liquid fertilizers #385901

Asked February 20, 2017, 9:07 PM EST

Good afternoon, I came across an article that stated ( A 2-6-0 solution is equivalent to 1 part of 10-34-0 liquid fertilizer diluted with 4 parts of water ) can you please advise how this is calculated ? My reason for asking is I have some 10-8-8 liquid fertilizer that says to add 30 ml per liter of water in doing so does this mean the solution will not be a 10-8-8 and if not what would it be ( how to calculate this )? I appreciate any info you could offer. Kind Regards: John Powell <personal data hidden>

County Outside United States

Expert Response

The 3-digit formulation stated, by law, on prepared fertilizers expresses the relative percentages, by weight of the active chemicals Nitrogen, Phosphorus and Potassium. So yes, 2-6-0 is approximately the same formulation as 10-34-0 (there is approximately 3 times as much Phosphorus, by weight, as there is Nitrogen. The difference between the 2 formulations is approximate 5 times (10% N is 5 times more Nitrogen than 2%). So in theory diluting the stronger formulation would result in a formulation closer to the weaker one; however, the ratio between the chemicals remains the same.

Most liquid fertilizers like this (or called water soluble if in a powder form) are concentrates, so require dilution by water to be safe to use on plants. The dilution rate according to the package instructions should produce a fertilizer close to that listed on the container. A greater or lesser dilution will adjust the formulation totals, but not the ratio between the chemicals (so diluting your example at 15 ml/l water will produce something like 20-16-16. The ratio is the same, only the relative strength differs.

These fertilizers in too-high concentrations can be harmful, so it is recommended to use the dilutions stated on the packages. It is also possible to use a weaker solution (higher dilution) but use more frequently. These chemicals leach quickly, so a weaker but more frequent use can supply a more regular dose for the plant.

Glen Nichols Replied February 24, 2017, 6:24 PM EST

Good morning Mr. Glen N. and thanks for the quick reply to my message, I fully understand your reply,

Sorry but one more quick question, I spoke with Hafia fertilizer company regarding some 21-21-21, first person stated use one kilo per one hundred liter of water ( I did test and this killed the test plants, called them back and they stated try one kilo per 200 liters or 300 and even 400 liters of water.

I understand if example if do 300 liter the ration between the chemicals would stay the same as you advised but how to know the strength of the solution ? just divide by 3 and the 21-21-21 now becomes a 7-7-7 ?? Is my thinking correct or way off ??

Thanks again

Kind Regards: John

The Question Asker Replied February 25, 2017, 11:46 PM EST
Hi John
That would be what I would say, yes; however, it is odd the company seemed uncertain what dilution to be using. It would perhaps be a good idea to confirm the analysis with the company
Glen Nichols Replied February 28, 2017, 8:07 AM EST

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