| "Mulch
ado about something!" |
| The
West Australian Newspaper - HABITAT Friday October 18th 2002 |
Words: John Colwill |
"The
best mulch and the cheapest is chopped-up tree prunings"
Most gardeners are aware that mulching is an excellent practice.
Good mulches spread between plants in garden beds will keep weeds
down, shade the soil, help control wind and water erosion, look
good and most importantly save water, lots of water. There is everything
to gain from mulching and nothing to lose.
The key word here is GOOD mulches. At first thought
it may seem that any cover on the soil would save water but that
is not the case. Not all mulches are equal and
not all save water despite what may be said on the bag
or in the advertising.
To understand why some mulches are better than others, it is necessary
to explain what makes a good mulch work. You need to imagine or
have on hand a glass of water with a clear drinking straw in it.
When the sun shines on the soil, surface water is evaporated. If
that is all that happened, there would be no need for mulches but
it is not. The structure of soil is such that a series of tubes
are formed by spaces between soil particles. The water in the soil
is "sucked up" through these tubes by capillary action
in the same way that water rises to a higher level in the straw
than in the rest of the water in the glass.
By this action, water is brought up from within the soil to the
surface where it is evaporated. The process continues until gravity
overpowers the capillary pull. In the meantime, the soil has been
dried to several centimeters deep.
If the tubes can be "broken" by making the holes much
bigger, as in the surface of the glass, capillary action ceases
and the moisture stays in the soil. In order to do this, the mulch
should consist of large coarse particles of irregular shape which
have big gaps between.
The mulch will be even better at saving water if it is non-absorbent
and allows water to pass straight through and into the soil below.
The mulch itself will then quickly dry off which discourages bacterial
action that may otherwise result in nitrogen being taken from the
soil.
A Good mulch can reduce moisture loss from the soil surface by up
to 70 per cent. By contrast, mulches which have lots of fine particles
and therefore a similar structure to the soil do not stop the capillary
action.
Even worse, when mulches such as rotted organic material, manure's,
compost or crushed plant material with added peat or straw are used,
they will absorb water rather than let it through to the plant's
roots below and then simply allow it to evaporate off through the
surface by capillary action.
The retained moisture in these mulches also encourages bacterial
action which may pull nitrogen from the soil, will allow weeds seeds
to germinate and increase the risk of collar rot when material is
placed against the stem of plants. |
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| Different
materials |
- The best mulch and the cheapest is chopped-up tree
prunings, either home made or obtained from your local
authority or tree pruner. The disease risk from using such material
is insignificant.
- Another good water-saving mulch is crushed brick or gravel
with a layer of weed-control mat under it to prevent mixing with
the soil.
- Wood chips and pine bark are acceptable but not stable in exposed
situations.
- Animal manure's, pea straw, mushroom compost and seaweed
are all great soil conditioners but they make
lousy mulches. In addition to not stopping the capillary
action, organic matter in these soft materials is quickly
oxidized and wasted when exposed to the sun. These materials
should either be dug into the soil before planting or spread out
and then covered with, and protected by, a decent layer of good
mulch.
However, soft mulches can be used in the veggie patch and dug
in when the crops are harvested.
- Newspaper is not a good mulch
unless it is in a part of the garden that is watered regularly,
such as the veggie garden. Newspapers laid several sheets thick
quickly dries out and becomes water-repellent.
- Lawn clipping are a bad mulch.
They should be used for making compost.
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| Mulch
myths |
Q: Eucalyptus, bottlebrush and other
native plant material does not break down and should not be used as
mulch!
A: It is true that
most native plant material takes longer to break down but that is
an advantage as far as a mulch is concerned. So to are the natural
oils these materials contain which make the mulch non-absorbent
Q: Mulches are only necessary in
summer!
A: Not so. Mulches
are advantageous throughout the year and should be left undisturbed
to continue their good work.
Q:
Rose are special plants and should not be mulched!
A: Roses may produce special blooms but their
is nothing special about the way they grow. Rose plants benefit from
a good mulch, growing better and healthier on less water with a reduced
incidence of the black spot fungal disease.
Q:
Freshly chipped plant material should be composted before use to avoid
nitrogen draw-down!
A: This
is not normally necessary. Nitrogen draw-down is uncommon and far
more likely to occur with partly decomposed material that hold water.
Where draw-down does occur, it is simply corrected by applying nitrogen,
which is produced by the composting mulch over time anyway.
Q: A little mulch is better than
nothing!
A: Possibly, but
not much better than nothing. To be effective, a mulch should be at
least 50 mm deep, preferably 75mm or more (up to 150mm). Organic mulches
break down over time so it is normally necessary to top up the level
once or twice a year.
Q:
Mulch has to be scraped aside before fertilizer is applied!
A: A good mulch with an open texture will allow
water to pass, dissolve the fertilizer and take them into the soil.
Q: Mulches make the soil water-repellent!
A: Well, some mulches might, in fact some mulches
are them selves water-repellent. A good coarse mulch slows down the
development of water repellency. |
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| Is
it a good mulch? |
- Spread a layer of mulch 50 mm thick over a square metre of
dry ground
- Add a little soil-wetting agent to nine litres of water and
pour over the area.
- Leave an hour or two before checking.
|
| If it is a good
mulch, the surface and most of the mulch should be dry. The soil,
where the plants roots are, should be wet to at least 10 cm deep.
If the mulch is still wet and most of the soil is dry, that mulch
is unlikely to save any water. It may even waste it. |
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MULCH
DELIVERY SALES & FREE MULCH REGISTRATION |
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"Pricing is based on delivery to inner south-east suburbs of Melbourne: We’ll call you and confirm the cost."
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1st Priority Mulch Delivery - PRE PAID * |
| Approx 4-6 m3 delivered (from $121 prepaid)
Approx 6-8 m3 delivered (from $132 prepaid)
Approx 8-10 m3 delivered (from $154 prepaid)
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2nd Priority Mulch Delivery - C.O.D * |
| Approx 4-6 m3 delivered (from $132 C.O.D)
Approx 6-8 m3 delivered (from $154 C.O.D)
Approx 8-10 m3 delivered (from $176 C.O.D)
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3rd Priority @ Convenience Mulch Delivery - PREPAID * |
|
Approx 4-6 m3 delivered (from $66 PREPAID)
Approx 6-8 m3 delivered (from $77 PREPAID)
Approx 8-10 m3 delivered (from $88 PREPAID)
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4th Priority @ Convenience Mulch Delivery - C.O.D * |
|
Approx 4-6 m3 delivered (from $77 PREPAID)
Approx 6-8 m3 delivered (from $88 PREPAID)
Approx 8-10 m3 delivered (from $99 PREPAID)
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5th Priority @ Leisure Mulch Delivery - NO CHARGE * |
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Approx 4-6 m3 delivered @ leisure (from NO CHARGE)
Approx 6-8 m3 delivered @ leisure (from NO CHARGE)
Approx 8-10 m3 delivered @ leisure (from NO CHARGE)
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*
ADDITIONAL DELIVERY CHARGES apply
for areas outside the INNER SOUTH EAST suburbs
of Melbourne. All prices INCLUDE GST |
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MULCH
REGISTRATION CONDITIONS
Please read CAREFULLY!!
1) PRE-PAID Mulch Delivery always
comes 1st priority!
C.O.D. Mulch
Delivery comes 2nd priority.
PRE-PAID
‘convenience’ Mulch Delivery comes 3rd
priority.
C.O.D. ‘convenience’
Mulch Delivery comes 4th priority.
FREE ‘at
leasure’ Mulch Delivery comes last
priority.
2) Choose the APPROX MULCH VOLUME you would like delivered.
(Best performance is achieved with a mulch layer of around 12-18cm deep)
Approx 4-6 m3 - will mulch about 25-45 m2 of garden bed
Approx 6-8 m3 - will mulch about 35-55 m2 of garden bed
Approx 8-10 m3 - will mulch about 45-65 m2 of garden bed
NOTE: Amount delivered is an estimate only & may vary a little.
3) Load can only be left where it can be
tipped off the truck! Good truck access is
required, with clearance of around 3mtrs height right
up to the tipping point, with plenty of overhead clearance
(around 5-6mtrs) for tipping, ie: no overhead wires,
branches, etc.
4) Not all loads will be the same,
type & quality is not guaranteed,
as you are paying for delivery only. Loads will vary
somewhat in type & quality, from fine to course,
from mostly woodchip to mostly foliage, however, it’s
nearly always a fairly even mix, it all depends on
the type of plant being mulched (hard or softwood,
evergreen or deciduous, stringy palm & fronds,
vines, etc.) & the adjustment & sharpness
of the chipper blades. However, bear in mind that
the variation of small & large particles is the
secret to the very best mulch.
5) Excess mulch is NOT the responsibility
of Aardvark or the Tree Contractor and will not be
removed! It may be an idea to chat with
neighbours 1st about sharing a load before registering?
Additional condition for convenience / at leasure delivery
6) For FREE deliveries there is NO GUARANTEE that
you will EVER receive a load of mulch! It is a standby
system for participating Tree Contractors who may
need to empty the truck in your area, but the final
decision is always up to the Contractor. PAID delivery
gets priority!
7) QUANTITY WILL VARY from as little as 5 up to
12 or more cubic mtrs (about 5-12 small trailer loads)
and CANNOT be specified.
8) The load will be dropped off with LITTLE OR NO
NOTICE, so a drop off point that is accessible at
all times is required.
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MULCH REQUEST FORM
(* required)
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Great article on why recycled tree mulch
is the best
mulch to use on your garden, read what John Colwill,
the Gardening Guru has to say about this fantastic product! |
Palms make the most excellent composting
& water saving mulch, rough, course irregular
particles that don't break down too quickly. Thankfully,
many gardeners are removing these unsuitable plants from
their landscapes.
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If you are having a palm removed
make sure you keep the mulch.
ALL prunings & green waste
should be recycled back on your landscape as mulch or as
compost.
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FEED THE SOIL- NOT THE PLANT
You will be recycling all the macro & micro nutrients
that your plant has extracted from the soil back into your
landscape.
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