Mulching enriches and protects soil, helping provide
a better growing environment. In your backyard mulching
is one of the simplest and most beneficial practices
you can use in the garden. Mulch is simply a protective
layer of a material that is spread on top of the soil.
Mulches can either be organic -- such as grass clippings,
straw, bark chips, and similar materials -- or inorganic
-- such as stones, brick chips, and plastic.
Both organic and inorganic mulches have numerous
* Protects the soil from erosion
* Reduces compaction from the impact of heavy rains
* Conserves moisture, reducing the need for frequent
* Maintains a more even soil temperature
* Prevents weed growth
* Keeps fruits and vegetables clean
* Keeps feet clean, allowing access to garden even
* Provides a "finished" look to the garden Organic
mulches also improve the condition of the soil.
As these mulches slowly decompose, they provide organic
matter which helps keep the soil loose. This improves
root growth, increases the infiltration of water,
and also improves the water-holding capacity of the
soil. Organic matter is a source of plant nutrients
and provides an ideal environment for earthworms and
other beneficial soil organisms.
While inorganic mulches have their place in certain
landscapes, they lack the soil improving properties
of organic mulches. Inorganic mulches, because of
their permanence, may be difficult to remove if you
decide to change your garden plans at a later date.
Therefore, this tip sheet is limited to the use of
You can find mulch materials in your own yard! Lawn
clippings make excellent mulch. While not particularly
attractive for a flower bed, they work wonderfully
in the vegetable garden. The fine texture allows them
to be spread easily even around small plants.
However, grass clippings are becoming scarce because
of the increased popularity of mulching lawnmowers
that provide many of the same benefits of mulching
to lawns. Newspaper, as a mulch, works especially
well to control weeds. Leaves are another readily
available material to use as mulch. Leaf mold, or
the decomposed remains of leaves, gives the forest
floor its absorbent spongy structure. Compost makes
a wonderful mulch if you have a large supply. Compost
not only improves the soil structure but provides
an excellent source of plant nutrients. Bark chips
and composted bark mulch are available at garden centers.
These make a neat finish to the garden bed and will
eventually improve the condition of the soil. These
may last for one to three years or more depending
on the size of the chips or how well composed the
bark mulch is.
Smaller chips tend to be easier to spread, especially
around small plants. Depending on where you live,
numerous other materials make excellent mulches. Hay
and straw work well in the vegetable garden, although
they may harbor weed seeds. Seaweed mulch, ground
corn cobs, and pine needles can also be used. Pine
needles tend to increase the acidity of the soil so
they work best around acid-loving plants such as rhododendrons
When to Apply Mulch Time of application depends on
what you hope to achieve by mulching. Mulches, by
providing an insulating barrier between the soil and
the air, moderate the soil temperature. This means
that a mulched soil in the summer will be cooler than
an adjacent unmulched soil; while in the winter, the
mulched soil may not freeze as deeply. However, since
mulch acts as an insulating layer, mulched soils tend
to warm up more slowly in the spring and cool down
more slowly in the fall than unmulched soils.
If you are using mulches in your vegetable garden
or flower garden, it is best to apply them after the
soil has warmed up in the spring. Cool, wet soils
tend to slow seed germination and increase the decay
of seeds and seedlings. If adding additional layers
of mulch to existing perennial beds, wait until the
soil has warmed completely. Mulches used to help moderate
winter temperatures can be applied late in the fall
after the ground has frozen but before the coldest
temperatures arrive. Applying mulches before the ground
has frozen may attract rodents looking for a warm
over-wintering site. Delayed applications of mulch
should prevent this problem as, hopefully, the creatures
would already have found some other place to nest!
Mulches used to protect plants over winter should
be loose material such as straw, hay, or pine boughs
that will help insulate the plants without compacting
under the weight of snow and ice. One of the benefits
from winter applications of mulch is the reduction
in the freezing and thawing of the soil in the late
winter and early spring. These repeated cycles of
freezing at night and then thawing in the warmth of
the sun cause many small or shallow rooted plants
to be heaved out of the soil. This leaves their root
systems exposed and results in injury or death. Mulching
helps prevent the rapid fluctuations in soil temperature
and reduces the chances of heaving.
What do I hope to achieve by mulching
* Weed control Domestic
* Moisture retention over Large areas
* Soil improvement
How large is the area to be mulched?
How much mulch will I need to cover the area?
Mulch is measured in cubic Meters. As an example,
if you have an area 10 Meters by 10 meters and you
wish to apply 100 mll of mulch, you would need 1
Determine what mulch material to use and purchase
or accumulate what you need.
Mulch can often be purchased bagged or bulk from
garden centers. Bulk may be cheaper if you need
large volumes and have a way to haul it. Bagged
mulch is often easier to handle, especially for
smaller projects. Most bagged mulch comes in 3-cubic-feet
Bark mulch 2-4 inches Smaller chips are easier to
spread, especially around small plants. Excellent
for use around trees, shrubs, and perennial gardens.
When spreading mulch around trees, keep the mulch
an inch or two away from the trunk. A couple inches
of mulch is adequate. There is no need to apply the
mulch 6 or 8 inches high, as often is seen. Wood chips
2-4 inches Similar to bark mulch. If using fresh wood
chips that are mixed with a lot of leaves, composting
may be beneficial. Leaves 3-4 inches Best to chop
and compost before spreading.
If using dry leaves, apply about 6 inches. Grass
clippings 2-3 inches Thicker layers tend to compact
and rot, becoming quite slimy and smelly. Add additional
layers as clippings decompose. Do not use clippings
from lawns treated with herbicides. Newspaper 1/4
inch Apply sheets of newspaper and cover lightly with
grass clippings or other mulch material to anchor.
If other mulch materials are not available, cover
edges of paper with soil. Applying on a windy day
can be a problem. Compost 3-4 inches Excellent material
for enriching soil. Bark mulch and wood chips are
sometimes used with landscape fabric or plastic. The
fabric or plastic is laid on top of the soil and then
covered with a layer of bark chips.
A caution to this practice: while initially the plastic
or fabric may provide additional protection against
weeds, as the mulch breaks down, weeds will start
to grow in the mulch itself. The barrier between the
soil and the mulch also prevents any improvement in
the soil condition and makes planting additional plants
more difficult. For Sources of Mulch Check under mulches
or garden centers or nurseries in the Yellow Pages.
Your community may also have wood chips from the removal
of street trees that are available free to residents.
On the Farm Farmers use mulches in many ways. Conservation
tillage is a common practice that creates a mulch
on the soil surface. Unlike the once common practice
of plowing all crop residue into the soil, conservation
tillage leaves the crop residue on top of the soil.
These pieces of corn stalk, straw, or bean stems help
protect the soil against wind and water erosion. Corn
crops harvested for the grain return large amounts
of residue to the soil surface and are more effective
in preventing soil erosion than crops with less residue
such as soybeans.
Mulching is a common practice among strawberry growers
in northern climates. In this situation, mulch is
used to protect the crop during the winter and to
help prevent early blooming of the plants. Plants
that bloom too early are more likely to be damaged
by spring frosts. The mulch also helps keep the berries
cleaner, protecting them from soil splashing on them
in the rain. Inorganic mulches are also widely used
in commercial agriculture. Clear plastic mulch can
be particularly beneficial in giving warm season crops
a head start. The clear plastic acts as a mini-greenhouse,
warming the soil underneath it. Particularly where
early sweet corn brings a premium price, this practice
can give a grower a couple of weeks head start.