Compost Making FAQ - Part 2
DF>Problem: I have a "by the book" compost heap that is not
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.
* May 8th - I'm writing a book. I've got the page numbers
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?
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
* 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
* May 24th - Pay no attention to the man behind the curtain.