Understanding Weight vs Ratio N-P-K analysis of nutrients

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Mr.Metal

Mr.Metal

71
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Of coarse we all look at the numbers on our nutes and know we've got a high N, high P-K, or some variation that there of. But what do these ratios really mean? I've always thought a better understanding of the N-P-K's would allow me to not only choose my nutrients more wisely, but be able to customize and provide a more properly balanced diet. I did a quick search of the threads and didnt find anything to extensive on the topic so I did a little more spelunking and here's some stuff I found;
The first is from an old high times magazine article, which may be a bit dated?? I don't know so if anyone sees something completely wrong, or has anything to add PLEASE feel free to chime in!

This write up is from a "03" edition of HIgh Times
Organically speaking

"UNDERSTANDING NPK

Cookin' up chronic requires an understanding of N-P-K. This stands for nitrogen, phosphorus, and potassium

respectively. These are your primary nutrients. All plant-food labels include the percentage of these three

elements in numerical form. N-P-K levels must change to correspond with the different stages of your plant's

growth. There are secondary nutrients and micronutrients also, but these are needed in very small amounts, and

will be present in sufficient quantities as long as you use quality organic fertilizers. You will not need to

know specific amounts , nor will you need to manipulate them.

Within the vegetative cycle, there are separate of growth to recognize. Seedlings with one or two sets of leaves

requires very low primary nutrients to encourage growth. Plants with five-bladed leaves and rooted clones qualify

as early vegetative, and graduate to mild feeding. The next stage is mid-vegetative, and requires aggressive

feeding for robust growth. The week be for initiating flowering is called late vegetative, and is a good time to

throttle back nitrogen by 25% and prepare plants for flowering by feeding 50/'50 mix of bloom and grow

formulas[see below for details]. The flowering cycle also has early, middle and late stages

growth that call for diet adjustments.
Here's my recommendation for N-P-K ratios throughout your garden's life. The length of time between stages

is up to you. You might want to grow six foot trees or a table of one Sea of Greens.


VEGETATIVE:
Seedlings 2-1-2
Early Vegetative 4-2-3
Mid-Vegetative 10-5-7

FLOWERING:
Cycle Changeover 7-7-7
Early Flowering 5-10-7
Mid-Flowering 6-15-10
Late Flowering 4-10-7


Even more important than the actual numbers is the ratio of each of the primary nutrients to each other. The

reason why one farmer can grow using nutrients with a rating of 15-30-15 and another can get identical results

using 5-10-5 is because the proportion of each nutrient is the same. During the vegetative-growth stage,

phosphorus levels should be maintained at 1/2 that of nitrogen and potassium at 1/2-2/3 that of nitrogen. During

flowering, phosphorus takes the lead: Give nitrogen at 1/2 and potassium at 1/2-2/3 the strength of phosphorus.

Notice that potassium is consistently maintained throughout both stages at 1/2-2/3 the level of the main

nutrient. Staying close to this ratio will make sure you don't have a nutrient lock up, when unused nutrients

combine to form compounds that your plant can't use."

Here's another link where they had a pretty clear explanation on the difference between "weight" and "ratio" of nutrients, underlined and quoted below, to provide a little more understanding on what those 3 little numbers are really trying to tell us!!

Found in: "The Fertilization Of Lawns
http://ohioline.osu.edu/hyg-fact/4000/4006.html

"Grass should be fertilized with nitrogen, phosphorus and potassium. Choose a fertilizer with the proper ratio of each of the nutrients to correspond to the soil test results. The fertilizer label must state the percentage by weight of nitrogen, phosphorus and potassium in that order. A 20-10-10 fertilizer has the mineral elements in the ratio of two parts of nitrogen, one part of phosphorus and one part of potassium (2-1-1), as does a 10-5-5. The difference is that weight for weight the 10-5-5 contains half as much fertilizer value as the 20-10-10, and twice as much would have to be used for the same results.”

Hope this helped! And if you've got somethiNg to toss in PLEEEEASE do so!
 
Mr.Metal

Mr.Metal

71
18
From: http://www.sunset.com/garden/garden-basics/crash-course-fertilizers-00400000015144/
Understanding N-P-K

"Regardless of its type, any fertilizer you buy will come with information about the nutrients it contains. Prominently featured will be the N-P-K ratio, the percentage the product contains by volume of nitrogen (chemical symbol N), phosphorus (P), and potassium (K). A 16-16-16 fertilizer, for example, contains 16% nitrogen, 16% phosphorus, and 16% potassium. A 25-4-2 formulation contains 25% nitrogen, 4% phosphorus, and 2% potassium..

And here: http://www.greenviewfertilizer.com/articles/understanding-N-P-K

"To understand how much of each nutrient is being applied to your lawn, you must multiply the weight of the fertilizer bag by the percentage of each nutrient. For example, a 30 lb. bag of fertilizer rated 24-2-8 contains:

N: 24% x 30 lbs = 7.2 lbs. Nitrogen
P: 2% x 30 lbs = 0.6 lbs. Available Phosphate
K: 8% x 30 lbs = 2.4 lbs. Soluble Potash"

I've tried to go through the posted articles (in the links) and highlight what I felt to be the most import pieces of information directly correlated with the topic at hand.
 
ogbluntdoc

ogbluntdoc

125
43
very helpful! thanks for sharing it makes me want to know more. I think i will do some internet spelunking of my own on the subject. I just recently saw a new product at the hydro store called RAW. each package had its individual nutrient so you can completely control your nutrient recipes. I thought only a mad scientist could use a product like that, but now that i have an understanding of these nutrient numbers and how there applied, makes it easier to make my own recipe.
 
caveman4.20

caveman4.20

5,969
313
About three years ago a nutrient company owner tells me that the bottle must read what us instantly readily available to the plant straight out if the bottle for example 0-35-70 means 0% N is instantly available 35% phosphorous instantly available and 70% potash instantly available so to further understand the labeling he used organics specifically and explained how organic nutrients become available to plant after going through organic processes that's why organics have much lower number with just ad much risk if not more to burn or over nute fir example an organic veg base with
2-1-1 after a tea and in the soil for a day and processed by microbeasties may create 10% N in the symbiotic association with root web
 
RonnieB2nd

RonnieB2nd

230
63
Of coarse we all look at the numbers on our nutes and know we've got a high N, high P-K, or some variation that there of. But what do these ratios really mean? I've always thought a better understanding of the N-P-K's would allow me to not only choose my nutrients more wisely, but be able to customize and provide a more properly balanced diet. I did a quick search of the threads and didnt find anything to extensive on the topic so I did a little more spelunking and here's some stuff I found;
The first is from an old high times magazine article, which may be a bit dated?? I don't know so if anyone sees something completely wrong, or has anything to add PLEASE feel free to chime in!

This write up is from a "03" edition of HIgh Times
Organically speaking

"UNDERSTANDING NPK

Cookin' up chronic requires an understanding of N-P-K. This stands for nitrogen, phosphorus, and potassium

respectively. These are your primary nutrients. All plant-food labels include the percentage of these three

elements in numerical form. N-P-K levels must change to correspond with the different stages of your plant's

growth. There are secondary nutrients and micronutrients also, but these are needed in very small amounts, and

will be present in sufficient quantities as long as you use quality organic fertilizers. You will not need to

know specific amounts , nor will you need to manipulate them.

Within the vegetative cycle, there are separate of growth to recognize. Seedlings with one or two sets of leaves

requires very low primary nutrients to encourage growth. Plants with five-bladed leaves and rooted clones qualify

as early vegetative, and graduate to mild feeding. The next stage is mid-vegetative, and requires aggressive

feeding for robust growth. The week be for initiating flowering is called late vegetative, and is a good time to

throttle back nitrogen by 25% and prepare plants for flowering by feeding 50/'50 mix of bloom and grow

formulas[see below for details]. The flowering cycle also has early, middle and late stages

growth that call for diet adjustments.
Here's my recommendation for N-P-K ratios throughout your garden's life. The length of time between stages

is up to you. You might want to grow six foot trees or a table of one Sea of Greens.


VEGETATIVE:
Seedlings 2-1-2
Early Vegetative 4-2-3
Mid-Vegetative 10-5-7

FLOWERING:
Cycle Changeover 7-7-7
Early Flowering 5-10-7
Mid-Flowering 6-15-10
Late Flowering 4-10-7


Even more important than the actual numbers is the ratio of each of the primary nutrients to each other. The

reason why one farmer can grow using nutrients with a rating of 15-30-15 and another can get identical results

using 5-10-5 is because the proportion of each nutrient is the same. During the vegetative-growth stage,

phosphorus levels should be maintained at 1/2 that of nitrogen and potassium at 1/2-2/3 that of nitrogen. During

flowering, phosphorus takes the lead: Give nitrogen at 1/2 and potassium at 1/2-2/3 the strength of phosphorus.

Notice that potassium is consistently maintained throughout both stages at 1/2-2/3 the level of the main

nutrient. Staying close to this ratio will make sure you don't have a nutrient lock up, when unused nutrients

combine to form compounds that your plant can't use."

Here's another link where they had a pretty clear explanation on the difference between "weight" and "ratio" of nutrients, underlined and quoted below, to provide a little more understanding on what those 3 little numbers are really trying to tell us!!

Found in: "The Fertilization Of Lawns
http://ohioline.osu.edu/hyg-fact/4000/4006.html

"Grass should be fertilized with nitrogen, phosphorus and potassium. Choose a fertilizer with the proper ratio of each of the nutrients to correspond to the soil test results. The fertilizer label must state the percentage by weight of nitrogen, phosphorus and potassium in that order. A 20-10-10 fertilizer has the mineral elements in the ratio of two parts of nitrogen, one part of phosphorus and one part of potassium (2-1-1), as does a 10-5-5. The difference is that weight for weight the 10-5-5 contains half as much fertilizer value as the 20-10-10, and twice as much would have to be used for the same results.”

Hope this helped! And if you've got somethiNg to toss in PLEEEEASE do so!
I use RAW NPK entire line. And their npk values are very very high. I think nitrogen alone is 29npk. 7npk I'm the cal mag. But I push my plants. Especially indica. 900 tds in veg an 1700-2000tds in flower and they eat it up.
 

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