Suzana, one of the first members of My Grape Vine, send me this question a few days ago.

She wanted to know what those numbers on a fertilizer packaging means.

With this article, I will show exactly what they mean and how you can calculate, precisely how much of a certain fertilizer mixture you must apply, in order to get the right amount of an element in your soil.

The numbers on a fertilizer mix like for example a 10:10:10 fertilizer, probably the most common of all, means:

10 : 10: 10

N  :  P :  K

10 parts nitrogen (N), 10 parts phosphorus (P), 10 parts potassium (K)

 

But that’s not all!  On many fertilizer packages you see a 4th number in brackets; for example

2:3:4 (27)

 

From what we have just learned, we will have

 

2 parts nitrogen (N),  3 parts phosphorus (P),4 parts potassium (K)

 

The fourth number (27) – in brackets – is the total percentage (%) of nutrients in the mixture.  

So we have a total of 9 parts ( 2 + 3 + 4) nutrients in that mixture, that ads up to 27% of the total mixture.

 

In other words; for every 100 kg of fertiliser there will be a total 27 kg N, P, K in the mixture.

                                            2          27

the nitrogen (N) is                  9   x     1      =   6     kg N for every 100 kg of fertilizer mixture

 

Therefore, two ninths of 27 kg, or 6 kg, of every 100 kg of mixture will be nitrogen.

 

As for a 1:0:0(40) mixture, 40 kg Nitrogen will be added to the soil for 100kg fertilizer and no P, K

 

I hope this makes sense? :-)

With this formula, you can easily calculate how much of a certain fertilizer mix you must apply to add a certain amount of N:P:K to the soil.

To Learn Even More About Growing Grapes,

Join The Complete Grape Growing System Today!

For a once-off fee of only $29, you get instant access to all the grape growing info I use on my own farm, plus some bonus pruning and training videos!

The Complete Grape Growing System is an online product.  You will NOT receive any physical products with your order

Share and Enjoy

Tagged with:

Filed under: growing grapeshow to grow grapes

Like this post? Subscribe to my RSS feed and get loads more!