Re: Mulching with oak leaves

Well, sounds like your leaves never got damp enough if you found a
foot of matted but unrotted leaves and they didn't rot when you
chopped them up.  Leaves have *got* to be moist or they just sit
there forever and don't rot.  But, when moist and rotted, oak leaves
make superior leaf mold, which is a marvelous addition to beds,
borders and potting soil.

I have numerous huge oaks who dump enormous amounts of leaves every
year.  I either chop and use as mulch, if I have time, or pile them
up and let them rot, along with all the other leaves I rake, blow,
and pick up.  The fresh leaf pile will be almost as tall as I am(
5'4").   In a year, I have highly reduced pile of black gold, maybe
18" tall.  But, as I said, you have got to make sure the pile is
thoroughly damp.  If you pile and compact dry leaves, even a lot of
rain won't really penetrate to moisten them and you'll find clumps in
the pile a year later that are just as dry as the day you put them
there.  If they are damp or you water them in layers as you put them
down, then they don't tend to dry out and normal rains and snow will
keep them moist enough for the lil' microbes to do their thing.  If
you want them to rot faster, adding nice juicy fresh grass clippings
works a treat - pile still has to be damp, tho'.  The grass supplies
the missing nitrogen.

It has been my experience that about any organic material, when
thoroughly rotted, becomes neutral in pH.  I also think that, while
leaves have a lot of good things going for them, rotted they are low
in nitrogen, so you do need to add nitrogen when using them in great
quantity or as part of a potting mix.

I have read, can't remember where, but since it bore out my own
observations, I tended to remember it, that oak leaves do not acidify
soil - the soil is already of an acid nature or the oak trees
wouldn't be growing away happily in it.  I say "acid" advisedly as
that doesn't necessarily mean really acid, as in a pH of lower than
6, but as opposed to a truly alkaline or neutral soil (pH of 7 or
above).

As an aside, I visited the marvelous garden of Jim McClements in
Delaware this spring.  He has been making raised beds of sand and
chopped leaves (many of them oak leaves from his big trees) for some
time now and those beds grow amazing plants.   The beds start out a
couple of feet tall and end up maybe 6" tall after a year or so.  He
layers chopped leaves, sand, manure and peat.  The originator of this
method made the beds in fall and let them sit over winter before
planting, but Jim has planted straight into the freshly made beds on
occasion and had no real problems doing so.

If I can manage to get a load of coarse sand one of these days, I
shall try this.  You cannot believe the size of the plants growing in
these beds; his Arisaema ringens were over 2' tall! (mine have yet to
become much over a foot tall).   And his Asian Podophyllum were
amazing - huge.  He has started making the beds on a groundsheet of
black plastic, to stop tree root invasion.  This holds  moisture in
them as well, which has encouraged several plants that prefer damp
soil to be extraordinarily happy.  Of course, this type of bed will
dry out quickly, so is only really practical if you can water
regularly or have very regular rainfall.

We had an email exchange after my visit about what might be
substituted for the peat.  He has tried assorted things but wasn't as
happy with the results.  I'm thinking pine bark fines would work if
you mix them well with the other ingredients.  He basically layers
and does not mix, so the time he tried the pine bark fines, he found
they tended to clump up, but I think if they were mixed with at least
the manure, they would not.  I use them as part of my potting soil
mix and they work well without clumping.

When I first started gardening here, I used to patrol the
neighborhoods for bagged leaves, dragging my daughter with me to
"help".  Embarrassed her no end, having to drive around with this
crazy lady, nabbing bags of leaves off the curbs:-)   She was so
afraid someone she knew would see us - parents!!!  How embarrassing
they are to the young:-)

Now, I have an endless supply of leaves, it seems and *many* hours
are spent removing them from drives, paths, beds, borders and what
passes for our lawn.  What I really crave is one of those
unaffordably expensive walk-behind leaf vacs that looks like a lawn
mower on steroids, with a hose attachment for getting them out of
planting areas.....sigh.  I find the bag on my electric leaf
blower/vac gets so durn heavy and is so awkward to deal with that I
end up raking or blowing leaves into a pile and then sucking them
into the vac - double work - but the lawn mower doesn't chop them
fine enough to use as mulch.  

Marge Talt, zone 7 Maryland
mtalt@hort.net
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----------
> In a message dated 10/3/2003 1:41:22 PM Eastern Standard Time, 
> justme@prairieinet.net writes:
> 
> > Excuse me Bill, but you are correct for the average backyard. I
did have 
> > some property (summer place) that was literally a forest of oak
trees. When we 
> > aquired it, no one had touched it in years. We took out a few
trees and raked 
> > up years of matted leaves, a good ft and half deep. Had a very
hard time 
> > growing anything till we amended the soil to nuetralize the
effects of all those 
> > oak leaves. On another note, the surrounding 4 acres that were
not going to 
> > be used, we ran the lawnmower thru the leaves thinking it would
help them 
> > decompose. After ten years, they were still there.... killing off
any hopes of 
> > natural vegitation. What I found is, some are great- too many and
you have a 
> > problem.

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