One thing about compost is that a lot of its nutrients are part of its structure and are released slowly. So it may not measure up to its actual content.

Also how does this test work? Do you soak a sample of it in water and then do a color test, or what? If you are using water, what kind - tap or distilled? Is the (presumably dark) color of the extract interfering with the test color? Also how do you measure the amount of compost to be used?

What are you doing with all this compost? If you're putting it on plants where it belongs, how are the plants growing? The proof is in the pudding.

I have only tested my compost once and it was for a research study comparing store bought and home made compost, and I used a real lab. I can tell you home made is generally superior to most composts you can buy.

The home test is unreliable, and anyway the very act of composting loses typically half the nitrogen (and half the carbon, which is a worse outcome). No surprise here. If you want to keep your nitrogen, bury it.

The testing kit was recommended by the nursery where I got it (but of course they are making money off it's sales). It tests for pH, nitrogen, potassium & phosphorous. Each is tested separately by taking small quantities of soil (dried and sifted) and placing it in a test tube. Then different reacting agents are added to the tubes and mixed. Solids are left to settle, then removed and the resulting liquid is compared against a color chart to see if nutrient quantities are high, medium or low. So no water is added and I was careful to thoroughly clean all utensils before testing. Still, I did find it odd that nitrogen levels were so low in all the tests I did. As a control I tested a planting mix of finished compost, soil conditioner, coco coir and fish bone meal and that came back with medium nitrogen levels.

I've been applying compost all over the gardens, but it's a relatively small amount over a large area. Plants seem to respond well, but I have a lot more soil building to do. The soils were in pretty poor condition when we moved in (property was neglected for a couple years before we arrived). It did seem like many of my plants were a little slow growing last year but we did have some inconsistencies in irrigation that could be responsible for that.

I'll continue to apply compost in all my beds as I'm sure it is helping more than anything, but was just curious if anyone else had experience low nitrogen levels in their compost. Was also wondering if the excess of coffee grounds could be throwing things off somehow.

And yes, I agree it's time to send off some sample to a lab to get more accurate results.

thanks, but I am telling you that the nitrogen goes up in the atmosphere and gets lost. The higher the surface of the compostable, the more efficiently it gets lost. so you start with some OM which is a complete fertilizer, and at the end of the composting you end up with something incomplete.

What those soil tests are testing for is soluble, readily available, nutrients. The nutrients in compost are not very readily available, soluble, so they do not show very well in those tests. Compost is a slow release source of plant nutrients that need the activity of the Soil Food Web to release the nutrients and feed the plants.

During digestion some Nitrogen may be lost to the atmosphere, but if a lot is there would be a noticeable odor of ammonia.

kimmq is kimmsr

Your original post said that if anything you don't have enough browns to keep the ratio correct. In general this means an overabundance of N rather than a deficit. The only way that would lead to a nitrogen depleted product is if you had a lot of very slow digesting browns like wood, in which case the greens might go quickly and some N would be lost, followed by slower decomposition of the wood which could deplete N on the back end. But the browns you list are not woody, and you said your piles don't have an unpleasant odor, so you're not losing oodles of N.

One thing about N is that it's highly variable according to season, temperature and moisture content (i.e. rainfall) as well as absorption by plants during the growing season. In this way it is different from P, K and the micronutrients, which stick around a lot more and do not change as fast. So we don't get too hung up on it.

You might consider using some of those grounds as mulch, and cover with leaves, yard waste etc. so they don't get crusty and repel water. Spent grounds are not particularly acidic so don't worry about that. Degradable mulch will provide a good boost of nutrients (including N) directly to the soil and you can skip the composting step.

Soil tests - home or otherwise - will nearly always show deficient levels of N. And that's because of its volatility as described by tox above - it doesn't hang around long as a measurable or quantifiable item. In fact, many professional labs do not even test for N because of this reason - it will only show as a single snapshot in time, not as a measurable, ongoing source. And it will take different forms as well - atmospheric N - the largest source of N - is virtually unavailable to plants except for those leguminous types that are able to absorb N from the atmosphere and 'fix' it via their roots. Most plants rely on N in the form of nitrates or ammonium and these are not often volatized or lost to the atmosphere.

Maintaining a good balance between browns (carbon sources) and greens (N sources) in your home compost will reduce the loss of N via volatilization or leaching. Researchers report optimum values from 20
to 31 (a C:N ratio of 20 -31 C to 1 N). A majority of investigators believe that for C:N ratios above
30 there will be little loss of nitrogen. University of California
studies on materials with a initial C:N ratio varying from 20 to
78 and nitrogen contents varying from 0.52% to 1.74% indicate that
initial C:N ratio of 30 to 35 was optimum.

As tox said, just don't get hung up on N levels derived from any soil tests. They will not be accurate and will not reflect a true measure of plant available N. Any source of N rich organic matter - like home compost - will be a fine addition to the garden.

I was surprised when you said that you were worried that you did not have enough browns. To me, it sounded as though you might not have enough greens. I wonder if some lawn clippings (DOH! It's winter there, isn't it?) mixed in would greatly assist. I fine grass clippings are terrific when put into the pile and mixed in.

I have also heard that home pH test kits are fairly unreliable.

It is not so much that the home soil test kits are not very reliable as it is that they do not tell you what you really need to know. You do the soil pH test and the results tell you the soil has a pH of 5.7. Which lime, Calcitic or Dolomitic, do you apply and how much? Applying too little will not correct the problem and applying the wrong one will not correct the problem, and applying too much is a waste of your money and will create more problems by raising the soil pH too high which can result in nutrients being unavailable to the plants.

A TV show gardener has for years stated that he always throws a couple of handfuls of lime (does not say which kind) because the soil he gardens in is always acidic. That is because not enough, and maybe the right one, is not added to the soil to correct the problem.

kimmq is kimmsr

at any rate the pH varies rapidly with depth, often more than 1 unit per foot and 3 units per 3 ft, while changing from alk. to acid. The environment created by decomposing organic matter is always close to neutral. In my acid soil years ago, I would pile manure for the winter somewhere far from the garden (so voles would congregate there). In spring that spot would be covered with clover, otherwise absent in my backyard, which would then survive for years only there. Deep roots were apparently unaffected by the below ground acidity. It is a well known effect that holistic management types use to show the benefit of grazing (clover would grow in acid soils, where cow pies fell).

It occurred to me that a home test kit must be designed to measure one specific form of nitrogen, but which one? Nitrate, nitrite, ammonia, ? Even it was a good idea to worry about it (which I believe has been thoroughly addressed above), the test is probably not even measuring N in all its forms.

Your end product (low nitrogen) is exactly what would be expected if you started with a higher nitrogen ratio, and the compost pile got very hot. The high bacteria load would produce ammonia which would escape into the air.

If this were a soil mixture then there would be bacteria in the clay that could hold on to the nitrogen in the ammonia. (That is why large farms inject ammonia into the soil to add nitrogen.) However, without the clay and it's bacteria, the ammonia escapes the compost pile as gas. So the irony is that for all the nitrogen you began with, you end up with very little in the finished product.

The best solution is to add clay into the compost pile - maybe about 5%. That will introduce the needed bacteria (not to mention added minerals contained in the clay). As a secondary step, you might want to cut back a bit on the green materials - but the clay is a must.

at long last someone else who says these things, Richard. But pulverizing clay is easier said than done. It is still better to bury everything. In fact, I think that there are "all brown" cases where more nitrogen is available to the soil than in compost. consider dry leaves mulch. Earthworms pull them in, crunch them, regurgitate them, and let bacteria take over. Pronto, nitrogen fixed into the soil, two inches under, and immediately available to the plants. Compost? not so much.

Monibucky,

The aroma would be kind of a stinging smell like urine. It would be strongest when the pile was hot, but maybe undetectable otherwise. Chemically, the nitrogen is escaping - there is no getting around that.

That said, you still have a good result. The end product of composting is humus, which is not supposed to be fertilizer (i.e. nutrient dense). It provides the garden with organic material and soil biology. If you need nitrogen, add in a little alfalfa or feather meal and problem solved.

The bacteria, and other members of the Soil Food Web, do not live on the mineral components of soil, the clays, sands, and silts. They need the organic material that is another component of soil. Perhaps the Soil Biology Primer may help some here.

http://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/health/biology/

kimmq is kimmsr

While I support the idea of applying compostables directly to the soil, the idea that composting wastes virtually all the nutrient content is a bit overblown IMHO. I have not yet seen evidence to back that up (i.e. controlled studies) if it is out there. Admittedly, since I'm not directly in that profession, I don't keep an eye on the scientific literature. I just don't think composting is a complete waste of time, and sometimes it is the most practical alternative to landfilling (which we need to keep in mind is what most people are doing with a lot of their organics). Just sayin'.

at least for the carbon, which is the keystone nutrient, the evidence is plentiful. since your compostables are 80%+ carbon, all you need to do is measure the input weight and the output weight.

Carbon is not a plant nutrient although the Soil Food Web does convert what makes up that carbon into nutrients the plants can use.

kimmq is kimmsr

and yet soil scientists say that it is the keystone nutrient. since without it nothing becomes available. now do not run out and pour coal on your garden. It needs to be organic carbon. I made an example a few posts up how carbon produces nitrogen for example. Once you accept that biology dominates soil dynamics, carbon becomes the keystone.

Just my practical experience: The plants may outrun the available N from your compost at any given time.

Whether it leaches away or is lost to the atmosphere, or get used by the plants, I'll leave to the metaphysicians.

My point, simply, is that there is no guarantee that even a generous application of compost will supply the optimum level of N at all times through the growing season.

For one thing, what constitutes "finished" compost? I suppose convention would say a cooled pile that has been turned a couple of times that has had an ample supply of N and moisture during the cooking phase, + 6 weeks or so after that. But that's only a convention that experience teaches us means that the compost won't rob the soil of N by itself. The compost will continue to decompose afterwards, supplying N plus other nutrients. Just not necessarily at optimum levels at any given time.

Once I learned what I was doing back in the 1960's I have not had a problem with Nitrogen deficiency. Adequate quantities of organic matter, not necessarily large amounts of organic material, in the soil are the key. Even when the soil test came back with a note to spread 3 pounds of N per 1,000 square feet there was no problem with the plants growing and producing as they should.

Compost is one form of organic material that can be put in soil and it will be the catalyst for the buildup of the Soil Food Web. Get the amount of organic matter in the soil up to adequate levels, ie. make the soil good and healthy, and the plants will have enough nutrients in balance.

kimmq is kimmsr

I recently used a soil test kit and it stated that the mixed solution for the nitrogen test needed to be kept out of sunlight as this could alter results

I found the following at the link below, "Compost Application: It is a common misconception that you cannot add too much compost to your soils. In fact, excessive compost can create many problems. The most common problems are above optimum nutrient levels, high soluble salts, excessive organic matter, and soil pH levels that are either too high or too low. Soil organic matter, which provides many positive attributes to soils used for crop production, can be detrimental when used excessively. Compost is an excellent, albeit slow release, source of essential nutrients. When soil organic matter levels surpass 8%, it can lead to excessive nutrient availability and other problems."

On one hand compost has no nutrients but on the other hand too much comp-ost in the garden can create excessive nutrient levels. If too much organic matter in soils produces excess amounts of nutrients then those nutrients must be there in spite of what chemical tests indicate.

http://soiltest.umass.edu/fact-sheets/over-fertilization-soils-its-causes-effects-and-remediation

kimmq is kimmsr

it occurs to me that if you just added this compost to already existing soil, the nitrogen already present would have been adequate for the plants (unless the soil was truly poor), and the cause of the slow growth may have been the water issue. also, if you were adding phosphorus and potassium via the nitrogen-depleted compost, you may have had good root growth in the plants, which will stand them in good stead in your now nitrogenized soil.

This has been an informative thread, and ty, kimmq, for the link to the USDA soil biology site.

If you are lazy and want to watch a video on why excessive compost can have issues you can watch this video https://www.youtube.com/watch?v=M0KwZdE9YAY.

Compost, being generally low in nitrogen, is best with some legume crops that need a lot of P and K. The best organic way to provide N is underseed vegetables with clover. Failing that, there is always urea.

If compost is "generally low in Nitrogen" please explain how if too much is put into soils there can be excess Nitrogen.

kimmq is kimmsr

"The end product of composting (humus) is stripped of all N and P."

Except that most of the time we don't wait years for the 'end product' to form. We use compost while it's just beginning the long tailing out toward humus. And it does have nutrients, significant amounts. As a result, continual additions can over time increase nutrients to very high levels. I don't want people reading this thread to get the idea that compost has few nutrients. If you'd like to see my soil test results showing high to almost excessive P and K after adding pretty much nothing but compost for a few years, I can post a link. :-]

On a more general note it is mildly amusing to be told by posters here that I'm composting wrong if my piles aren't hot, and that I should have cold piles if I want nutrients in my compost, both within a week of each other.

All things in moderation...sometimes hot, sometimes cold, soil is great, garden is fine, plenty of nutrients. :-D

nitrogen might be the first to the party, but it gets partied out fast. Two ways to grow plants to just grow green-age above ground. Nitrogen! which everyone knows about, and Calcium! which most people neglect, because we have been programmed to fixate on nitrogen fertilizers. So#1 check for calcium, if you have plenty, you are good! 2# compost is not designed to fertilize as much as it is to improve soil texture , tilth, and increase you cation exchange capacity (how well you can hold fertilizing minerals-once you get them). #3 if you took a sample from the forest floor, it would have little to barely any stored up fertilizing minerals, but it has so much decaying organic matter that the humic acid constantly breaking down new food for plants (by the second) is feeding their mouths, the minute they open. #4 these tests are snapshots, they only show one step of the race, not the overall health of the runner

:)

Once again, compost tests low for Nitrogen because the N in compost is not readily available, it is not soluble, which is what soil tests look for, readily available nutrients.

For the most part we plunk down too much Nitrogen which results in nitrate poisoning of the water we drink, we are slowly poisoning ourselves. The high levels of nitrates in water is one reason Des Moines, IA is either looking at, or is, suing several counties upstream for the excess amounts of nitrates in the Raccoon River.

If you sampled the forest floor and did a soil test you would not find a lot of available N in the samples and yet the plants in that forest are not starved for it.

kimmq is kimmsr

The nitrogen is used in the breakdown of the hydrogen-dense "brown" content. There will be very little if any left. As the compost attracts earth worms and other organisms that secrete nitrogen in their wastes, the nitrogen will increase. If you add fresh kitchen wastes into the garden soil between plants, worms will eat the decaying material and release nitrogen. If you add dilute urine to your fresh compost there will be more nitrogen. Add blood meal, as well.

Well, blood meal is just as well sprinkled around the plants. In other words why compost fertilizers - just use them.

Hydrogen-dense? This is a term I have not come across. As a chemist I am genuinely interested in what role hydrogen plays, since we always talk about C and N in this process but not H.

https://askabiologist.asu.edu/recipe-plant-growth

I'm familiar with the carbon and water cycle and the formation of carbohydrates by plants. I find no mention of the term 'hydrogen-dense' on that page. Perhaps you can further elaborate.

Is terminology so relevant that simple chemistry is of little importance? The fact that plant matter is over 90% hydrogen informs most people that the combination of 1/30th of that content of nitrogen breaks down the composition of the essentially hydrogen-based material. Please, open your mental capacity to see the simple things.

"Hydrogen-dense" is the same connotation to plant matter as "Nutrient-dense" is to soil matter plants grow in. Neither term is needed any dictionary explanation for common people to know quite well what they refer to, the relative abundance of these elements in one set of materials compared to another set

Need we labor over simple, easily understood terminology finesse?

Yes, we do if your facts are wrong.

Common people do not know at all what you are referring to, because even compost experts (many of whom are present on this forum and are smarter than little old me) don't talk about 'hydrogen-dense' materials. But I'll try to ignore your superior attitude and stick to the facts.

It is patently impossible for plant matter to be 90% hydrogen. Carbohydrates have a basic formula (CH2O)n, which a little simple math indicates is 2/32 or 6.67% H. Water, if you wish to include that as part of the content and not just consider dry mass, is 2/18 or 11.1% H. So let's start with where the 90% hydrogen is coming from?

Not to pile on but I have never heard or seen any use of the term "hydrogen-dense" in all my dealings with compost, composting or farming. Neither did Google give me any reference to the term. I suppose Dihydrogen Monoxide could be a hydrogen-dense material (bit of a stretch) but in reference to composting it does not break down.

Carbon-dense?

Lloyd -Please - describe to me a short, easy to understand term that indicates one material similar to another but containing more concentration of one element than the other similar material to use that clearly distinguishes the one from the other.

Please.

The carbon is essentially the same in two - however the hydrogen element as a dry weight is more dense in the lower moisture material. Hence my choice of terminology. Essentially the hydrogen content of carbonaceous organic material reacts with the nitrogen. https://en.wikipedia.org/wiki/Soil_organic_matter

Notice this line in the site above . . . "Lignins are complex compounds that form the older parts of wood, and consist also mainly of carbon, oxygen and hydrogen. They are resistant to decomposition."

These tough lignins are the primary elements of dry organic materials. The nitrogen supports enzymes that reacts with these lignins to break them into elemental content of the decomposed material. The nitrogen is quite volatile and dissipates much faster from the decomposing material that other elements, resulting in little nitrogen left after it is both consumed by the enzymes and gased-off.

Hopes this helps some readers here.

OK. I get it. Hydrogen moves through this process. It is one of the inputs in plant material and it is released as decomposition occurs. But I think that the collective response is... so? Hydrogen is everywhere. We are swimming in it. Air is "hydrogen-dense". There is no need to preserve it or provide it to plants. Unless I am missing something?

Oddly, the pseudo "science" behind the silly, unscientific, proven wrong-headed and actually caught red handed falsifying facts about CO2 "polution" is also a factor in the "It's abundant all around" fable.

No, it is not "Abundant" in any way. In fact, earth is at a very low, biologically-unsustainable CO2 atmosphere level, so if man is capable of pushing this vital nutrient even lower, our plants will vanish, oceans will tun to cesspools with dead plankton and other microbial plants and, well, we will die by the billions, along with all other plant-dependent life forms.

The key is Balance. The hydrogen in woody material is what makes it "woody." it is "dense" relative to non woody plant material. If that is some form of insignificant factor to you, may I suggest that this discussion about the natural life cycle of nutrients in our biosphere is out of your interest and care range?

In fact, these elements are all vital in "Balance" to each other, and the "dense" part is a relative term, as my inclusion of it clearly states.

Thanks for your sharing, all of you. I have no further interest in this messed up delusion about composting. Bye.

Crmstrong, what you are saying makes sense if you substitute "Carbon" for where you are saying "Hydrogen". Could you be mixing up the two?

Bye.

Don't let the door hit ya where the good lord split ya.

!!?!

The good news is, the orbit is so eccentric on that one we probably won't see it again for 76 years. So we got that going for us.

I'm going to go exhale really hard for a few minutes and do my part to fix those unsustainable CO2 levels.

Can't stop shaking my head and chuckling about this thread. :-P