I would appreciate any comments on this plan to
control weeds around my raised beds.
I live in So. California and have raised beds in my
garden. I have waged a constant and losing battle
with crab grass growing in the areas between the
beds. I don't want to use chemicals and get sick
and tired of pulling the damn stuff, it is very
tough and hard to pull.
At one point I covered the entire area with
plywood. That worked well, and looked nice, for a
couple of years until the plywood started to
deteriorate and compost into the ground. The grass
grew right through it.
So here's my plan. I am going to cut the grass down as short as I can
get it, then cover it with heavy duty plastic, like painters' tarpaulin,
and then cover that with about three inches of bark chips.
I am sure this will work in the short run. But,
will it work in the long run? One thinkg I am
concerned about is water collecting on top of the
plastic. So I intend to puncture the plastic in
many places using a pitch fork to allow drainage.
What do you think? Is there something I am not taking into consideration
here? Will this last? Thanks for your attention.
done that, too. eventually the chips become soil and grass will grow
what you want to do is heavy plastic, punctured with something much
smaller than pitchfork (I suggest an ice pick), and covered with 2
inches gravel or slag. Make sure that the plastic goes under the beds
edges. Next best is to go to the city dump and take home some used
carpet. it may be poisonous, but not as poisonous as your back feels
after a weeding session. This is not totally foolproof, some stuff
will push through, but very little.
well, carpet is easy to clean up then, and just as good as plastic.
Put it down upside-down and will both look less ragged and
(surprisingly) less easy for weeds to penetrate. I suppose they get
tangled in the hair if they try to push through. In fact, I can not
remember a single weed in the pieces I put down upside down. Should
have done that will all of them.
carpet is a bitch to cut properly, so I ended up using only the small
pieces and throwing away the big ones and I only covered less than one
path out of four. it was a mistake in retrospect but I also had
concerns about putting too much toxic stuff in the garden. but look, I
have one aisle which is wood chips on plastic, and there the weeds
were three feet high this summer even after I hoed in May. I whacked
them in July, but that's no way to have a garden path. from there,
grass sends runners into the beds, which I have to weed, and plantains
and other weeds lean over the beds with their seedheads, so weedy
paths are a major nuisance. do the job right, say I, no organics of
any sort, and a permanent solution. slag is crushed concrete, cheap
gravel substitute. it is as close to organic as possible, because it
will lime the beds while preventing growth.
That's interesting about the carpet, because I tried carpet once and it
turned into a mess because the crab grass grew right through it and then
the carpet was stuck to the ground by the grass! Yikes. But I put it
smooth side down. I'm going to try the fuzzzy side down just to see if
but I ain't going with the gravel/slag solultion. Just too messy. I'm
going to try some weed block fabric and see.
Thanks and good gardening
Buy some weed mat, it is a plastic that is woven so water flows through. I
used a double layer and it lasted well over 10 years with NO weeds. I too live
in SoCal, Chino, and have used it successfully for your same problem.
Of course a little boiling water has a positive effect on weeds.
The significant problems we face cannot be solved
Since you live in Southern California, the clear plastic method will work
very well for you with all that direct sunshine. Here's how to do it.
Mow the grass/weeds as closely as you can (and rake off all you can). Lay
heavy-weight clear plastic, as heavy as you can get (I use 6-mil). If it
is possible to do so, tuck it under the edges of your bed; otherwise, get
it as tightly against them as you can. Since this is a walkway, you
probably don't need to secure the middle, only the edges. Note, *clear*
plastic, not black, black doesn't work. I always water before laying down
the plastic to make certain the ground is moist for the process.
How it works: Because they have light, all of the seeds sprout. The
plastic holds in the moisture which, under the summer sun, superheats the
soil at the top and kills the seedlings. How far down into the soil the
plants are killed will depend on the heat, light, moisture and soil
conditions. Two inches down is an estimate. You, of course, do not want
to till after this as you turn up a new supply of weed seed to sprout. Or
you can take advantage of this feature and, after 8 weeks or so of very
hot weather, remove the plastic, turn the soil, and re-apply.
It is very important to have the edges secure so there is no air flow
under the plastic. It is the lack of air movement and resultant heating
that makes this effective. Knowing the sprouting time of the potential
seeds in the soil will be helpful as you will want to leave the plastic
securely in place for at least two weeks longer than you think there will
be new seedlings.
This works very well, is more effective than any weed killer you can apply
(except ones the produce toxic gases in the soil that remain effective for
nearly a year), and is completely safe for all except those young
seedlings. Any critters in the soil have an opportunity to move down into
cooler soil which they do anyway on a really hot day.
After you have done this (all seeds sprouted and plants killed), plant a
good cover such as creeping thyme (or Irish moss) to cover the area with
new plant life and you will have a beautiful walkway between your beds. A
bit of research will reveal many things you can plant there.
Unfortunately, in our area, Pennyroyal dies back during the winter so
leaves a good opportunity for weeds seeds to drift in and get a foothold.
Thyme should, for the most part, keep the weed seeds on the top so the
winter birds can get them. At any rate, the occasional weed that manages
to take root can be easily pulled leaving your walkway weed and grass-free.
You cannot use black plastic for this. Regardless of what you are told,
black plastic does nothing for killing weeds. It blocks the light and
retards growth. When the black plastic is removed, the weeds take over
again. (Weeds in any area are extremely good at their seeds laying in
wait, that is why they are prolific.) This method will work only with
clear plastic . . . the seeds have light and moisture, the clear plastic
holds in that moisture which helps with the super heating process which
kills the seedlings. It also kills anything else that has already been
growing which is why you must cut everything as short as you can; you
don't want any growth shading the ground. Leaving six inches of grass and
then covering it with the plastic will have only minimal or no effect as
it keeps the plastic too far from the soil to allow the super-heating
which is what does the work.
Though this takes several weeks, with the time dependent on the weather
(and types of seeds), it is well worth it. It does a thorough job and is
completely safe to the soil and surrounding plant life. Do remember that
any place where light does not get to the soil will not be affected so
don't weight down the plastic with blocks of wood or rocks; those patches
will grow weeds; a clear plastic bottle with water in it might work if
it's needed (I use fabric staples when something is needed, though the
holes let a bit of heat and moisture out). If you use something to weight
down the plastic, you will have "spots" of growth where it was laying
during the processing time.
Do be aware that any crabgrass that is growing from *under* the sides of
your raised beds will not be affected by this, it will continue to creep
out. This will only kill what is starting from the area covered with the
Remember, the key is *no* air circulation and no chance for moisture to
escape; it is the hot moisture held in that does the trick. I've even
removed the plastic long enough to sprinkle if there is no condensation on
the plastic; just be sure it is again secure to the ground to prevent air
circulation. Moisture, no air circulation and a lot of hot sunny days all
are your friends.
Good luck; I wish you crab-grass/weed free paths.
P.S. You can always use 20 percent vinegar.
firstname.lastname@example.org (Glenna Rose) wrote in
Wow, Glenna, thank you for your detailed suggestions. I have a question
though. I don't think seeds and new seedlings are the source of my weed
problem. The crab grass I am fighting seems to propogate mostly by means
of rhyzomes about two inches below the surfact which are incredibly
tenacious and tough. I have followed them for as far as six feet. I
don't think you cooking recipe will phase them.
I did the weed barrier and hated it. The weeds did not grow from under
it, but after a while a tremendous number sprouted in the decomposing
mulch above it and sent really tenacious roots right through it. You
have the same problem with weeds growing in mulch above plastic,
especially as the plastic degrades and becomes brittle and cracked with
time. I personally prefer a very heavy layer of newspaper with a couple
inches of mulch or bark on top of it. This works quite well at
suppressing weeds and grass for the summer and when it turns into
compost all you need to do is rake it all up and put it in your garden.
Then redo the newspaper and mulch. I live in SW Ohio so it lasted the
summer and I did not have to worry about it till the next spring. In
So. California you might have to do it a couple of times a year. Then
again if you want to spend some money, you could do what I finally did
and put in pavers. They work wonderfully well and if you figure in how
long they last versus what it costs, it is not that expensive per year.
I still have to deal with the occassional weed sprouting between the
pavers, but it is a very minor problem.
Charles Minus wrote:
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