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Making Compost FAQ (long)
The following is a collection of composting advice from Jim
McNelly, aka Mr. Compost. Long-time readers of rec. gardens
will know him well. It is a compilation of some of his replies
to various questions from this group. It contains the
essentials of composting. If anyone has other of his posts
saved, I would sure like to recieve them.
Michael Matthews in central VA
***************************
Newsgroups: rec.gardens
Subject: Composting 101
From: jim.mcnelly@granite.mn.org (Jim Mcnelly)
Message-ID: <36.2009.2817.0N42A21F@granite.mn.org>
Date: Thu, 19 May 94 02:51:00 +0600
Organization: Granite City Connection St. Cloud MN 612-654-8372
As requested, here is my recipe for home composting.
Mulching (leaving things in layers) is easier than "piling"
organic residues, but there is a place for passive compost
piles as well. But for those who desire to make an active,
hot, compost pile that is ready for curing in three to four
weeks, here is my tried and true formula for cooking hot
compost.
Active composting is a BATCH process. It differs from passive
piles that just sit there or continuous flow systems where
stuff is periodically dumped on top of the material already in
the bin.
1. PREPARE THE AREA: Avoid walls and fences that can rot and
discolor. Stay within reach of the hose. Choose a spot away
>from drainage swales and roof overflow. Avoid low spots where
water can stand or pond. Leave plenty of room to access with
pitch fork and wheel barrow. The area should be from 6'x6' up
to 12'x9'.
2. CHOOSE YOUR BIN. Small yards use enclosed plastic,
preferably insulated bins. Large yards use larger open air
designs without covers. Large doors are better than small ones.
Three stage systems are best, but only one, maybe two bins are
active at any given time. The three stages are stockpiling,
active composting, and curing. Curing piles do not need bins.
3. STOCKPILING: Since active composting is a batch process, it
requires a full bin of material and this usually requires
stockpiling. Materials easy to store include leaves, wood
mulch, pine needles and cones, old compost, and shredded paper.
4. INOCULATING: Active composting is helped by adding old
compost or leaf mould as an inoculant. This can range from 10%
up to 50% from the curing pile or the still-cooking, last
batch. Avoid soil except as a last resort. Use bagged compost
or manure if starting for the first time. Packaged inoculants
do no harm, and may even help, but are not a substitute for old
compost.
5.MIXING and 6. WATERING: Layer your various ingredients
OUTSIDE THE BIN, watering each layer as you go. Think "Green
and Brown". Add 10% bulky matter like wood chips to keep the
pile loose to avoid matting. THEN fork the layers into the bin,
mixing as you go, blending wet with dry, watering as necessary.
Water like a seed bed, avoiding runoff. The mix should end up
50% moisture like a damp sponge. Now and during the 3 weeks of
active composting is the time to add table scraps. Avoid adding
lime, it can disturb the natural pH shift and delay
decomposition.
7. AERATE: Like any other form of livestock, your "herd" of
bacteria needs food, air, and water. You have added food with a
balance of carbon and nitrogen, which is the green and brown.
You just added water. Now the bacteria need air. Old compost
theory suggests that you "turn the pile for aeration; recent
studies show that a pile uses up its oxygen in as little as 1/2
hour after turning.
Like a barbecue or a fireplace grate, a pile needs ventilation.
This is provided through a passive aeration base. Some use
brush, stalks, screen on boards, rocks, wood chips, flat
aeration pipe, other mechanism to let air infiltrate at the
base from outside. The air will rise up due to the convection,
chimney effect, of warm air rising. With wood chips added, the
pile will self aerate with an aeration grate without turning.
Poking the pile from the top down to the base with a piece of
rebar or 1/4" rod every 6" will break up mats and provide extra
air channels.
The pile will begin active composting within 48 hours and cook
by itself. You can help the process by mixing at least once
after a week, sort of like stirring the coals, adding moisture
as necessary. When it is not frozen outside, I make a compost
batch every 2 weeks, often using half cooked compost from two
weeks previously to mix with the fresh grass clippings.
Personally, I bag my grass because I like making and using
compost, but letting the clippings lie is a fine way to avoid
the effort of active composting.
Follow these steps toward batch composting and you will see the
pile heat and cook, giving off the steam of life as it
decomposes. I think everyone should experience the pleasure of
having a compost pile cook well at least *once* in their lives.
Two last tips, *underwatering* is the largest single cause of
slow composting. Piles in *standing* water is the number one
cause of odors.
Have fun!
Mr Compost~~~
Jim~ McNelly
Granite Connection 612-259-0801
jim.mcnelly@granite.mn.org
---
* May 19th - What's all this fuss about endangered feces?
DF>Problem: I have a "by the book" compost heap that is not
generating heat.
Sounds like you should compost that book Dave. (g)
DF>Contents: Lawn clippings, kitchen scraps, wood chips from my
shop(possible problem since they contain redwood, aromatic
cedar, and fiberboard, which contains formaldehyde) and plant
food (Miracle Grow).
You need some old compost as an inoculant first off. Secondly,
tell us what proportions of each. My guess is that you are
heavy in the wood chips, of which I do not recommend more than
10% unless composting heavy muck like sewage sludge or wet
chicken manure. Why did you add the chemical fertilizer and
how much? Don't worry about the compounds in the wood products.
DF>I keep it wet and cover it with black plastic. The frame is
a box (3` x 3`) made by stacking cinder blocks. It is in the
north side of the house. I turn it daily with a fork.
Turning daily is never recommended. After the initial mix, I
don't turn my piles at home at all. In commercial operations,
I turn maybe three times in three weeks, twice in the first ten
days. Turning lets out the heat. I assume that the two
dimensions also mean that the box is 3' deep too, for a total
of one cubic yard. Wood chips add structure, but little
available carbon since it is still locked up in the wood fiber.
Adding wood chips to a compost pile is like giving a thirsty
child an eight pound block of ice.
Why did you cover it with black plastic? That is like throwing
a wet cloth on a fire, halting ventilation. Covering a pile
also keeps moisture from coming in. I recommend plastic sides
to keep too much air from coming in from the sides where it
dries the pile and cools it. Air should come in from the base,
like a kettle barbecue or a fireplace grate. It should then
rise out the top, with the chimney effect. Keeping the pile
covered halts the natural ventilation.
DF>Each time I add the lawn clippings it heats up a bit, but it
is short lived.
Yep. The pile is suffocating, and probably lacking nitrogen
>from more green stuff.
Mr. Compost~~~
---
* May 8th - I'm writing a book. I've got the page numbers
done.
Subject: Is this a compost pile? #
Papa Pilgrim writes:
JK>Or What? I have a pit in the far corner of my backyard.
(great stories deleted) All in all, what I am doing seems to
be right and is certainly too much fun. But--is it compost or
just rotted stuff?
Yo bro!
Your pile is a decomposing pile of rotting stuff, not a true
composting pile. True compost is made in batches where the
organic matter heats up, feeds abundant organisms that like the
hot environment, then they cool down.
But most people call any old dark organic stuff "compost". I
saw a commercial for the Troy Built chipper that claimed that a
man can put brush in one end and "compost" comes out the
other! Many of my clients in my composting consulting business
bought large tub grinders thinking that they "made compost".
When they start through the learning curve about making piles,
adding moisture, keeping it turned, they gradually come to
appreciate true compost.
But many people get upset when I tell them that they do not
have true compost, so I maybe have to think of a new word that
means *only* organic matter made from hot, active piles.
But there is no *better or worse* as far as the plants are
concerned. Nature does not make piles, she makes thin layers.
God does not teach bears and other animals to use pitch forks,
carry water, and turn piles. Nature is simple, doing her thing
in layers, a bit each year. The worms do the dirty work.
Humans seem to *need* to make piles. Once we do, we start
composting. When we are done, we put nature's life back to the
soil in layers.
I say do what works for you. Let it grow. We all should be
fruitful!
Mr Compost~~~
* May 23rd - Let me see.... Now how does that twit filter work?
Subject: Sawdust in compost
Michael asks an excellent question:
M>What advice can anyone give in using sawdust (oak and birch
>primarily) in composting. Can sawdust be the "brown" and grass
>the "green" effectively or do I still need to add larger wood
>chips for areation purposes?
The distinction between carbon as bulking material for aeration
and carbon as food was largely lost in the early 1970s when many
sludge composting sites failed due to foul odors. Wood chips
are not "available" carbon whereas sawdust is. Sawdust tends to
compact, however, and too much can "smother" a composting pile.
Too little or too much of a good thing can be a problem.
Composting is largely a process of finding a balance of various
ingredients. I read something about "fuzzy logic" where
numerous variables in cooking, brewing, and composting can be
managed via computer programs, something akin to master chefs,
brewmasters, or composting gurus.
I know that it took me many years and trials and errors before
I became confident in what and how much of various materials to
add. A computer program will rarely tell you *why* it is
recommending a particular mix.
Back to your question, sawdust varies as to its age and moisture
content, but adding around 20% by volume is a lot. I add about
10% wood chips, usually older compost "overs" screened out from
previous batches. I add anywhere from 10% to 50% old compost
as an inoculant, less if the compost is mature, more if it is
fresh. Most piles are deficient in Nitrogen, not carbon.
M>Finally, although I do keep sawdust generated from plywood
>separate from that generated from hardwood, is it OK to use
>plywood sawdust in the compost pile?
I wish I could give a pat answer to this question like I can
paper products, where I say use them all you please. But not
all plywoods are made the same, and I have seen some disturbing
levels of formaldehyde which have me a bit wary at the moment
about particle and plywood boards.
There are so many other sawdust products which are not under
question so I suggest that you follow my general rule, which is
"when in doubt, keep it out." These sawdusts may be perfectly
fine, and I would use them in a mixed waste compost, but in my
own garden? Probably not. When I have more conclusive data
like I have on the safety of paper, I will vary my position
accordingly.
Mr Compost~~~
* May 24th - Pay no attention to the man behind the curtain.
Subject: Composting grass
Waldek writes:
WT>Has anyone had a good experience with composting grass
clippings?
>When I put it in my compost pile it turns into a sticky mess
which takes ages to decompose. I wonder if there is something
the grass could be mixed with to help the breakdown process or
should I join my neighbours in the weekly routine of hauling
bags of the stuff to the curb? Help, help, I'm drowning in hay!
I have composted literally hundreds of thousands of tons of
grass clippings, and bag my grass at home too. I believe that
composting clippings and applying compost to the lawn is better
than letting the clippings lie. (although mulching the
clippings is better than landfilling any day!)
My recipe is the same for home and commercial alike. I have
two active batches going and one curing pile. Each week, I
stockpile the clippings in a holding bin. The next week, I add
the current week's clippings with last week's along with some
old compost (10% up to 50%) which is coarse with old wood chips.
These materials are layered OUTSIDE the active bin, watered
layer by layer. THEN they are forked into the active bin,
mixing thoroughly, watering dry areas. My active bin has an
aeration mat at the base allowing air to infiltrate from the
base. Once the bin is full, since I make *batches* of compost,
I "poke" the pile from the top to the base with a steel rod
every six inches to help it breathe.
Two weeks later, I take half of the older pile and put it into
the curing pile with half going into the new batch as the
compost inoculant. Once the material in the curing pile is
dark and crumbly, I screen it and use the oversize material as
a bulking material. Occasionally I add wood chips to help keep
the pile loose. I never turn the pile, but splitting it in
half to make old and new is a kind of turning. The piles are
always sweet smelling.
Have fun!
Mr Compost~~~
---
* May 23rd - Please let me know if you did not receive this.
Don asks,
D>I would have to agree with the low yield from table scraps,
vegetable peelings, coffee/tea wastes.
I must have missed the first part of the post. Are you talking
about low volume (total amount of compost) or the low nitrogen
value of compost in general, or compost from these ingredients?
Let me try to answer all three questions. The volume of
finished compost is typically 1/3 of the original volume, more
if there is free air space in the original mass. Brush shreds
down to about one tenth the original mass, for example. Mass
reduction is another matter. Net dry weight loss is typically
one third. This is actual nitrogen and carbon conversion to
ammonia, heat, and CO2. Most weight loss is from moisture
reduction from 80% moisture original matter such as wet grass
clippings or fresh garden scraps down to 40% moisture compost.
As far as fertilizer values, I have yet to make a true compost
that is over 2% nitrogen. Sure, I can have unstable compost
which is higher, but a cured compost will not be over 2% due to
the inherent biological restraints of the carbon to nitrogen
equation which is essential for proper decomposition. Higher
carbon ratios will result in lower net nitrogen values. Higher
nitrogen in the original feedstock will result in the release
of air borne ammonia and other nitrogen compounds and water
borne nitrates and nitrites.
Compost N values are stable so the can automatically be doubled
when compared to chemical nitrogen values, of which 50% or more
is lost in the first 24 hours of application. Compost N values
also have an accumulated fertility quotient, of which 60% is
available the first year, 20% the second, 10% the third, 5% the
fourth, and so forth. Chemical N has no accumulated value.
As far as the low volume of incoming table scraps as compared
to the net demand of they typical yard, I can state with
certainty that even if you bag and compost all of your yard
trimmings, leaves, and table scraps, your organic matter demand
for the yard is still greater. I recommend 1/4" of compost as
a top dressing PLUS letting the clippings lie in order to keep
a lawn organically sustainable. If you are trying to increase
the lawn's humus content, that requires an additional 1/4 inch
to make the soil richer.
One quarter inch of compost is one cubic yard spread over 1232
square feet. The typical lawn at 3,500 square feet requires
three cubic yards to be sustainable (with letting the clippings
lie) and twice that amount to build the soil up, usually
applied as a top dressing in the spring and fall. If a person
was improving the soil *before* the sod goes in, then 32 cubic
yards spread 3" deep would be called for.
You can see why I believe that it is important to support
municipal composting, as the single homestead is hardly capable
of generating sufficient compost to keep up.
As far as recommending good small composters, I recommend any
of the small, plastic, enclosed bins such as the Earth Machine
or Green Genie. I recommend round ones over square ones as
square bins have cool corners. Table scrap bins should be
covered to inhibit rodents and should not have too many
openings on the side. I do not recommend open air designs for
passive, table scrap bins as they let in too much air, dry out,
and let in vermin.
Pay no attention to the supposed door underneath to take
compost out. They are hard to use and compost does not "flow"
so well. Use instead bins which act like "jello molds" which
can be lifted off when full and the composting process started
new in a different spot. The old pile keeps its shape and will
cure just fine in the open air. Remember to use some old
compost mixed in with the fresh table scraps. This inoculates
it with active bacterial cultures and helps cover it from flies
and vermin.
For the best home composter, I recommend indoor redworm boxes.
Check out Mary Appelhof's book "Worms Eat My Garbage" for tips
for the budding vermiculturist.
Mr Compost~~~
* April 9th - Man, that lightning sounds clo#A#v!&^#v?##vNO
CARRIER
Heather writes:
HB>My husband and I have been composting for over a year in a
bin made from pallets (it is a cube about 3-4 feet on a side).
We want to compost mainly so we don't have to throw away our
vegetable scraps.
For table scraps and vegetables, I recommend smaller enclosed
bins. Large open air bins such as you describe are best suited
for batch, not continuous flow composting. Your type of bin
dries out too quickly, is hard to inoculate with old compost,
has corners that stay cool, and is generally unwieldy for small
amounts of matter.
We generate about a large stock pot worth of vegetable
>scraps a week or maybe a little more. We want to be able to
add the vegetable scraps to the heap without much trouble, but
we have had trouble with a bad smell and flies unless we cover
the vegetables completely with dirt (even leaves didn't work).
Your loading rate exceeds the microbial capability to decompose
the material. You need to begin active composting or throw the
scraps into the landfill. Flies are a sign that something is
wrong. Passive composting for the loading rate (amount of
stinky stuff) you have just doesn't cut it.
This is a lot of
>trouble - either we have to add a lot of dirt or we have to
dig around in the semi-composted mass to try to get the
vegetables all covered up. Surely there is an easier way.
There is no "easy way" to compost putrescible matter. Think of
an "easy way" to bake bread. The easy way is to send the
material to a centralized composting site where they practice
active composting. Then purchase the finished compost from
them. Like you buy bread from a baker.
I have seen a lot of
>information on composting but I haven't found a solution to
our dilemma. I would appreciate any advice.
Check out my previous notes on active composting. It really
isn't all that difficult once you get the hang of it. I don't
turn my piles once they are properly made, mixed, and situated
to self-aerate from the base. I let redworms do the curing.
Mr Compost~~~
* May 22nd - Composters have heaps of fun.
Subject: Mold in Compost
Connie writes:
CC>I have a considerable amount of powdery white mold or mildew
>in my compost pile: not just on the surface, but layered dwon
>quite a ways. Does that mean the pile is too wet, dry,
lacking in something or other?
It is a sign that everything is going well. No worries!
Mr Compost~~~
* May 22nd - Buy high, sell low, or something like that
David C writes regarding using grass clippings:
DC>A more immediate concern is the use of commercial herbicides
on lawns.Many of these herbicides will do extreme damage to
garden plants.I no longer compost or mulch with grass clippings
unless I am confident they are from herbicide-free lawns.
Your concern about uncomposted grass clippings with herbicides
has some merit, although most of the damage that
over-the-counter lawn chemicals can do is past within a few
days after spraying.
But as far as concern about using grass clippings in the
compost pile, your concern has been shown by numerous tests to
be unfounded. The composting process, even a passive pile, is,
in and of itself, a *treatment* for most common herbicides. By
the time the compost is dark and crumbly, the herbicides are
not only not a problem, they are virtually undetectable.
This is not true, however, for agricultural herbicides, some
pesticides, and many commercial chemicals used for spraying
trees, especially fungicides.
But most of these chemicals are not going to be uptaken by
plants, or incorporated into the plant itself. Few organic
certification processes regulate the source of the organic
matter for composting unless there is a clear pathway of
ingestion of chemicals into the food chain.
If you start restricting materials for composting because they
were produced outside of organic methods, your available
feedstocks will become fewer and fewer. I believe that the
benefits of organic matter in the soil far outweigh any real or
presumed biohazard from residential residual biocides in
municipal yard trimmings.
If you want *real* environmental concerns to address, try
arsenic in treated lumber, salts from road de-icing, motor oil
>from crankcases, household batteries in solid waste, lead in
wine bottle wrappers, mercury in electric shoes, runoff of lawn
fertilizers, nitrates in drinking water, rural burn barrels,
on-site dumping, unlined landfills, agricultural nutrient
runoff, incinerator emissions, and 1001 other documented
environmental concerns.
I get tired of people bashing compost and sewage sludges over
perceptual biohazards such as lawn chemicals in grass clippings
and inks in newsprint. It is difficult enough to permit and
operate composting facilities when people we environmentally
concerned composters would think would be our allies, the
organic gardeners, turn out to be some of our biggest opponents.
---
* June 21st - The Universe is over. We can all go home now.
Subject: cold composting
Mike writes: MN>Hi: Being aware of your wisdom from following
your posts to rec.gardens, I imagine you might be able to
provide me with some help regarding info on `cold composting'.
Well, my propaganda proceeds me or my paid supporters need a
raise. But thanks for the kind words anyway. (g)
I saw and pursued a reference to a recent Audubon
>Magazine article on an interesting gentleman who got his
county in an
>uproar by bringing in huge amounts of wood waste to his
land. He carried
>out what was referred to as `cold composting' to speed the
breakdown of
>the woody material (without any shredding or grinding) by
fungal action.
>Besides keeping the material moist, are there other tricks?
My understanding of the story was that the amounts were not
quite so "huge", like great tire stockpiles ready to be hit by
lightning, but were fairly normative mulch layers. The "huge"
terminology might really more aptly be called "out of the
ordinary". Huge, to me, implies thirty foot high stockpiles
such as one might find at a sawmill. Even then, people are
hardly in an uproar over these "huge" piles. The concern it
seems, is the fact that the material is deemed to be "waste"
and therefore subject to the NIMBY or NIMTOF (not in my term of
office) syndromes.
> My personal interest in this is not so grand as this
character's;
>I've just got whole lot of branch wood and prunings that I
am slowly
>making a dent in with a 7 hp Mac chipper/shredder. I mean a
whole lot--
>a pile 40 feet long by 12 feet wide by 5 feet tall. It's
daunting to park
>the chipper next to it and wonder how many hundreds of hours
it will take
>to reduce it all to mulch.
Ah yes Grasshopper, Master Po said to Quai Chang Kane, when this
stockpile of brush is reduced to humus, then it is time for you
to leave.
The first point is that nature does not compost; nature
mulches. We do not see piles of organic matter in nature,
aside from a few notable exceptions of mound building reptiles,
nesting birds, rhinos in dung etc.
Nature deposits organic matter down in thin layers where it is
"cold" composted, if ambient temperatures can be called
"cold". Years ago, it was called "sheet" composting, but one
rarely sees such a term anymore.
But the fact of the matter is that it is the mesophiles,
organisms which function from 40F to 120F that are the true
decomposers. The thermophiles, those operating over 120F up to
the pasteurization temperature of 147F, are lazy sons of guns
who thrive on the heat of their cooler brothers, but do little
to aid the decomposition process themselves.
When a carbon compound is broken biologically, one mole of CO2
and one mole of heat is released. In layers, this heat is
dissipated through convection. In piles, this heat is retained
due to the self-insulating properties of the composting mass.
It seems that the best temperatures for decomposing carbon,
which wood mulch represents, are in the 110F-120F range. Much
of this carbon is bound by cellulose which is highly resistant
to decay. The best means of attacking cellulose, aside from
hiring termites, is to enlist the aid of fungi.
This is what termites actually do in their gut, and is what the
gentleman referenced in the Audubon report is also doing. I
would suggest adding around 10% old compost to the wood mulch to
assist the inoculation process so that the decomposition can
proceed in earnest. Keeping it moist as you note is also
essential.
The real question is whether or not the organic matter is being
processed for a beneficial use or if it is being "disposed on
land". If the person is simply stockpiling in order to garner
"waste tipping fees" with no plan for the ultimate beneficial
use of the mulch or resultant decomposed organic matter, then I
would challenge the plan, just as I would stockpiling tires.
The greater crime is sending organic matter to the landfill
where it serves no beneficial use at all. Even worse, it
decomposes into explosive methane, merges with toxic leachate,
shrinks the landfill causing cracking in the clay cap, and
benefits no soils at all. So even a farmer making an extra
buck spreading wood mulch is better than the landfill
alternative.
Mr Compost~~~
Jim~ McNelly
Granite Connection 612-259-0801
jim.mcnelly@granite.mn.org
---
* June 22nd - The dinosaurs quit while they were ahead.
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Granite City Connection (612) 259-0801
Email: jim.mcnelly@granite.mn.org (Jim Mcnelly)
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