NPK fertilizer - How to formulate your own

[rodrigo]

I would like to formulate my own fertilizer so I can exactly change the NPK ratios.

I want to formulate for instance:
20-5-10 for growth during rainy season

10-5-20 for spikes during dry cold season

or whatever....

Is there a way to make your own fertilizers with the exact NPK proportions you want?

Has anybody done this?

Thanks,

Rodrigo

[DavidCampen]

I have acquired all the chemicals but since I am still doing finish work on my greenhouse I have not had time to mix my own nutrients and for now I am using Dyna-Grow Orchid Pro.

Perhaps the easiest way to adjust the NPK ratios would be to start with something like Orchid Pro and add say potassium nitrate to increase ratio of potassium to phosphorous or potassium dihydrogen phosphate to increase the ratio of phosphorous to nitrogen. Using something like Orchid Pro would be convenient since it already contains calcium and magnesium as well as all the required trace elements.

Just for fun I will blend my nutrient mix from the basic compounds. Therefore the chemicals I have acquired are:

potassium nitrate
potassium dihydrogen phosphate
calcium ammonium nitrate
magnesium nitrate
ferrous sulfate
zinc sulfate
boric acid
manganese sulfate
sodium molybdate
cobalt nitrate
sulfuric acid

[rodrigo]

Thanks David!

Your list and method are a great start.
Regards,

Rodrigo

[rodrigo]

Hi David,

One more question:
On that ingredient list, what does each of those compounds do in reference to the NPK ratio that you want to achieve?
Thanks,

Rodrigo

[orchids3]

I would be very careful formulating fertilizer from basic ingredients - if you make a miss step you get seperation of the calcium component into a crust which cloggs everything. There is a lot of chemistry involved in making fertilizer. Have been blessed with chemists to consult (son) and an old friend who taught chemistry at MIT (recently deceased at 93).
Jack Peters has a doctorate on staff (daughter) and the MSU fertilizers were formulated by an alumni of Micigan state University with a doctorate - I think we need to consult that type of person. So far I have only found that Muriate of Potash is good to raise raise Potassium - If you try it -try it on a plant you dont like. Continuing to work on this one myself. The only thing I would like to try is off the market in the U.S.

[Intruder]

Look at this link, you will find all you need:
click Here

[rodrigo]

Originally Posted by Intruder

Look at this link...

Wow, the calculator looks awesome!

I wonder if it can formulate "granulated" type of fertilizer that can be applied as dress to the mix also, and not just liquid formulas.

During the rainy season over here, it does not make too much sense fertilizing with liquid.

Anyway, I'm downloading the program while I write this.

Thanks!

Rodrigo

[fishmommy]

I have been mixing my own ferts for about 10 years now with great results. I started doing it for my aquatic plants but carried it over to my orchids without problems about 4-5 years ago.
Many mail-order hydroponics places sell the basic chemical ingredients. It is helpful to start with a premixed fertilizer and then adjust from there.
I use Plantex as a base and then add Boric acid, potassium sulfate, potassium nitrate (if needed), and magnesium sulfate (epsom salts) (if needed). I measure out the ratio I want and mix with water to make a liquid fertilizer concentrate, which I further dilute in water when preparing to apply to my plants.

Plantex is a commercial fertilizer safe for orchids and doesn't mess up the PH of your water or hydroponic solution. I also use DynaGro with great success as a base, but it costs more.

[cday2inflorida]

Originally Posted by fishmommy

I have been mixing my own ferts for about 10 years now with great results. I started doing it for my aquatic plants but carried it over to my orchids without problems about 4-5 years ago.
Many mail-order hydroponics places sell the basic chemical ingredients. It is helpful to start with a premixed fertilizer and then adjust from there.
I use Plantex as a base and then add Boric acid, potassium sulfate, potassium nitrate (if needed), and magnesium sulfate (epsom salts) (if needed). I measure out the ratio I want and mix with water to make a liquid fertilizer concentrate, which I further dilute in water when preparing to apply to my plants.

Plantex is a commercial fertilizer safe for orchids and doesn't mess up the PH of your water or hydroponic solution. I also use DynaGro with great success as a base, but it costs more.

Growing aquatic plants, I learned more about ferts then I ever wanted to know!
I use DynaGro, as well. I'm able to get it pretty cheap at Worms way. I've learned over the years to look for non-urea ferts. I think that is something many people overlook.

[DavidCampen]

So far I have only found that Muriate of Potash is good to raise raise Potassium - If you try it -try it on a plant you dont like. Continuing to work on this one myself.

Muriate of Potash is potassium chloride. I see that it is being sold as a plant supplement but I would not use it on any of my plants. Chloride ion is fairly toxic to many plants. You can buy potassium sulfate for use as a plant nutrition supplement, I would use that rather than the chloride.
Google

Potassium nitrate has an NPK 0f 13-0-45 so pure potassium nitrate has a high potassium ratio. Actually, when you are formulating your own nutrient mixes, getting a high nitrogen ratio is the hardest because that requires ammonium nitrate which is hard to get (assuming that you aren't going to use urea).