Stubby wrote:
Black plastic film will work. Lanscape fabric is awful because weeds,
including crabgrass, will come up through it.


Andy adds:

I have used both black plastic and landscape fabric, and observed
the
results for many years.
Stubby is correct.

My best results were black plastic with gravel over it for at
least two
inches. This protects the black plastic from sunlight, which will
degrade
it in one or two years. With gravel over it, after 20 years it is
still intact.
Gravel doesn't blow away. And with two inches, you can walk on it
without tearing up the plastic underneath.... I like the small pink
gravel,
but I have also used the large white rock....

Regarding the soil underneath ----- With black plastic, you get
the
same effect as if you put down a concrete slab, or a concrete or
asphalt driveway. The soil underneath remains stable, and does NOT
dry out. In fact, it stays more stable since most of the "drying
out"
would occur from evaporation from the surface, and that is virtually
eliminated. Same thing as happens in roadways and parking lots.
Things are better. The soil moisture difufuses IN from the sides and
causes problems only at the edges, such as the edge of a foundation
of a house...... Underneath is no problem. However, bugs and ants
can live underneath. Also gardening sites warn about fungus. I have
seen bugs -- I haven't seen fungus.

Regarding weeds. All that has been posted here by the other
posters about weeds growing in landscape fabric is true......

Presently, I use black, 4 or 6 mil black plastic to block off the
big areas.
I cover it with gravel. Or mulch, if I don't mind replacing it a
couple times
a year since it washes and blows away.

If I want a bush, I remove the gravel and plastic for, say a two or
three
foot circle. Dig the hole, put in some compost, put in the bush and
then
put landscape fabric to cover the hole. That way I can water the bush
effectively until it recovers, and the rain will have a place to run
in
under the plastic. I have had very little weed growth in these small
areas. Apparently the bush takes the nutrients before the weeds, but
I'm not sure ----- it just isn't much of a problem.

The area is North Texas , where the summers are always in drought
and
the winter and spring is usually pretty wet. The soil is mostly clay,
and the
temps are above 100 in summer and almost never go below 32F at any
time..... That stuff is probly important, tho you can get more
thorough
advice from your local ag extension service....

Andy in Eureka, Texas