.33ppm P and O.82ppm K
This results in a total of 2.26 N, 0.33 P, and 1.13K
When scientist measured the amount of each nutrient inside plants they found this
If we use this scientific data to calculate a ratio we get:
Plant nutrient ratios:
If we assume this s the actual nutrient ratio plants need I can calculate the P and K values for 2.26 N which works out to:
2.26ppm N, 1.505ppm K, and 0.301ppm P
For the 10:1 NO3:PO4 ratio we calculated earlier:
2.26ppm N, 1.13ppm K, 0.33ppm P
The two are different. K and P are higher than the science suggest. Is that a significant difference? It looks close but I am not a plant so I don't know. We also don't know how much of a ratio variation there is between the different plants that one can buy. Also the NPK ratio might change from day to day due to differences in leaf, flower, and root growth. There is a lot about plants we simply don't know. So if someone tells you this is the exact ratio you need I would not treat it as fact.
Also don't forget about the other macro nutrients Ca and Mg which are found in plants at higher levels then P. or S and CL levels which are found at levels lower than P. If any one of these are deficient your plants will consum NPK at a significantly slow rate and maybe at a very different ratio than listed. Also any deficiencies in the micros will affect N P or K consumption rates.
If your interested I have also calculated the micro ratios based on the science data I referenced earlier: Micros