I don't think I'd consider potworms a sign of a healthy worm bin - they are a normal part of the decomposer community, but they do best in conditions that are wetter and more acidic than is ideal for worms, and they eat in competition with worms, like the tiny organic particles and molds that worms also eat

so with the potworms as an indicator that the compost you're using as bedding is too wet and also acidic [well made, freshly finished hot compost should be very nearly neutral pH], and with the heat indicating the compost is actually not finished at all, there is no need to add any "food" to the bin, which is actually fairly small, unless it's a couple feet deep

I have a worm bin currently that's about 32 sq ft, that gets filled from early summer to mid winter to a depth of about 3-4' with really finished hot compost, no additional "raw" food added, and I harvest that material in the spring to use in my greenhouse and garden - no heating occurs, no smells result, the worms thrive with no attention

so if you want to compost your household waste via worm, use a large amount of wet shredded paper as bedding [which they'll happily eat if it stays wet enough to get microbially active], with a bit of finished hot compost as microbial "starter", and feed them with the kitchen waste - if all the household waste you have to process is one filter of grounds a day, you won't support many worms, as they can eat half their weight a day, but coffee grounds don't interest them much - worms don't "refine" anything, the C:N ratio of the vermicompost will be about the same as that of the initial hot compost, if it's actually finished - lab tests of my food waste compost showed 3 batches of hot compost from about 16:1 to 18:1, with the worm compost being 16:1, and I aim for enough coarse carbon [sawdust] to 'capture' that N

the "finishing" that I use the worms for has to do with the texture and homogeneity of the finished product - paper has a C:N ratio of about 4-600:1 - coffee grounds at best are about 20:1 - wet kitchen waste generally is 10-15:1

Bill

Here is a link that might be useful: hot and worm compost bins

I don't think the bed's acidic, Bill. If it were then there shouldn't be excess ammonia coming off. In this area I'm in my element, because when I'm not worming I'm a chemist (and a technical writer). In an acidic environment the basic ammmonia would react almost immediately and would be bound up as ammonium salts of some sort.

But, there could be things that I wot not of. Coffee grounds are a bit acidic, and they could affect the pH of the bed. I think I can test it just in case. I have some dolomitic lime that I use for the garden. A handful of that should clear up any acidity and solve the problem. If the bed's already basic then it'll get a bit worse.

As for pot worms, I'm certainly no expert. But I gather that Kelly (who seems to be one of the senior wormers around here) thinks that they're a good sign. And Mary Appelhof says of them "let them be." She generally regards them as an asset.

On coffee grounds I have only anecdotal evidence, but several experienced wormers here in the bay area use it as their primary feedstock.

I'm pretty certain that the heat in the worm bin is the result of added food, for this reason: The compost that I store in a regular rubbermaid bin (from the same batch as my worm bedding) is not heating up. Only the compost in the worm bin, fortified with extra food, is above room temperature.

The link is very interesting. I'm glad to see that you and others are having good luck with compost as bedding.

I'm guessing at this point that the problem is excess nitrogen in the food decomposing in the bin faster than the worms can eat it. If I can find a suitable carbon source I'll give that a try to take up the excess nitrogen. Perhaps small amounts of sawdust will work. Or possibly bulk coir.

Worse come to worst, I'll set up another bin with regular coir/paper bedding and use that for processing food, while I use the other bin for processing compost alone.

BTW, Bill, about the nitrogen value of coffee grounds...

You've mentioned several times that coffee grounds contain only 1.5% nitrogen. And that's more or less true, as far as it goes. But that number doesn't tell the whole story. According to Elizabeth Stell in "Secrets To Great Soil," the NPK values of coffee grounds are 2 - 0.3 - 0.3, respectively. That is, N is about 2% by weight. Looks small, but compost is 1-1-1. Alfalfa hay is 2.5 - 0.5 - 2. Alfalfa meal (one of the best organic nitrogen sources aside from blood meal) is only 3-1-2 (3% nitrogen vs coffee grounds at 2% nitrogen).

It's not too surprising that coffee grounds just left lying around don't decay all that fast. Alfalfa meal is pretty stable too, left to its own devices. But add either one to a compost pile and it'll heat up fast.

I would take the temperature inside that bin. If it is heating up or spiking, it could kill your worms and that would have the smell of ammonia.

psuliin - Starbucks analysis of coffee grounds doesn't support that NPK, although that's not to say grounds aren't useful, just not the 'magic stuf' most folks seem to think - in addition, if alfalfa meal [lower N then a lot of 'organic' sources, including cottonseed meal and all manures] were put in a bucket as wet as fresh spent coffee grounds, it would most certainly heat up, just like fresh grass clippings ... 1-2% N is not a "high N source", about 20:1 at best, while fresh grass clippings can be 4%, with a C:N of about 6-8:1 - remember grounds, roasted and dried, are high C too

also, you might find general yard waste compost [with a liberal amount of leaves in the mix] that comes out to be 1-1-1, but more likely with a good mix of material it will be 2-2-2, or 2-higher-higher ... the "party line" of 1-1-1 is a real sweeping generalization, my tested composts have always had N ratings above 2, and some had lower P, most had much higher K, as much as 8 - "typical" in my case could be 3-2-6, more like "fertilizer", but also largely food waste, with very high levels of all trace elements, especially boron, high in many of the foods we eat

I think you'll find that acidic compost can easily be gassing ammonia - nearly all compost mixes start off at least slightly acidic, which the microbes prefer, and any compost with an excess of N [meaning lack of C], and lack of air, will offgas, whereas with the proper balance [about 30:1] and good moisture level, with unlimited air flow, it will sequester the N with the carbon

coffee grounds are effectively neutral pH by the time the coffee's gone, and lime is very antagonistic to worms, who actually also prefer slightly acidic conditions - lay a couple out on the ground and sprinkle a bit on them and you should confirm that - but potworms thrive in much more acidic conditions [and wetter than worms need], and while their presence doesn't mean there's anything "wrong" with your compost, they will compete with the worms, they do occupy the same "niche" in the decomposer community, and their presence would indicate to me that the worms have less than ideal circumstances

I'd say if your regular compost doesn't heat up, but does later when you add that minor amount of coffee grounds, then you originally had a lack of N, and the really unfinished compost is "kicking off", tho I'd be real suprised to see that happen from coffee alone

I fed large amounts of coffee grounds mixed with carrot pulp from a juice bar to my worm bin for a couple months some time back, and there was never any heating, nor was there any ammonia gassing - what I did find was the worms processed the mix much more rapidly than they did grounds alone .... and I was never convinced they did much to the grounds alone as grounds are very much the texture and appearance of worm castings anyway :) they might get at them eventually, when nothing more attractive is left

Bill

Bill, I guess we just see things differently. In practical terms, though, I seem to have been right. I added lime, and it had no appreciable effect (either on the worms or the smell). A pH test kit indicates that the compost is somewhere between pH 7 and pH 6.5 - very slightly acidic if at all. Finally, I determined that the reason adding paper didn't help was because it wasn't available enough. Shredding it fine and mixing it well with the bedding seems to have solved the problem.

In other words, it was just a basic compost problem: too much nitrogen for the available carbon, due to the coffee grounds I've been adding.

Now, about your specific points....

1)I don't see Starbucks' analysis as out of line with the published NPK. 1.45% is not much different from 2%, especially since the latter is only one significant figure. My point was that things that are well-known to have a heating effect on compost piles (such as alfala hay) are about the same as coffee grounds in terms of nitrogen level, and that point still stands.

By the way, I don't know if you noticed, but the Starbuck's page also says this: "Combined with browns such as leaves and straw, coffee grounds generate heat and will speed up the composting process."

2) I'm not sure why you think a difference of 1-1-1 and 2-2-2 is all that important for this discussion. What makes compost heat up is a proper balance of carbon and nitrogen, and carbon isn't included in NPK figures. If you adjust the C/N ratio in a compost heap to something around 25-30, and if the components are finely divided, it will get hot. If the C/N ratio is much lower than 25, you'll get ammonia offgassing. That's just basic compost theory.

3)I'm afraid that I won't believe that a strongly acidic pile can produce ammonia until I see it happen with my own eyes. As I said, I am a chemist, and I'm fairly well up on acid-base chemistry. Ammonia is highly basic and dissolves extremely well in water. In an acid pile the ph of the water will also be acid. Ammonia dissolves there and reacts to form odorless salts such as ammonium sulfate. If you take household ammonia and add vinegar to it, eventually you won't be able to smell either ammonia or vinegar, because they will have reacted to form odorless ammonium acetate.
You can try it for yourself if you don't believe me.

4) Every resource I have read lists coffee grounds as acidic, but not as acidic as something like pine needles. As for lime, I think Mary Appelhof's book is pretty much the bible of worming, and she recommends it, as do several other sources I know. You may be confusing garden lime with slaked lime, which IS toxic to worms (and to just about everything else). Slaked lime is Calcium Hydroxide - a relative of lye, and extremely alkaline. Garden lime is Calcium Carbonate - also known as limestone, and the major component of eggshells. I think we can agree that neither limestone nor eggshells are toxic to worms. Dolomitic lime (which is what I use) is just garden lime with a little magnesium carbonate added. And, as I said, the worms didn't have any problem with what I added to their bedding.

5) I agree with you that the reason my compost is heating up in the worm bin is because I probably had a bit too much carbon in the hot bin when I made it, so there's still excess carbon in the finished stuff. So when I add the coffee grounds decomposition starts again and the worm bin gets warm. But I'm quite certain it is the coffee, because that's the only difference between the stuff I'm storing and the stuff in my worm bin.

6) I will consider the carrot pulp suggestion to help them get through it faster. However I'll be even more careful to watch my C/N balance, since that seems to be what's actually causing the ammonia smell. When I add usable carbon to the bin, it goes away.

I think you're right about seeing things differently
re your #1
"You've mentioned several times that coffee grounds contain only 1.5% nitrogen. And that's more or less true, as far as it goes. But that number doesn't tell the whole story. According to Elizabeth Stell in "Secrets To Great Soil," the NPK values of coffee grounds are 2 - 0.3 - 0.3, respectively. That is, N is about 2% by weight. Looks small, but compost is 1-1-1. Alfalfa hay is 2.5 - 0.5 - 2. Alfalfa meal (one of the best organic nitrogen sources aside from blood meal) is only 3-1-2 (3% nitrogen vs coffee grounds at 2% nitrogen)"
Starbucks analysis: 1.45-0-.008 [roughly]

I have no idea where Stells' analysis comes from, I have seen that amount cited only on Primal Seeds website, who also don't indicate where the analysis was done -
as Starbucks says, N is more likely to be closer to 1.5%, maybe slightly over half that of alfalfa or mixed veg waste, meaning grounds aren't a high N scource - 1/2 point may see a trivial difference, but the "whole story" isn't what other nutrients are present, but how much carbon is - high N sources have a C:N ratio well below the 20:1 grounds have, which may be a good ratio for composting if the other necessary factors are present, an even moisture level and good air infusion - if alfalfa meal [closer to 15:1] dried out and repeled water as well as grounds do, it wouldn't heat up in isolation either, but as wet material it definitely would, with no carbon addition, and if wet enough, the N loss would be in leachate more than ammonia gas

I understand basic composting theory well, on a very practical level, as I've made many tons of it, pimarily of food waste with C:N ratios closer to 12:1 .... I know that the addition of the proper amount and type of carbon is necessary to prevent loss of N via either offgassing or leaching, and lab analysis of my finished compost shows I've achieved the sequestering of that N in finished compost that will no longer heat, even tho' the 16:1 C:N is below what is the "proper" ratio for heating

although carbon is necessary for hot composting to be maintained for a long enough period to complete the decomposition process, it is NOT carbon that causes the heating in a compost bin, but nitrogen - N is the 'protein' that allows microbial action [reproduction & healthy growth] to happen, carbon is the carbohydrate that allows the microbes to work and digest - if you use "too much" carbon in composting, there will be no, or less heating, and the decomposition will be less bacterial, more fungal, and take longer

in commercial composting, like with biosolids, the carbon addition is called "bulking agent", for a good reason: it's a coarse material [usually wood chips, I use coarse sawdust] that insures the necessary air infiltration and prevents both excessive moisture or drying - at the same time, it captures the N which might otherwise be lost in a wet pile, through leaching

as for lime and acidity, as I said, lay a few worms on the ground and sprinkle some lime on them and watch'em squirm - not quick lime, dolomite lime .... and not eggshells, which are an excellent source of very slow acting calcium, and if ground finely, also a good source of grit for worms .... worms are largely water, the lime will immediately dry their surface enough to suffocate them - same for wood ash, probably worse because even faster acting

if you looked at my whole page I linked above, you saw a {{gwi:1332764}} of fat healthy worms that had been filled with finished compost [C:N about 16:1] and then had layers of mixed grounds [about 20:1] and carrot pulp (probably also about 20:1] added, covered with wheat grass mats ..... no heating, no offgassing

"I agree with you that the reason my compost is heating up in the worm bin is because I probably had a bit too much carbon in the hot bin when I made it, so there's still excess carbon in the finished stuff."
but then: "When I add usable carbon to the bin, it goes away."
as I said above, an excess of carbon will prevent heating, so if your hot compost actually got hot and maintained that temp for awhile, it's a lack of carbon that resulted in the offgassing, as you indicate by you last sentence .... and I've never said that a pile that's strongly acidic would offgas, in fact I'd expect it would be so wet [and high N] that it would lose the N via leaching .... you should be aware of the logarithmic nature of the pH scale, and the fact that even 6 is slightly acidic .... below 5 your worms wouldn't thrive, but a hot compost pile could easily be as low as 5, without offgassing [sometimes mine are heavy on citrus] .... and adding dolomite to the worm bin could bring the pH up well above 7, which also wouldn't be best for worms - should never be necessary or desireable to add lime to worm bedding unless you've done a proper pH test, although if you've got potworms in it, it's definitely more acidic than needed for worms

try a pH test on the grounds - I don't think you'll find them below 6.5, which could hardly be called "acidic"

sorry, don't mean to be writing a book here :)
Bill

Bill, here are the "bottom lines" as I see them.

No matter what nitrogen level you happen to think coffee grounds have, the fact is that every resource on the subject that mentions them (including the Starbuck's site which you seem to have confidence in) describes the heating effect they have on compost piles. The "bucket of grounds" that you've mentioned many times would be expected to heat up, because they don't have a good carbon source. But grounds added to compost heaps can and do.

Your own sources agree with this, and I've observed this effect myself in my hot bin. In fact, a big load of coffee grounds is my favorite way of getting it hot.

I observed heating in my worm bin, but not in the storage bin for the same batch of compost. The only difference was the addition of coffee grounds to the worm bin. This is consistent with all available information and, moreover, is a straightforward empirical observation.

As heating and decomposition proceed, the C/N ratio of the worm bedding becomes lower. Eventually as more nitrogen is added, we expect that the C/N ratio will go so low that excess nitrogen will be released as ammonia. And in point of fact I am getting ammonia offgassing.

Acidity is not a viable explanation for this, because acid bedding should reduce ammonia release, not cause it, based on simple acid-base chemistry as I've explained. Moreover, pH testing on the bedding indicates that it is no more acidic than common tap water. And finally addition of carbon to the bedding solves the problem, as would be expected if it was caused by a low C/N ratio. So your theory that acid bedding was the cause is not supported by either theory or observation.

Garden lime, limestone, and eggshells are the same thing: calcium carbonate. This is just a simple fact. See here if you don't believe me:

"About 95% of the dry eggshell is calcium carbonate weighing 5.5 grams."
http://www.afn.org/~poultry/flkman4.htm

"Calcium carbonate is now the most widely available and preferred liming material. It is sold under various names such as carbonate of lime, garden lime, ground limestone or ground chalk."
http://www.rhs.org.uk/advice/profiles1104/limingsoils.asp

"Limestone is a sedimentary rock composed largely of the mineral calcite (calcium carbonate: CaCO3)."
http://en.wikipedia.org/wiki/Limestone

They're the *same thing*. If you're comfortable adding eggshells to the bedding, then you should be comfortable adding either of the other two. And as we'd expect given these facts, every authority on the subject from Appelhof on down recommends garden lime for controlling acidity in worm bedding. You don't have to if you don't want to, but your belief that it will kill the worms isn't supported by either theory or practice - as I can tell you, since I added lime to my bedding and the worms are just fine.

There's just no reason for your belief that potworms are a sign of acid bedding. Not only is this not mentioned anywhere I can find except your writings, but I have potworms, and my bedding is not acidic, as verified by testing.

Sorry, but those are the facts. And they just don't line up with your beliefs. I found a solution to my problem based on these facts, so until more actual facts emerge, that's where I'm leaving it.

I think the odor might be from too much moisture. When my bin gets really wet and I dig down in the bottom, where it's the wettest, I smell that odor.

Deanna

well, Deanna understands some :)

"As heating and decomposition proceed, the C/N ratio of the worm bedding becomes lower"
not so, the C:N ratio doesn't change all that much, and it will be the N that's lost first

"So your theory that acid bedding was the cause..."
nowhere have I said acidity is the cause of offgassing, although hi-N, hi-moisture, low-oxygen situations will usually also be more acidic

"limestone, and eggshells are the same thing"
but they have somewhat different periods of action - lime takes a good period of time to affect the pH of a volume of soil or compost, eggshell, even very finely ground, takes even longer - the reason dolomite lime is used in the garden rather than slaked lime is exactly for that reason

I add small amount of eggshell to a worm bin because it provides grit for the worms, I never add any form of elemental calcium to compost, which shouldn't need it, but I do add lime to my garden soil .... when it needs it because of the pH ..... I thought your worm bin wasn't acidic enough to require lime .... and you appear to not have tried the experiment I suggested of applying that lime directly to exposed worms

"There's just no reason for your belief that potworms are a sign of acid bedding. Not only is this not mentioned anywhere I can find ...."
try these links:
"Potworms are often encountered in compost bins and worm farms, particularly if these are slightly acidic. Potworms have a thin cuticle, on the body surface, through which water can diffuse in and out. Because of this, they require 100% humidity and will dehydrate and die in dry environments." [worms are quite the same, but do best at slightly lower humidities]

"....usually found when the bedding in the bin is slightly acidic...."

"Pot worms like acidic conditions. That condition can happen when the bin gets too wet. I don't think the pot worms themselves would hurt your worms..but those conditions, making them thrive, might be detrimental to your worm population."

there's lots more, but repitition doesn't seem to get thru, so I too will leave it with this:

any ammonia smells in your worm bin are caused by unfinished hot compost, with an excess of N [this in fact you've proved by adding carbon], being aerated so that it can re-heat by moving to the worm bin, but being too wet [probably why it quit heating originally], the bacterial composition quickly changes and it becomes anaerobic and offgasses [which you've fixed by mixing in the carbon] .... the slightly higher acidity caused by those original conditions along with the presence of incompletely decomposed wet material on the surface create conditions conducive to potworms .... those conditions may not be enough to be really detrimental to the redworms, but the potworms are competing with them for "resources", and the redworms would do better with conditions that don't suit potworms .... if grounds did anything in the mix, it was due to their structure and drying effect

Bill

"I add small amount of eggshell to a worm bin because it provides grit for the worms, I never add any form of elemental calcium to compost, which shouldn't need it..."

Uh, no, it certainly shouldn't. ELEMENTAL Calcium is a metal that reacts explosively with water to produce highly alkaline calcium hydroxide. You're wise to keep it out of your compost.

However, if you add eggshells, then you are adding calcium carbonate, just like you would be if you added garden lime in the same amount.

"I thought your worm bin wasn't acidic enough to require lime..."

It wasn't. However you were convinced that the presence of potworms meant that the bedding had turned acid, so I gave your theory a fair trial: I tested the pH of the bedding and added lime to see if it would solve the problem. You turned out to be mistaken in both tests: the bedding wasn't acidic to speak of (no more than expected from absorbing CO2 from the atmosphere), and the lime had no effect one way or another.

And yes, I checked your sites. They say that potworms PREFER acid conditions, but that they can do fine without them. Ergo, the presence of potworms is NOT an indicator of acidity, and that is also verified by testing the pH.

"and you appear to not have tried the experiment I suggested of applying that lime directly to exposed worms"

Quite true. I wouldn't apply lemon juice directly to the worms either, but I have no problem adding a small amount of citrus waste to my bin. Likewise lime. And contrary to your warnings, the lime I added still hasn't caused my worms any difficulty.

The rest of your post doesn't contain anything new, I'm afraid. You have a number of theories, but they don't match what I observe. However I've found a solution that does work, and I've posted a thread discussing it for people who want to use coffee in their bins. I can't think of anything else that needs to be said here.

sorry, forgot I was talking to a chemist - for a gardener, calcium as a pH adjuster comes in a variety of forms, each acting at different rates and in different ways ... hydrated lime is relatively fast acting and requires much less to be applied, dolomite is fairly slow acting [even powdered, more so the coarser it is, like granulated or pelletized], eggshell is even slower - eggshell applied directly to a worm will cause little effect, lemon juice only slightly more, dolomite would irritate them immediately and dehydrate them quickly, hydrated lime would kill them - you may have the chemistry down, but you're not understanding it in gardening terms - when when a gardener says "slightly" acidic, or even just acidic, they mean a pH below about 6.8, not below 5 - the preference for eggshell in gardening is the slow acting, very long lasting nature of it

the reason worms avoid fresh citrus products is the limonene in them, not the acidity per se, and quantity added to a worm bin doesn't matter, they just won't be processed until bacterial action deals with the limonene

please note that the reference links to potworms were in response to your statement "Not only is this not mentioned anywhere I can find except your writings...." ..... I was pointing out it's mentioned anywhere potworms are discussed, along with the fact that they only do well in wet conditions .... and yes, as I said, aeration by the thorough mixing in of carbon will reduce the offgassing of excess N by adding air and reducing moisture

Bill

"the reason worms avoid fresh citrus products is the limonene in them, not the acidity per se, and quantity added to a worm bin doesn't matter, they just won't be processed until bacterial action deals with the limonene"

Yes, I know. I used that analogy because citrus also contains something that would be highly irritating if applied directly to worms: the acidic (~pH 3) juice. However when it's distributed throughout the bedding it gives them no trouble. Likewise lime.

Look, Bill, you told me that adding lime to my worm bin would cause my worms problems. It hasn't. I didn't expect it would, since worms get along fine in soil that has limestone rocks in it, and garden lime is literally just crushed limestone. But all theories aside, the bottom line is that the lime gave them no trouble, the coffee grounds are in fact heating the bin (and my hot pile) for reasons that I explained in several posts, and the added carbon in the worm bin solved the ammonia problem.

Thanks for your advice, but it seems to me that's all there is to it.

"Uh, no, it certainly shouldn't. ELEMENTAL Calcium is a metal that reacts explosively with water to produce highly alkaline calcium hydroxide. You're wise to keep it out of your compost."

You might be a chemist but your reading comprehension is somewhere between a monkey's and a 1st grader's. In the context of this debate I think everyone, excluding you, knew what was meant by elemental calcium. Your post quibbling over phrasing shows someone less concerned with sharing information and more concerned with trying to bolster their own failing argument with the intellectual equivalent of crotch grabbing and rude hand gestures. If you can't win a debate based on merit please don't inflict this sort of nitpicking stupidity on the board. Save it for Jerry Springer.