North American Fruit Explorers mailing list at ibiblio

[Alan Haigh <alandhaigh@gmail.com>]

According to Linda Chalker-Scott's interpretation of research, 4" of
arborists chips will stop most weeds.  I'm not sure this is true in the
northeast but I've not carefully kept track with depths and woodchips might
start off 4" thick but rapidly thin with compression and rot.  I place
several sheets of newspaper beneath the mulch to slow weeds myself and this
controls weeds for long enough to limit things to a single annual
application although by about mid-summer the weeds will appear.  By that
time they probably do more good than harm in helping hold onto soil through
winter and they don't suppress tree growth appreciably by that point (
according to research I've seen).

Woven fabric can be affective but it does shed water if not topped with
mulch or placed over concaved soil.  The spun stuff is made to be mulched
over and needs to be lifted and refreshed annually until it's too weak and
torn to use.


Best methods of mulching depend on many factors.  Arborist chips will
enrich the soil which can be beneficial but for fruit trees may get out of
hand after a few years by creating a soil just too rich for highest quality
fruit.  That is just an educated opinion and not research rooted but I've
got some peaches that I mulched for over 15 years and they've become too
vigorous and the peaches less sweet.   Peaches are huge, though.

Shredded wood mulch also repels water once it mats up- usually about a
month after putting down and must be broken up with a fork to counter
this.  If you are just trying to mulch a small area under a tree to make
mowing easier this can be an asset.  No newspaper needed- shredded wood can
stop weeds for a long time.

How much the cooling affect of mulch matters is questionable since most
research shows that mulched trees do grow faster, suggesting the trees are
just fine with the cooler but more moderated temps.  You are only
duplicating the conditions trees produce for themselves in the forest after
all.   Preferred soil temps vary with species and peaches like it warmer
than apples, as I recall.

http://www.puyallup.wsu.edu/~Linda%20Chalker-Scott/Horticultural%20Myths_files/index.html

Here's a collection of articles by Ms Scott that includes her take on wood
chips.