ORGANIC BASICS
42
manganese, copper and iron that are essential to plant
growth. Lastly, oxygen absorbed from air helps prevent
waterlogging occurring in heavy rains.Tap water and plants
As mentioned, municipal tap water has been treated
with additives to ensure it is safe to drink. It contains
chlorine and fl uoride, which can build up in plant leaves
and cause burnt leaf margins (in a worst case scenario).
Also, sodium may be added as a water softener; sodium
is toxic to plants and damages soil structure.
Water sitting in copper pipes with lead-based solder
or passing through brass tap fi ttings may contain
small amounts of lead. While frequent testing ensures
Australia’s water is safe and meets strict water quality
guidelines, excessive use of tap water on sensitive
plants such as indoor plants and fruit trees may have
negative effects on their health and growth. None of
these are crucial, you won’t kill your plants from using
tap water, it’s just that natural rainwater is preferred.Environmental benefits
Of course there are many other benefi ts of collecting your
own rainwater, which we have covered over the years in
Organic Gardener, but which are becoming more important
as our continent dries. Installing a rainwater tank offers
greater water security and in times of restrictions –
already in place for many towns and cities – it may be
the only legal source of water for your garden given that
outdoor watering is usually the fi rst stage of restrictions.
While tanks have initial set-up costs, they result in
lower water bills in the long-term – and the survival
of your garden. Drinkable tap water is also a precious
resource that must be stored in dams, run through
treatment plants and piped to our homes, requiring
infrastructure, maintenance and power. That’s not tomention the massive costs of desalination plants now
providing back-up supplies in some states.
As the population grows, the water supply will need
to be expanded. Using captured rainwater reduces mains
water requirements and lowers our environmental
footprint. Installing a rainwater tank also lightens
strain on the stormwater system, and helps minimise
run-off and fl ooding during heavy rain events.Clean tanks
Tanks are an excellent way to capture rainwater from
the roof of any structure. However, just as rain absorbs
benefi cial elements from the atmosphere, it can also pick
up less desirable ones. Over time, roofs accumulate dust,
debris, bird manure and atmospheric pollution. These
build up when there’s no rain, then are washed into the
tank with the fi rst rainfall. The solution is to install a
fi rst fl ush device onto the water storage tank. It fl ushes
the roof clean by diverting the initial rainwater away
from the tank, taking any pollutants present with it.
There are other times to use a fi rst fl ush approach.
Brass taps and hose fi ttings can contain traces of lead,
so it’s common sense not to use water which been
sitting in the garden tap or pipes for some time; run
the water for a few seconds fi rst. Using a water fi lter
will also free your water from some pollutants.
Keep your tanks clean and healthy by following
simple guidelines: cleaning gutters every three months;
installing mosquito mesh and maintaining it; fl ushing
out the u-tube; and maintaining pumps and fi ttings.
Fully clean out the sludge (into the compost not
into waterways) every two to three years.
In the garden, nature usually knows best and
rainwater is no exception. Save money, help the
environment and benefi t plants by using rainwater
where possible. Next they’ll be calling it a superfood!If you are keen on
mixing your own garden
preparations, such as
nettle tea, biodynamic
preparations or liquid
compost, rainwater
is preferable, as
chlorine in tap water
may kill off the good
microorganisms.Right: Water plants at roots
to limit dehydration.
Far right: Tank water has
benefits for your garden.PHOTOS: LEFT: ALAMY/RIGHT: KINGSPAN WATER TANKS (KINGSPAN.COM)