Mixing your own Fertilizer

i have on hand 50# of 15-0-15 and 5# of 0-46-0.
>
> how much of 0-46-0 do i need to add to make a 15-15-15 fertilizer
>
> or close to it
>
> thanks wayne
>
>
> Wayne& Group:
>
> What you would REALLY like to have is 13-7.5-13! That is the ratio
in the Pre-mixed Mittleider Magic fertilizers that are sold in the
Mountain West, and that's what I'd tell people how to make, if the
stores sold the right materials to make it.
>
> You have a GOOD situation for making a Weekly Feed mix that is very
good.
>
> Mix 28# of your 15-0-15 with 5$ of the 0-46-0, and you'll have 4.2N
- 2.3P - 4.2K.
>
> If you're mixing with the pre-mixed micro-nutrients from the
Foundation, just use 20# of that NPK mix, along with 3# of magnesium
sulfate, and you've got a good Weekly Feed.
>
> Jim Kennard
>
Jim, to help me (and all of us) understand this mixing, is the basic
formula for mixing your NPK to ensure that each of the N, P and K are
in 13-7.5-13 proportion. For each part of P, you need 1.75 parts of N
and K?

So, in the example above, 5# of 0-46-0 would have 46 x 5 parts of P =
230. This needs 1.75 times 230 = 402 parts of N and K. Since each #
of 15-0-15 has 15 parts of N and K, divide 402 by 15 to get 26.8#.

Or is my formula off?


group:

It's really quite simple. The ideal NPK ratio is 110-60-110. That is a RATIO - not percentages. This is "the preferred horticultural mix", according to some of the big fertilizer companies.

Then why don't they sell it that way? That would mean one fertilizer would feed all plants, and they wouldn't make much money. Of course they would also need to add the secondary and micro-nutrients, but it would be a start anyway.

Jim Kennard