Evening star., 1947-12-07

Soil improvement is a constant
problem with Washington garden
ers. They have heard much OF the
value of manure but find it diff
cult and costly commodity to obtain.
Those who are fortunate enough
to have available a steady supply
extol its virtues, but fail to mention
the weed seeds, odors and other
drawbacks. Nevertheless Well-rotted
COW manure is a most valuable soil
improver.
Another material, peat moss, has
demonstrated its value. German
and Swedish peat were popu-
lar and widely used before the war
With those supplies cut off, seVera.
American peats were tried, with
varying degrees of success. The
peats from Maine seem to be most
nearly comparable with the i'm
ported, however, they are much
more costly.
During the war other materials
were tried and many articles were
indorsed in the Horticultural press
but saWduSt was seldom mentioned
Now the Michigan Experiment Sta
ton has tested saWdust and for the
first time we have some definite
facts, yet, with even this help, there
are questions still to be answered
Mulch and Soil Improver.
Research shows that sawdust is
of value both as a mulch and as
a soil improver. 1t does not, how
ever, indicate just which of the
many kinds of sawdust are good
or which should be avoided. A
recent article describing an anna
teurs experience stated that he pre-
ferred mixture of hemlock and
oak. Such a mixture worked well
with vegetables, blueberries and
ANIMALS.
Many gardeners feel that pine
sawdust should be avoided because
of the pitch. OF course, any we'll
rotted.. sawdust is useful but here
we are thinking of fresh sawdust.
Small sized particles seem to
mold and this would be undesirable
The larger particles, you might say
chips. seem to be better suited. This
type usually is most easily obtained
from country saw mills.
Most gardeners begin using saw
dust as a mulch, which later is
spaded into the soil. The research
indicates that a layer of saWdust
around our plants can produce in
furious effects. The bacteria working
on the saWdust must have nitrogen
and, unless it is supplied, they will
rob the soil, which usually means
an adverse effect on the plants.
Nitrogen in Several Forms.
The nitrogen needed may be fur
nished in any one of the several
forms available-ammonium sui
phate, ammonium nitrate, nitrate OF
soda, etc. The three just mentioned
are highly soluble and may be used
in LIQUID form. This will seem to
be a rather expensive way to mulch
the garden-buy the saWdust and
feed the bacteria nitrogen fertili-
zers. However, it is not quite that
bad since the nitrogen is not lost
and will ultimately be used by the
plants.
The method of using sawdust will
vary according to the plants. Azal-
cas- and rhododendrons may be
mulched in the spring with a two
inch layer Of sawdust. The same
applies to blueberries and other
woody acid-soil loving plants. They
will need two or three applications
of nitrogen before the first of Aug
ust.
Sawdust mulches for the peren-
NAL border might we'll begin with
light application in May, half
inch thick, followed by tWo-incE
layer in June after all the plants
have poked their heads through
the ground Nitrogen will need tc
be applied about the same as for the
woody shrubs.
Light Mulch on Seedlings.
In the vegetable garden, and the
annual flower beds. light mulch
may be used as the seedlings ap-
pear. When all are we'll started ad-
ditional sawdust may be spread tt
keep down the weeds and conserve
moisture. A two-inch layer seemi
to be as thick as needed, although
with our hot summer we may wish