Non Chemical Weed Control

Kenneth Hixson
Sat, 08 Nov 2003 19:04:44 PST
Hi, all:
As a followup to the pre-emergent weed control discussion, some of the 
techniques I have used here might be interesting-more for how I try to 
control weeds than exactly what I do.  Under different conditions other
techniques will be necessary.   I am anything but an organic gardener-
some of the things organic gardeners choose to do seem overly effortful-why 
apply a thousand pounds of organic fertilizer which must be saved,
and spread, when a twenty pound bag of chemicals will do the same thing?  
In the same vein, weed control could be a full time occupation, when a few 
sprays of chemicals will do the same job much faster-and if your time is of 
any value, also cheaper.
	First, control weeds before planting an area-with a hoe, a shovel, 
tilling, or chemical sprays if needed.  After planting, mulch-here, with many 
rhododendrons, bark mulch is used, which is locally produced.  In your area, 
whatever is available and economical.  An organic mulch which adds nutrients 
to the soil seems desireable, but gravel works well in rock gardens.  As
the mulch 
eventually begins to break down, either renew it, or hand weed.  You can
grass, persistant weeds like oxalis, canadian thistles, even blackberries,
if you
get them small enough.  It takes persistance to get them while small.
	When they get a little bigger, use a knife.  I bought a set of steak 
knives, which are kept with the weed control equipment and are never in the
They have a serrated blade, and a plastic handle.  If I leave them out after 
a weeding session, they'll still be there, even next year, unharmed.
A knife makes quick work of small clumps of grass, many broadleaf weeds, even
dandelions.  Using a knife does not disturb the soil the way pulling weeds
	When weeds get too large for a knife, then a spot spray of weedkiller
like Roundup works.  A small hand carried bottle is always available and
carried where needed.  Once you have a hand spray bottle, a gallon of spray
solution can be mixed and available at all times.  When a weed grows in a
of something, a "drip bottle" such as a liquid detergent bottle can be used.
A paintbrush can also work to apply liquid weedkillers.  Anything used with 
chemicals, including weedkillers, should be clearly marked as such.
	When dealing with a large area, and weeds seeding in, there are several
possibilities.  Cultivation is the oldest method, but labor intensive.
	Mulches of various kinds are a good alternative to cultivation in
many situations.  In addition to conserving water and adding nutrients, a
good mulch prevents weed seeds from germinating by blocking sunlight,
the ground from temperature extremes, and may make weeds easy to pull.
	I don't like to use black plastic for several reasons, including
the fact that once applied it is ugly unless covered, blocks water to plants, 
"kills" the soil under them, and eventually degrades and must be removed 
and replaced-meaning yet more "junk" to go to the local landfill.
	There are weed control fabrics which allow water to penetrate, but are
still not pretty, and eventually must go to the landfill.  I also find that
while weeds do not usually grow through them, weed seeds will germinate on
of them and grow roots through the fabric, and are then a problem.  Weeds
also creep over the edges and root down.  In other words, they still must
be weeded,
if less than bare ground.
	At one time, oxalis was a major problem here-anywhere peat moss has been
oxalis is likely to appear.  No chemicals controlled it, pulling it just made
more pieces to sprout.  After several years of effort and the oxalis winning
more ground, I finally found a method that seems to work.  I smother it.
When an oxalis plant appears, a piece of paper is placed over it, then mulched
with something to hold the paper in place.  Here in this rainy climate I
use four thicknesses of newspaper, but have also have used waste paper,
old computer paper.  Mulch not only holds the paper in place, it is a lot more
attractive than newspaper-and believe me, "bright white" computer paper in the
garden stands out from far away.
	I grow many plants in containers, and the same technique works for them
also.  When first trying to smother oxalis in containers, I very carefully cut
newspaper to just fit the container, cut a slit to the midpoint of the circle
so the paper could be slid in around the stem of the plant.  With age and 
increasing laziness, now a square is cut, placed on the container, and the
edges tucked under to resemble neatness.  It works just as well.  If the slit
you cut allows weeds to grow through, put two layers of paper on the pot,
the second two layers 90 degrees so the slits overlap only at the stem of the 
plant.  Occasionally an oxalis plant will grow right against the stem of the
plant being mulched, and can simply be pulled-any root suckers do not seem to
find the same hole.  Plants around the outside of the pot also can be pulled
in the same way.  Once in a while a plant has to be remulched with paper, but
very seldom.  
	To my amazement, this technique even works on bindweed/convolvulus.
Because bindweed suckers widely, it often needs to be remulched, but it can be
killed in one growing season-in contrast to chemical controls which usually
to need three seasons of persistance to control bindweed.  You will have to 
mulch a wider area, and it will possibly sucker through the mulch--simply
another layer of paper, wet it down, and remulch.
 	Canadian thistle can be controlled, but the paper must be held down with a 
heavy object-a full pot, large rock, etc.  It may also work to cut off the
stem with a shovel or knife so it doesn't push the paper up and expose the
thistle to
	Those of us with dry summers can also reduce weeding by using drip irrigation
instead of overhead sprinklers.  There is still some weeding, but in truth, I
rather like to weed--a little.  It gets me out with my plants, and I notice
things I otherwise wouldn't have time to see just walking by.

Ken, western Oregon

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