hello,
when I'm browsing around at some garden stores and look at their organic (as well as non-organic) fertz, I see some npk values such as 10-12-8, some 21-15-10, and some .5-.4-.2 etc...
does this mean the 21-15-10 is, say, stronger than the 10-12-8??
and what about the .5-.4.-2?? is this suppose to be a very weak fertilizer? I'd prefer something a bit more powerful.
Looks like the numbers are a percentage of the respective nutrient. Here's the first hit google came up with for "npk values"
https://www.living-learning.com/faq/npk.htm
According to this website, a lower number represents a lower concentration of that nutrient in the fertilizer. Be sure to follow the application instructions on the particular fertilizer boxes so that you don't overdose and burn the plants!
https://www.living-learning.com/faq/npk.htm
According to this website, a lower number represents a lower concentration of that nutrient in the fertilizer. Be sure to follow the application instructions on the particular fertilizer boxes so that you don't overdose and burn the plants!
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thepassionatecook
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Try to get something under 15 points in each category. Man-made chemical fertilizers usually have higher numbers than this and are not necessarily better. Organic fertilizers are beneficial in many more ways than simply growing the plant.
Having two types, such as a 4-2-4 and a 2-6-4 would be wise since most plants require more or less nitrogen and/or phosphorous at different life stages. An organic, liquid high nitrogen fertilizer would work well initially (promotes lush, green foilage). You should then switch to an organic, slow-release or liquid fertilizer when the plant is ready to bloom (if that's what you're after).
Shop for hydrolyzed fish fertilizer, seaweed/kelp, or other organic liquid fertilizers, such as Aggrand's organic product line. An alternative to this would be to simply use well-made compost. It should contain all of the nutrients you need. You can still add seaweed/kelp to compost for extra benefits.
N-P-K = Nitrogen-Phosphorous-Potassium
Having two types, such as a 4-2-4 and a 2-6-4 would be wise since most plants require more or less nitrogen and/or phosphorous at different life stages. An organic, liquid high nitrogen fertilizer would work well initially (promotes lush, green foilage). You should then switch to an organic, slow-release or liquid fertilizer when the plant is ready to bloom (if that's what you're after).
Shop for hydrolyzed fish fertilizer, seaweed/kelp, or other organic liquid fertilizers, such as Aggrand's organic product line. An alternative to this would be to simply use well-made compost. It should contain all of the nutrients you need. You can still add seaweed/kelp to compost for extra benefits.
N-P-K = Nitrogen-Phosphorous-Potassium
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The Helpful Gardener
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I'd say the best answer is to start ignoring NPK values for organic fertilizer. If you are interested in a big number, just use the chemicals. BUt the numbers don't tell you the method of action. In a chemical fertilizer, it is made from ammonia salts which burn fungii and dessicate protozoa, which where how the organic system was working before we invented fertilizer (well, we were actually inventing explosives, but at the end of WWI, there was a lot of explosives left around, and they wanted to get payed for them 
). The organic system is not trying to supply the nitrogen right to the plant, it is feeding appropriate soil biologies (already there or being supplied by composts). Bacteria are highly nitrogenic, fungal side is more phosphorus and potassium is usually from parent material (rock and soil) although we can get there with ash if we need to.
NPK is a bunch of baloney, cooked up by fertilizer folk to sell their wares. "Look, a big number" (that wipes out the fungal side that was supporting your root system, so the soil begins to compact, the bacteria that the fungus were supporting start to die (some of them were the phosphorus solubilizing bacteria that were making the phosphorus from the fungus plant available). Soon even the bacteria are having trouble with the second and third dose of fertilizer as the salts begin to accumulate in the soils (in drier climes; in wet ones the water soluble fertilizer is running both the phosphorus and nitrogen into surface waters and deeper, where the phosphorus causes algal blooms in fresh while the nitrogen waits until it gets to sea water, where it causes coastal dead zones). Organics locks the nitrogen in bacteria, the phophorus in fungii, and it releases it all in a slow and methodical method over MUCH longer stretches of time AS THE PLANT NEEDS IT. The chems need big numbers because the chems wash away and are in contact with the roots for very little time. The plant ATTRACTS bacteria and fungii with root exudates and ATTACHES them onto itself; it actually KEEPS the fertilizers around it. THAT's whay you can't compare organic and chemical fertilizer assays; it's meaningless. Two ENTIRELY different systems... You don't need big numbers, you need healthy soil!
So what do I use NPK numbers for? To tell how much damage you are going to do to your soil. Sure you still want big numbers?
HG
). The organic system is not trying to supply the nitrogen right to the plant, it is feeding appropriate soil biologies (already there or being supplied by composts). Bacteria are highly nitrogenic, fungal side is more phosphorus and potassium is usually from parent material (rock and soil) although we can get there with ash if we need to.NPK is a bunch of baloney, cooked up by fertilizer folk to sell their wares. "Look, a big number" (that wipes out the fungal side that was supporting your root system, so the soil begins to compact, the bacteria that the fungus were supporting start to die (some of them were the phosphorus solubilizing bacteria that were making the phosphorus from the fungus plant available). Soon even the bacteria are having trouble with the second and third dose of fertilizer as the salts begin to accumulate in the soils (in drier climes; in wet ones the water soluble fertilizer is running both the phosphorus and nitrogen into surface waters and deeper, where the phosphorus causes algal blooms in fresh while the nitrogen waits until it gets to sea water, where it causes coastal dead zones). Organics locks the nitrogen in bacteria, the phophorus in fungii, and it releases it all in a slow and methodical method over MUCH longer stretches of time AS THE PLANT NEEDS IT. The chems need big numbers because the chems wash away and are in contact with the roots for very little time. The plant ATTRACTS bacteria and fungii with root exudates and ATTACHES them onto itself; it actually KEEPS the fertilizers around it. THAT's whay you can't compare organic and chemical fertilizer assays; it's meaningless. Two ENTIRELY different systems... You don't need big numbers, you need healthy soil!
So what do I use NPK numbers for? To tell how much damage you are going to do to your soil. Sure you still want big numbers?
HG
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gixxerific
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The Helpful Gardener
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Thanks Gixx!
Many of you are probably wondering about this fertilizer assay "Wadaya mean, HG? A bigger number means more nutrient; says so right here opnn the package." " Well that's true in a most literal way. But it 's the mode of action and HOW the plant derives nutrition from the fertilizer. The chemical way is to put the nutrient in a directed form in contact with roots. But it is a salt, and water soluble, so it dries out other things as the soil dries, and when the soil gets wet, it migrates away from the roots; nothing to hold it in place. NOW you have compromised the biology that WAS feeding the plant and left nothing in it's place.
Those "low" assay organic fertilizers are not so much food for plants as food for organisms. We are feeding the biology in the soil and THAT feeds the plants (which is why poop works so well). These organisms bring nitrogen and phosphorus to the table, but remember what V'ger called everything on Earth in the first Star Trek movie? (Yes, guilty
) "Carbon based life forms". Thats EVERYTHING on earth. What's the most important thing about carbon? (as all good climate change students know). It is usually not very soluble. Like not at all. Try to dissolve charcoal. Or coal. Or a diamond. All pretty pure carbon. Now what about our bacteria? 5:1 carbon to nitrogen (C2N). And that's the high NITROGEN end of the life scale. We are in the low thirties; trees can be 100:1 C2N. Bacteria won't dissolve. And they don't wash away either. They exude polysaccharides (simple sugars )to make a glue that sticks them really well. Speaking of which, most of our plants exude the same polysaccharides to attract bacteria (Elaine Ingham calls it "cake and cookies" because that's how much the bacteria like it), which attracts protozoa, etc., etc... SO those low assay organic fertilizers get eaten by soil biology (bacteria and fungii) which puts the nitrogen in a carbonized state, and then it is released as it moves up the food chain from the 5:1 C2N bacteria, to the 30:1 protozoa, to the 100:1 nematode. Every step sequesters carbon, releasing small available amounts of nutrient where? Right around the "cake and cookies"; the plants root exudates! So even though the assay is lower, organics puts the nutrients where it counts, every time, while sequestering carbon in more and more stable forms. The chemical way constantly kills huge quantiities of biology, releasing nutrients and carbon to systems that can't store it biologically, so most of it volatizes (nitrogen as ammonia and carbon as CO2). And THAT'S one BIG reason why Gixx is right about better for the planet. Organics sequesters carbon, chemicals releases huge amounts, both in production AND use...
HG
Many of you are probably wondering about this fertilizer assay "Wadaya mean, HG? A bigger number means more nutrient; says so right here opnn the package." " Well that's true in a most literal way. But it 's the mode of action and HOW the plant derives nutrition from the fertilizer. The chemical way is to put the nutrient in a directed form in contact with roots. But it is a salt, and water soluble, so it dries out other things as the soil dries, and when the soil gets wet, it migrates away from the roots; nothing to hold it in place. NOW you have compromised the biology that WAS feeding the plant and left nothing in it's place.
Those "low" assay organic fertilizers are not so much food for plants as food for organisms. We are feeding the biology in the soil and THAT feeds the plants (which is why poop works so well). These organisms bring nitrogen and phosphorus to the table, but remember what V'ger called everything on Earth in the first Star Trek movie? (Yes, guilty
) "Carbon based life forms". Thats EVERYTHING on earth. What's the most important thing about carbon? (as all good climate change students know). It is usually not very soluble. Like not at all. Try to dissolve charcoal. Or coal. Or a diamond. All pretty pure carbon. Now what about our bacteria? 5:1 carbon to nitrogen (C2N). And that's the high NITROGEN end of the life scale. We are in the low thirties; trees can be 100:1 C2N. Bacteria won't dissolve. And they don't wash away either. They exude polysaccharides (simple sugars )to make a glue that sticks them really well. Speaking of which, most of our plants exude the same polysaccharides to attract bacteria (Elaine Ingham calls it "cake and cookies" because that's how much the bacteria like it), which attracts protozoa, etc., etc... SO those low assay organic fertilizers get eaten by soil biology (bacteria and fungii) which puts the nitrogen in a carbonized state, and then it is released as it moves up the food chain from the 5:1 C2N bacteria, to the 30:1 protozoa, to the 100:1 nematode. Every step sequesters carbon, releasing small available amounts of nutrient where? Right around the "cake and cookies"; the plants root exudates! So even though the assay is lower, organics puts the nutrients where it counts, every time, while sequestering carbon in more and more stable forms. The chemical way constantly kills huge quantiities of biology, releasing nutrients and carbon to systems that can't store it biologically, so most of it volatizes (nitrogen as ammonia and carbon as CO2). And THAT'S one BIG reason why Gixx is right about better for the planet. Organics sequesters carbon, chemicals releases huge amounts, both in production AND use...HG
Last edited by The Helpful Gardener on Fri Oct 02, 2009 5:58 pm, edited 4 times in total.
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gixxerific
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Really is there anything you don't know Scott? I would have said something like that but....you do it so much better 
Maybe a bit off topic but talking about carbon here is a link to series of short vids that opened my eyes to the reality of carbon and it's destructive properties. Though it means well, carbon that is, we are actually killing ourselves and the earth with it. Well let me put it this way the earth is not dying just changing in a way that will make us die. Only a matter of time, albeit a long time. If interested check these vids out they are pretty cool and informative.
https://www.npr.org/news/specials/climate/video/
Maybe a bit off topic but talking about carbon here is a link to series of short vids that opened my eyes to the reality of carbon and it's destructive properties. Though it means well, carbon that is, we are actually killing ourselves and the earth with it. Well let me put it this way the earth is not dying just changing in a way that will make us die. Only a matter of time, albeit a long time. If interested check these vids out they are pretty cool and informative.
https://www.npr.org/news/specials/climate/video/
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top_dollar_bread
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, thanks for sharing