Now In: Mulch Guide
Mulch can be separated into two groups, organic and inorganic.
Compost is one of the best mulches for providing benefits
to the soil, but that rich medium also provides a great place
for weeds. Some compost is not very attractive. If appearance
is important, use compost as a soil amendment and find a more
visually pleasing material to cover it.
Lawn Clippings are in steady supply during the mowing season,
but let them dry before using. Spread them thin. Dry grass
clippings will mat if spread too thickly. Never use grass
clippings from a lawn that has been treated with herbicide.
The best bet may be to add untreated clippings to your compost
pile or use as mulch in the vegetable garden. Rich in nitrogen,
grass makes a good vegetable mulch.
Leaves are plentiful and free in many areas. They look and
work better if partially ground and decomposed; otherwise
they blow away or mat down when wet. Matted leaves form a
barrier that prevents air and moisture from getting to the
soil below.
Sawdust is easily available in many areas. Use sawdust that
is at least one year old if possible. Fresh sawdust can deplete
nitrogen if mixed with the soil. However, sawdust on top
of the soil should not present a nitrogen concern. Just keep
an eye on the plants, and add a nitrogen-rich fertilizer
if necessary.
Wood Chips or Shavings are visually pleasing and provide all
the characteristics of good mulch. Like sawdust, it is advisable
to use older, decomposed material. Wood mulch that has not
been properly aged or turned regularly can contain toxins
and acids that are harmful to young plants. Fungal contamination
can also occur with unseasoned wood mulch.
Bark is sold as chunks, nuggets, or shredded. Bark is one of
the most attractive (and more expensive) mulch materials,
so it may be best used in more visible areas. Pine, cedar,
and cypress are the most common varieties. In addition to
its appearance, bark provides good weed prevention and moisture
retention. Plus, bark nuggets will last for years.
Straw is the leftover stem portion of harvested grain. It is
lightweight and therefore not always easy to apply. It tends
to blow around. It decomposes quickly and therefore needs
replacing more often than other mulches. Its appearance may
not make it a top choice for the landscape. However, straw
does make a good cover for newly-seeded lawn areas.
Hay, the stem portion of grasses, is often confused with straw.
Hay is likely to contain weed seeds, so use it with caution.
Both straw and hay are good plant nutrients and work well
in the vegetable garden where weeds can easily be pulled.
Pine Needles are sold in bales like straw which makes them
relatively easy to transport and apply. They are long lasting
and attractive.
Topsoil that is sold at garden centers is basically packaged
compost, a good soil amendment.
Manure may also be best used as a soil amendment. If you use
it as mulch, make sure it is dry and well rotted. Odor will
not be an issue, but the appearance may leave something to
be desired. Manure often contains seeds — a good reason
to consign it to the compost pile.
Newspaper or Shredded Paper is readily available, and paper
decomposes quickly. Newspaper can be used in sheets or shredded.
Paper is another mulch best used in the vegetable garden,
unless you plan to cover it with another more attractive
organic mulch. Colored ink is not good for plants, so don’t
use the comics or magazines.
Inorganic Mulches are man-made. They work well and seldom
need replacing, but they offer nothing back to the soil.
Recycled Rubber is a great landscape alternative to bark or
stone. Made from 100% recycled rubber product, It is safe long-lasting
and natural-looking. Rubber mulch does the things you want
mulch to do: helps retain moisture, moderates soil temperature,
controls weeds and looks good in your landscape. Available
in various natural shades to provide the look of wood bark,
rubber mulch will not fade. It is heavier than bark mulch and
less likely to blow away or float away during a heavy rain.
Rubber mulch only needs to be applied to half the depth of
traditional wood mulch. This product is excellent for playgrounds
and is approved by the American Society for Testing and Materials
(ASTM) when maintained at a 6" depth (compared to a minimum
depth of 9" for wood mulches).
Plastic warms the soil, plus blocks air and water. Plant growth
is accelerated by the added heat and moisture retained underneath
the mulch layer. Since plastic is solid, moisture must be
provided by an irrigation system
Black or clear plastic can be used. underneath or by careful
hand watering. Usually sold in rolls, black or clear plastic
can be used. Black is impervious to light, while clear plastic
has been known to let weeds germinate and grow beneath. On
the downside, plastic can overheat the plant’s roots
or retain too much moisture, particularly if the plastic is
covered with a layer of organic mulch for appearance sake.
Plastic will freeze, so you may need to take it up in the fall.
If used on slopes, any material placed on top of plastic will
wash away or slide off. Plastic is well-suited for use in vegetable
gardens.
Brick or Stone offers a neat appearance but may not blend with
every landscape design. They offer some weed control. Brick
and stone (especially lighter shades) will reflect heat back
up towards plants, which may be harmful. This mulch is certainly
long lasting. Be careful — if pieces are strewn into
the lawn, they can become potential hazards when mowing.
Landscape Fabric (known as geotextile) is purchased in rolls
and provides good weed control. Plus, unlike plastic, the
fabric allows air and moisture to penetrate into the soil
and plant roots. Overall, it's the best inorganic mulch for
long-term use. Roots can become enmeshed in the fabric, making
removal difficult, so be sure to remove weeds as soon as
you see them.
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