On 11 May 2003 10:33:14 -0700, )
wrote:

Hi All,

I have a 5,000 square foot area that will be used as neighborhood
playground. The area was full of weeds, which have been manually
removed and has now been covered with a very high quality weed block.
As a long term solution, we were interested in using rubber
mulch, but the cost was too high ($7,000 to $10,000 at a depth of 2.0
inches). As an alternative, what mulch would you say was the longest
lasting / slowest degrading type of mulch (cypress, pine needles, pine
bark, cedar, cocoa pods, coconut shells, or etc...). We are needing
approximately 32 cubic yards and would prefer not to have to perform
as much maintenance. Are there any mulch that do not break down or
that break down into matter that doesn't support weed growth?

Thank you so much for your advice,

Though cedar woodchips break down into nutrients when buried & with
sufficient nitrogen in the soil to help effect the break-down, when used
only as a surface mulch, the largest grade chips don't break down in five
years. If by a "weed block" you mean some kind of garden fabric, that will
can make large grade cedar wood chips last a decade. These chips have a
natural preservative oil that makes the chips last an awfully long time if
not mixed with enough nitrogen & soil to encourage beneficial funguses to
go to work on the wood. If the worst it experiences is rainfall it'll last
indefinitely, just as would unpainted cedar shingles on a house.

The only drawback is the largest grade wood chips can continue to splinter
if it contains chipped wood rather than just the bark, so on a playfield
can give kids splinters who fall or wrastle in it. A finer grade would be
safer to play on without getting splinters but wouldn't last as long as
large chips. Pine bark & wood-shavings does not splinter like cedar &
makes a softer surface to play on, but its natural preservative oils
aren't as radical as for cedar. Although in fact, other woods such as
spruce & spine & aspen, which splinter less than cedar (aspen shavings
don't splinter at all), do also last a very long time when not buried in
high-nitrogen soils & especially when barriered against direct contact
with soil. I don't know off hand if white cypress splinters the way large
bits of cedar wood does, but if it does not, white cypress also contains a
large amount of preservative oil & large chips would last a great many
years. The natural oil in both cedar & cypress keeps them from rotting
into loam unless one takes such measures as buring the chips & adding
nitrogen to start it breaking down, which is why unpainted cedar shingles
never rot away merely from rainfall.

Rubber mulch toxifies the soil with zinc. If any part of the land were
needed for something else at a later date, or even just flowers at the
edge of the playfield, it would be difficult to impossible to remove this
polluting material, & the leached zinc would kill all nearby flowers (some
woody shrubs adapt, but flowers are doomed by this toxic waste that is
being increasingly & harmfully promoted as a mulch). By comparison, if
someone changes their mind after covering the surface with bark, it can at
any time be churned into the soil & some nitrogen mixed with it, at which
time it begins to break down with no toxic after-effects. (The phenols in
pine & cedar can kill weeds & plants if it is laid on thickly, but phenols
eventually break down or evaporate, & are not in the long run harmful in
the environment the way rubber & its zinc content become a permanent
pollutant where rubber mulch is laid down).

-paghat the ratgirl

--
"Of what are you afraid, my child?" inquired the kindly teacher.
"Oh, sir! The flowers, they are wild," replied the timid creature.
-from Peter Newell's "Wild Flowers"
See the Garden of Paghat the Ratgirl: http://www.paghat.com/