Not offhand. You would look for organic fertilizers with this ratio: 1-4-4, close to one including bone meal and kelp. Applying six times the volume or weight would equal to some extent 6-24-24.

You haven't specified percent soluble. Many organic fertilizers act as slow-release ones, requiring actions of microorganisms to release nutrients in more "soluble" forms.

What does NPK have to do with organic gardening? If you need fertilizer, apply organic fertilizer at the recommended rate of 10-20 pounds per 1,000 square feet. NPK is a chemical concept, not an organic one. I suppose if you want to have the biggest and best flowers, you could optimize your fertilizer by adding bone and kelp as marshallz10 has suggested. We get plenty of flowers with monthly apps of alfalfa pellets, but maybe we could get more by doing what you're doing.

Ummmm So youre saying that organic ferts are not analyzed to be NPK??? All the ones I have seen even the ORMI listed ferts have a NPK rating.

In order to pass the government labeling standards, a fertilizer has to list NPK. This goes back to truth in labeling to keep people from loading a bag with sand and calling it fertilizer. Obviously the chemical fertilizer industry heavily influenced the legislators who wrote the rules. Back then much less was understood about the soil so, well, we have what we have.

What I'm saying is now that we know there are about 100,000 more species in the soil than was understood prior to the 1990s, and we know more about how they interact, we can use that knowledge to move forward without the government regulators changing the labeling.

What I usually tell noobs to organic gardening is that they have to forget most of what they have learned in school, from the chemical suppliers, and from government sources. You have to forget about NPK, chemical fertilizers, chemical insecticides, chemical fungicides, and chemical herbicides. When you have a problem in the garden (aphids, disease, weeds, etc.) instead of thinking "what do I need to kill," think in terms of what do I need to feed the beneficial microbes and insects. This is a complete reversal of the way the chemical industry would have you think. Healthy beneficial critters will control the pathogens and problem critters. The health of the beneficials improves when you feed them food and water. Organic fertilizer is made from food, not chemicals.

In the case of organic fertilizer, the concept of NPK is meaningless. Animal feed has to list protein and the sources of protein. That's the way organic fertilizer should be labeled. It is even more meaningless when you consider that some microbes have the ability to absorb nitrogen from the air and make protein. So if you started with 10 pounds of nitrogen (in the form of protein), you might end up with 15 pounds after the soil microbes finish with it. Those microbes also have the ability to extract P and K from the minerals already in the soil. So the point is chemical measures of fertility don't mean anything to the microbes in an organic program.

You will not find an organic fertilizer with those numbers. To get an analyses that high requires synthetic material be put in the mix.

What does NPK have to do with organic gardening?

Depending on one's preferences, a lot :)

It tends to be the way gardeners first get into organics by taking the conventional approach and substituting organic stuff for synthetic stuff.

Don't see anything wrong with it myself, especially when one is working with a soil that hasn't seen much organic matter introduced over the years.

Anyway, for the OP, I think you will find most compost not made from manures or mushroom compost to fit the bill. They tend to be low in nitrogen and I suspect that is what you are looking for?

Once again, justaguy presents a most reasonable explanation :-) NPK has a LOT to do with organics - as these are the primary plant nutrients, their availability or lack thereof is just as relevant to organic gardening as it is to non-organic methods. That's why soil tests outline the availability of these elements as well as all the necessary micronutrients and trace elements. And we need to move away from referring to non-organic tools as chemical products - ALL fertilizers are chemical in nature. The issue is whether the chemicals they provide are derived from natural (organic) sources or synthesized from other, typically petrochemical, sources.

What tends to get overlooked in this forum is that organic fertilizers are available in various presentations. While many posters adhere to animal feeds as a primary source, commercially prepared blended organic formulations are also available and in increasing numbers. And many gardeners, especially those with smaller plots or those focusing on ornamental landscape plantings, find these products enormously convenient and easy to use. Not everyone has the inclination to be an amateur chemist at home and these types of products eliminate any guesswork. These will have the same NPK labelling as any synthetic fertilizer product and have just as much relevance - know what your soil and therefore your plants lack (soil tests!) and apply as necessary.

FWIW, because of their low nutrient concentrations compared to synthetic ferts, organic fertilizers will have much lower NPK numbers. A general rule of thumb for organically derived fertilizers is that the NPK numbers will add up to 20 or less.

Justaguy makes another excellent point in that routinely using compost will provide pretty much all the nutrient requirements your plants need and in appropriate concentrations. Many folks who use compost as a mulch or soil amendment on a regular basis find they do not require any supplemental fertilization from any source.

Maybe the problem here is the definition of organic fertilizer? People have said that organic ferts will not have and NPK rating , however the ferts listed on ORMI have and NPK rating associated with them, so I dont know what more to say about this. If it is the definition that is in question lets say compost is concidered organic ferts, then i guess on could say that it doesnt have an NPK rating, but i bet if you send it out for a soil study it would come back with a NPK rating, dont you think?

Or maybe the NPK is a way to compair the chemical gardening with the nutrients needed for organics, I dont know this and this is why i post the question to you guys, but now the can is open and there are worms all over the place LOL.

The 6-24-24 was quoted because an areticale written states taht this would be the best combination for ferts for potatoes. Now i do understand that a garden or even a farm with plenty of organic matter, compost and such is a great asset. however to get there takes years or a lot of compost, out of my reach. So i need some reference to start. I think it was marshall that stated you can get a 1-4-4 and apply six times as much to get to a 6-24-24. is this right or is kimmsr right that even if you aplly that much you cannot get to the level of 6-24-24?

Thanks for reading my long winded confusion.

Kimms' point was that no commercial "organic" product could contain 24 percent Potassium or Phosphorous. To apply that much nutrients would require much more weight of material/per land unit.

I still want to stress the issue of solubility in organic fertilizers. NPK represents the potential availability, whereas the material immediately available might be just a few percentage of amount applied. Conventional fertilizers are usually made up of highly soluble salts containing the desired and rated nutrients. These are often immediately available or become sone available once chemically altered in the soil.

gardengal: I really want to like you, and I always expect you to already know this. I realize it's tedious to read a line by line reply but I don't see another way around it here.

Once again, justaguy presents a most reasonable explanation :-) NPK has a LOT to do with organics - as these are the primary plant nutrients, their availability or lack thereof is just as relevant to organic gardening as it is to non-organic methods. That's why soil tests outline the availability of these elements as well as all the necessary micronutrients and trace elements.

I disagree. Organic fertilizers do not feed the plants. They feed soil microbes and they eat food, not NPK. It is a different mind set. Soil tests limit their analysis to chemicals because they only do a chemical analysis. And they do that because the soil test techniques were developed a hundred years before the soil scientists knew there were 100,000 species of microbes living in the soil.

And we need to move away from referring to non-organic tools as chemical products - ALL fertilizers are chemical in nature.

I strongly disagree. Organic fertilizers are not chemical in nature, they are food. They are edible. They are good for us. If organic fertilizers are chemicals, please give us the chemical formula for corn. And please explain why we can't eat fertilizer ourselves and grow strong bodies and bones.

The issue is whether the chemicals they provide are derived from natural (organic) sources or synthesized from other, typically petrochemical, sources.

This is not an issue if we're already talking about organic fertilizers. But to believe this is an issue is to not understand the soil. Microbe food is food. Chemicals are not food.

What tends to get overlooked in this forum is that organic fertilizers are available in various presentations. While many posters adhere to animal feeds as a primary source, commercially prepared blended organic formulations are also available and in increasing numbers.

You overlooked the fact that commercially blended formulations consist of animal feeds. In other words you get animal feeds in a plain brown bag or you get animal feeds in a fancy bag.

And many gardeners, especially those with smaller plots or those focusing on ornamental landscape plantings, find these products enormously convenient and easy to use. Not everyone has the inclination to be an amateur chemist at home and these types of products eliminate any guesswork.

It only eliminates guesswork in chemical fertilizers, but it enormously complicates gardening. This entire thread is about finding a very specific combination of NPK numbers. What is the gardener supposed to do if he cannot find them? Those who take their organic gardening hobby more seriously, will learn that NPK does not mean anything to the microbes. All the gardener need learn is that soybean meal has more protein than corn gluten meal has more protein than alfalfa has more protein than ordinary corn and coffee. It is also important to understand that while feather meal is very high in protein, it is not very available for the first few months it's on the soil. Blood is so extremely available that too much can burn roots in a few hours.

These will have the same NPK labelling as any synthetic fertilizer product and have just as much relevance - know what your soil and therefore your plants lack (soil tests!) and apply as necessary.

Only the commercially bagged fertilizers will have NPK. The plain brown bags of animal feed will list protein content. If you want to test your soil chemistry, you can do that at any ag extension service. But you mentioned knowing what your plants lack. This is an entirely different test. This is what surprises me about you. You equate the two and they are absolutely not equal. What the plant needs and what the soil consists of are entirely different. My soil has tons of iron but my grass suffers from iron deficiency. Every soil test will tell me there's too much iron but a plant test tells me it's deficient. I know of one lab in the world that does that testing. There must be more, but the Texas Plant and Soil Lab is the only one I know.

FWIW, because of their low nutrient concentrations compared to synthetic ferts, organic fertilizers will have much lower NPK numbers. A general rule of thumb for organically derived fertilizers is that the NPK numbers will add up to 20 or less.

There is no way to compare purified and concentrated chemical fertilizers with organic fertilizers. The best you can do is forget about NPK and start over.

Justaguy makes another excellent point in that routinely using compost will provide pretty much all the nutrient requirements your plants need and in appropriate concentrations.

Justaguy did not say that so I will not hold him to it.

Many folks who use compost as a mulch or soil amendment on a regular basis find they do not require any supplemental fertilization from any source.

kimmsr is one such person. I would suggest that the validity of that statement seriously depends on your soil. My soil is limestone rubble with sand on top. There is no clay or loam. My grass yellows and thins out, my flowers never bloom, and I don't get any lemons or tomatoes unless I use fertilizer.

slacker:
Maybe the problem here is the definition of organic fertilizer? People have said that organic ferts will not have and NPK rating ,

Maybe you read that somewhere else. I said just the opposite above.

If it is the definition that is in question lets say compost is concidered organic ferts,

No. It is not considered an organic fertilizer. That is why it is not sold as fertilizer but as compost.

then i guess on could say that it doesnt have an NPK rating, but i bet if you send it out for a soil study it would come back with a NPK rating, dont you think?

Anything you send out for a soil test will come back with the amounts of N, P, and K. That includes steel, rubber, wood, aluminum, glass, etc. NPK is what they're looking for. In organic gardening we are concerned with the healthy population balance between beneficial microbes and pathogenic microbes (and protozoa and microarthropods). If you send these materials out for a microbiological study, you will not find the hundred thousand species of soil microbes. But if you send compost out for such a test it will return with high populations of those microbes.

I've tried to come up with different analogies as to how the microbes in soil work. How about this. One thing many of us agree on is that mammal urine will provide additional fertility to the soil. Consider this: microbes don't urinate but they do shed waste materials. Not all of those waste materials are effective plant food but there are 100,000 species giving off waste materials. Apparently some of those species are extremely effective in giving off plant food. So if you think of thousands of species urinating in your soil 24/7, does that help explain how the soil microbes work? But they have to be well fed first and that means they need to eat food like grain or animal protein, carbohydrate, vitamins, enzymes, and minerals.

Ok first let me say I dont mean to anger anyone here , I am just trying to learn. So instead of an NPK rating for organic ferts, it would be better to get a microbiological count?

If this is true how could one convert what has been done in the past (right or wrong) to what you soil would need? I dont think i said that right. let me try again

If the soil, which we know, needs microbes to work right, what tests are done to show what microbes are lacking, then once we know what is lacking where would we go to find out how to replace what is lacking.

do they have a soil test to see what microbes are lacking.

Your point above about the urinating microbes is very well done, and sometimes I do need things explain like I am 2 , until I get it.

thanks again guys/gals

Well done, dschall_s_a. I do, however, try to figure out the relative balances of primary and secondary nutrients of bagged "organic fertilizers" I might apply. Different plants prefer different ratios among the nutrients. That said, most of plant nutrition is ultimately derived from applications finished compost and decaying plant roots and other soil life.

Soil microbial and fungal life depend upon the quantity and qualities of organic materials first and in elements and molecules of nutrient value available in solution or weakly bonded to soil particles and rootlets.

So let me get this right then, from everything you guys are saying and what i have been reading on the web, the best thing i can put in my garden to get the best veggies are ........wait for it ...........WORM CASTINGS??????

what ya think?

You can get biology tests done, and the people who perform/sell the tests swear by them, but I think you can avoid that cost. These 100,000 species of microbes have only been identified by their DNA remains in the soil. Relatively nothing is known of their purpose in life. Prior to these DNA revelations it was thought there might be 50 species of microbes even though only about a dozen could be found in petri dishes. And even if there were 50, scientists could not reconcile all the different effects found in the soil from a mere 50 species. Once the first 30,000 species were discovered in the 90s, all that changed. Even without knowing the individual contribution of individual species they could speculate that somewhere in these vast numbers of species that all the unexplained effects found in the soil would eventually be found. Chemistry could not explain, for example, how the soil helped protect plants from the known disease causing microbes in the soil. 50 species of microbes could not do it either. But 30,000 and then 100,000 species of microbes probably allows it to happen.

Compost is the most accepted way to get the microbes into your soil. I just assume I have the microbes after all this time of not using chemicals in the garden and start feeding. That's what I usually suggest to people. It is sort of like, 'feed them and they will come.'

The folks at the Soil Foodweb will test your compost tea and tell you how good that is. As a homeowner I would not spend the money. If I was making compost tea professionally or if I was applying it on a farm I would have it tested.

Worm castings is compost made from worm dung. As I understand it the decomposition takes place outside the worm pretty fast, so it's ready to use when you get it. But I don't think it's the best thing you can use. I think real fertilizer (food) is the best thing you can use. Modern organic fertilizers are made from seed grains (like soy, corn, alfalfa, wheat, cottonseed), seaweed, and sometimes animal protein. If you just add worm castings you'll get more microbes but not that much more food. If you apply food (and water) you'll get a huge population increase of the microbes already in the soil. I like to use ordinary corn meal from the local feed store. Corn is one of the lowest protein content grains but it has the property of eradicating disease and I have problems with that. My first alternate is alfalfa pellets. The application rate I use on my lawn is 10-20 pounds per 1,000 square feet on all the national holidays. If I am fertilizing individual small plants then I scatter a heaping handful under the canopy of each plant monthly. For my lemon tree I scatter two heaping handfuls. It's not very big (hoping to keep is pruned back). Alfalfa really works better than corn for plants for me. The first time I used it on the lemon I got three inches of growth in 3 weeks.

Aside from there is no organic fertilizer with those numbers why do you think you need to apply something like that? Have you had a good, reliable soil test done? A soil test for NPK and soil pH is one tool an organic gardener/farmer has available along with those other simple soil tests I have outlined numerous times here. The soil is the single most important part of the organic gardeners/farmers garden or farm, and knowing what kind of soil you have and what is in it, and what might be needed is part of that.

Slacker,

Let me see if I can reconcile what you have been reading.

First, you won't find any organic fertilizer labeled 6-24-24 because organics do not contain nutrients in that high an amount. Getting 24% of a material to contain a nutrient requires synthetics.

You can get a fertilizer labeled 1-4-4 and get the same results. It is the same ratio of primary nutrients as 6-24-24. Can you use 6 times the amount? That's tricky. Nutrient content is expressed by weight. 1-4-4 means 9% of the material, by weight is nutrients. Because the synthetic fertilizer with a 6-24-24 rating will likely have a different weight than the organic one with 1-4-4 rating amount to use is not directly comparable. Most pre packaged ferts come with label instructions to assist you in determining proper quantity though so not a big deal.

In terms of whether organics are fertilizers or not really depends on your mindset. Synthetics do not feed the soil, they feed the plants directly by requiring no processing by soil organisms. This is what many regard as a fertilizer.

Organics do not feed plants directly because the nutrients are 'locked up' in the organic matter. The soil critters process the organic matter and one of the end results is the release of nutrients plants can use. For this reason some do not refer to organics as fertilizers, but some do.

The NPK rating on organic ferts is deceptive. As was noted previously the actual amount of nutrients made available from organic matter in the soil may differ due to the soil critter activity. It's the federal laws requiring the labeling that result in this, but not much can really be done about it (and I prefer truth in labeling laws in most cases anyway).

For your potatos or any other crop really, if you are working in a new soil I would advise adding a good amount of compost (1-2" per 6" of soil growing depth) and seeing how it goes. I would also get a soil test done to get an idea of your soil's characteristics. Anyone who makes a blanket recommendation for a specific fertilizer ratio for a plant is not taking into account the soil the plant is being grown in.

In the traditional, commercial agriculture business such recommendations make a little more sense because the farming soil is largely infertile and therefore adding synthetic nutrients in the proper ratio makes sense for the plant, but in most gardening soils there is already a baseline level of fertility and fertilizers should only be applied to make up for what isn't already there. A soil test will help you understand what is there, what isn't there, what is perhaps there at elevated levels, etc.

For organic gardening simply adding organic matter regularly is the default approach. For some with soils that hold onto nutrients well this is all that is ever needed for most plants, but for some with very rocky or sandy soils it may not be enough and so some type of fertilizer, organic or synthetic will be required for optimal plant growth.

I agree with most of what justaguy2 writes above. I do disagrees with "simply adding organic matter regularly is the default approach." Two points:

In natural ecosystems of relatively high "productivity", organic matter is added to or on soil at regular intervals, so to speak. I suppose this is the "default model."

The nutritive value of compost changes with time. At least in my subtropical area, the half-life of compost is about a year in garden/farm settings. The rate of decomposition will vary with climate and frequency of soil disturbance. After about 2 or 3 years of compost applications, the rate of release of nutrients from decomposing composting reaches of steady state, varying with soil temperature.

Based on my experience on my ground, nutrient availability peaks when soil temperature reaches the lower 60 degreesF. The tipping points seem to relate to a change over from fungal dominated soil condition to bacterial activity at warmer temperatures. That's my guess.

I forgot to mention that applications of chemical Nitrogen from any souce tends to accelerate decomposition of compost. The release peaks in 6-12 weeks after fertilization.

ok so there is no direct correlation between NPK and organic gardening. The best you can do is support the soil? so adding compost, worm castings, anything else?

what would be bad for the microbes? is there anything that should not be put in the soil that might harm the little guys?

Anything else that the little guys might really like to make them more active or the population larger?

Thanks guys this has been a real eye opening experience.

I'd caution against excessive focus on soil micro-organisms. Sure, you can add molasses or other simple carbs to accelerate microbial populations but, remember, not all soil microbes are beneficial in large populations. I focus on organic content of the soil and good aeration. I avoid excessive soil working because this activity stimulates microbial denitrification.

Remember that good compost and resulting gel-like organic coatings of soil particles improve both the moisture-holding capacity and nutrient-holding capacity of the soil. Organic material helps build good soil structure, binding small soil particles into larger semi-stable "peds" and improving both drainage and aeration.

Adding salt fertilizers tend to reduce these advantages.

dchall, I want to like you too :-) However, sometimes I think we get so focused on our viewpoints and way of doing things, we lose track of the bigger picture. I am not sure we are that far apart in our thinking, although because of my training, perhaps I tend to look at things in a very generalized approach. Let me see if I can explain myself more to your satisfaction.

I dislike being pedantic but I feel the need to go back to square one - Chemistry 101 :-) Chemical elements are the building blocks of the universe - everything has a chemical basis, including corn. I'm sure you've heard of the term 'organic chemistry'. This is defined as the "discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds consisting primarily of carbon and hydrogen, which may contain any number of other elements, including nitrogen, oxygen, the halogens as well as phosphorus, silicon and sulfur." (from Wikipedia) Carbon and hydrogen define the primary chemical compounds of ALL living things. They define us as humans (yes, we have a complex chemical composition as well). And last I checked, corn is or once was a living thing :-)

In response to my statement that ALL fertilizers are based on chemicals, you said this:
Organic fertilizers are not chemical in nature, they are food. They are edible. They are good for us. If organic fertilizers are chemicals, please give us the chemical formula for corn. And please explain why we can't eat fertilizer ourselves and grow strong bodies and bones.

See above :-) You are over-simplifying. In their raw state, organic fertilizers may be food. But they are also chemicals, naturally occurring complex chemical compounds. There most certainly is a chemical compound that defines corn, that makes it unique from any other grain or meal or food source. It's long and involved and I certainly don't have the sophistication or knowledge of organic chemistry to repeat or analyze it but it exists. And don't be silly with the question about why humans don't eat fertilizer - c'mon, that's below you :-) Obviously, the human metabolic system and how we receive and process necessary nutrients is vastly different from that of plants - about the only thing we have in common is that both plants and humans (and all other living things) do have specific nutrient requirements that must be satisfied for good health. And if all organic fertilizers are "food", are "edible" and are "good for us", then how come we don't snack on say.....bone meal or cottonseed meal, for example? Over-simplification again.

Organic fertilizers do not feed the plants. They feed soil microbes and they eat food, not NPK.

Now where in my statement did I say that organic fertilizers feed plants? NO fertilizer regardless of source "feeds" plants - plants manufacture their own "food" through the process of photosynthesis. The only thing that fertilizers do is present essential plant nutrients which the plants use to facilitate photosynthesis and which get converted during that process to the necessary proteins, starches and sugars - the actual plant "food". Whether these nutrients - the NPK and others - are made available through the conversion of material by the soil organisms - organic matter in the soil, compost or other applied OM, organic fertilizers - or are directly available via soluble synthetic fertilizers is irrelevant to the plant. Any plant will still require NPK (and various other micronutrients and trace elements) in order to complete its biological functions.

And not all soil microbes eat "food" or at least what you are terming "food" in the manner of organic animal feeds/meals. Some species of fungi digest minerals and convert them into phosphorus, potassium, calcium, magnesium, iron and other trace elements. Other microbes eat their cousins or more often, their cousins' excrement. Others are able to live off atmospheric nitrogen, which is about as basic a chemical element as you can get.

In response to my statement regarding the only difference between organic and synthetic fertilzers is the source of their chemical basis, you said:
This is not an issue if we're already talking about organic fertilizers. But to believe this is an issue is to not understand the soil. Microbe food is food. Chemicals are not food.

I understand the soil perfectly. And I also understand the intricate relationship between soil organisms and plants. And I understand plant biology and know exactly how plants access the soil for the chemical nutrients they need to accomplish photosynthesis, generate food and complete their life cycle. Chemicals may not be 'food' on a stand alone basis but they are the building blocks of food. To ignore this very basic fact of life is to indicate a serious lack of understanding of the physical world. You can concentrate on the soil and the soil microbes all you want but unless these are supplying, and in adequate concentrations, all the necessary plant chemical nutrients - there's that NPK again - you will have distressed, unhealthy plants.

Commercially prepared blended organic fertilizers are not simply animal feed or meals. They are for the most part animal and plant by-products (which could include feeds or meals) but they also include naturally occurring minerals as well. You may get soybean or alfalfa meal in plain brown bag but the fancy bag of blended organic fertilizers could have cottonseed meal, fish bone meal, alfalfa meal, feather meal, soybean meal, mined potassium sulfate, kelp meal, seaweed extract and soft rock phosphate.

Why using prepared, blended organic fertilizers should enormously complicate gardening is a bit of a mystery to me. If one understands plant nutrient requirements and the relevance of NPK ratios, why is it such a jump to translate a desired NPK of 6-24-24 to a formulation that is similar to 1-4-4? Or any similar low nitrogen, higher phosphorus and potassium blend? And because organic fertilizers deliver their nutrient content via the actions of the soil organisms, it is much harder to over-fertilize (compared to synthetics) as the presentation is over time and the plant will only absorb the nutrients it requires. So reproducing an exact NPK ratio is far less critial with organic fertilizers than it is with synthetics.

What the soil lacks in nutrients will be directly evidenced by the plants, so the two are intrinsically entwined. One of the reasons soil tests are done are because plants display nutrient deficiencies and the tests will address what specifically is lacking. There are other factors involved, of course - I surmise the iron deficiency your lawn shows despite the iron concentrations in the soil tests is due to too high a soil pH making the iron unavailable. Which is why soil tests virtually always report pH as it has a huge bearing on how nutrients are accessed and utilized.

So I stand by all my statements, but primarily the one that emphasizes that NPK analysis is just as important for organic fertilizers as it is for synthetic fertilizers. And one can omit the reference to fertilizers altogether. Understanding plant growth, biological processes and the role soil microbes play in these processes and how these all factor into the need for plant nutrients is sufficient to clearly demonstrate that NPK (and all the other necessary micronutrients and trace elements) is just as significant a factor in organic gardening as it is in traditional, synthetically based gardening.

So yes, slacker, there IS a correlation between NPK and organic gardening - there is a correlation between NPK and gardening/farming/growing, period. The correlation is that plants require nutrients, primarily NPK, and in sufficient quantities that will vary during the course of their life cycle. Whether these nutrients are delivered via the soil and the soil microbes or pretty much instantly via soluble synthetic fertilizers is immaterial to the plants - nutrients are nutrients. That this is true is demonstrated by hydroponic growing - there are no soil organisms present because there is no soil, yet these plants will grow happily in any non-soil medium as long as they receive adequate nutrient input. Obviously in organic gardening there will be a much higher focus on the soil and the soil microbes as they are doing all the delivery work for nutrient presentation, but nutrient requirements will remain unchanged regardless of source.

Before applying any fertilizer from any source, it is important to know the chemical composition of your soil and what is lacking, adequate or present in excessive concentrations. And the only way to know that is by a soil test. Once you armed with this piece of vital information you can research the nutrients needs of the crops you intend to grow and supply what is lacking, if anything, or adjust for other variables. But knowing and understanding NPK is essential for that process.

gardengal: good piece. I still differ with you in some of the fundamentals.

I can't talk about chemistry alone. Biology is more important. Without getting religious about this, there is a difference between life and chemicals. You cannot make food starting out with bags of chemicals. Living creatures perform the miracles of arranging different kinds of food into the form of cells (containing protein and carbohydrates) but using vitamins, enzymes and minerals along the way.

Cells differ from chemicals arranged by oxidation or reduction in a lab. Genes produce hair (huge amount of protein but not available) and blood (huge amount of protein and highly available) as well as other plant and animal materials. You cannot even equate different organic materials in terms of NPK simply because of relative availability. Given that, how can you equate NPK between chemicals and food? Even if we knew the chemical composition of corn, we could not pile up bags of the chemical constituents and make something nutritional out of it. By simplifying organic gardening to NPK you are suggesting it is just that easy.

I understand the soil perfectly.
You must be the first one, because they have not identified the nature of about 99,000 of the microbe species in it (just funnin with you - please don't take offense, I know what you mean, but there is a point in there).

You can concentrate on the soil and the soil microbes all you want but unless these are supplying, and in adequate concentrations, all the necessary plant chemical nutrients - there's that NPK again - you will have distressed, unhealthy plants.

I'll try not to growl. It is not that simple. The microbes need food, not bags of NPK. When the microbes are well fed, so are the plants.

Why using prepared, blended organic fertilizers should enormously complicate gardening is a bit of a mystery to me. If one understands plant nutrient requirements and the relevance of NPK ratios, why is it such a jump to translate a desired NPK of 6-24-24 to a formulation that is similar to 1-4-4?

The context of my statement was with respect to chemical fertilizers, not organic. I'm not sure why the jump is hard but these questions show up all the time on these forums. Perhaps it's because they read articles in magazines where very specific NPK values are stated rather than giving similar information in more general terms.

So I stand by all my statements, but primarily the one that emphasizes that NPK analysis is just as important for organic fertilizers as it is for synthetic fertilizers. And one can omit the reference to fertilizers altogether. Understanding plant growth, biological processes and the role soil microbes play in these processes and how these all factor into the need for plant nutrients is sufficient to clearly demonstrate that NPK (and all the other necessary micronutrients and trace elements) is just as significant a factor in organic gardening as it is in traditional, synthetically based gardening.

I've already disagreed with this statement, so dwelling on it only looks argumentative. Suffice it to say two different organic fertilizers can have identical NPK numbers but one has no value due to the ingredients being indigestible in a practical time. Organic gardening is not about NPK.

Food is for animals .
Fertilizer is for plants .

Feed. Edible materials which are consumed by livestock for their nutritional value. Feed may be concentrates (grains) or roughages (hay, silage, fodder). The term, "feed," encompasses all agricultural commodities, including pasture ingested by livestock for nutritional purposes.

Fertilizer. A single or blended substance containing one or more recognized plant nutrient(s) which is used primarily for its plant nutrient content and which is designed for use or claimed to have value in promoting plant growth.

Organic matter. The remains, residues, or waste products of any organism.

Here is a link that might be useful: Definition of Terms Used in the National Organic Program

Fortunately in the non commercial world we're not hamstrung by governmental definitions. They have to define their terms so that unscrupulous operators don't bag sand and call it fertilizer. We can probably thank Billie Sol Estes for that.

Microbes are animals that require food. The stuff in organic fertilizer is not for plants. It is for the microbes. Thus it is food. If you want to call food feed, fine. I've seen the distinction clarified by calling it food grade corn and feed grade corn, but it's still corn. The ground up grains in organic fertilizer are identical to the flour(s) made from wheat, corn, soy, etc. and used for baking bread. The only difference is the level of care taken in storage is much higher when it is destined for use as people food. If you have some naming suggestions to clarify the distinction between fertilizer and the stuff used in organic fertilizer, you should speak up.

In my mind any definition of organic matter should absolutely include living creatures that are in continual production of waste products. Furthermore, milk and blood are not waste products but they make excellent food for microbes. Remains and waste products are only important inasmuch as they provide food for other living creatures including microbes and plants. It is the living creatures in the soil that are important. Without them we'd be standing on miles of dinosaur dung and carcasses. As I've said before, the soil borne microbes are the only organic matter that matters. It's not quite that simple, but they matter a lot more than the National Organic Program seems to think.

slacker: I wouldn't use anythig as powerful as the fertilizer your'e looking for. How about some soft rock phophate for the P (gives you Ca as well), some wood ash for the K, and growing legumes in your rotation for the N ? Regards, Peter.