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Gardeners are understandably concerned about their gardens following the
recent flood events. It is time to take a deep breath and calmly
consider what we know about soil and plants, then take positive steps to
help get our gardens growing again.
Sewage Waste
Many gardeners are concerned about possible soil
contamination from flood water. Most of these concerns are unwarranted.
Soil organisms like fungi and bacteria use things that we regard as soil
contaminants as food.
Concerns expressed in the media and by some authorities in relation to
vegetable gardens primarily relates to sewage contamination. Do not
harvest and eat leafy green crops from vegetable gardens that have been
covered with water. Most of these crops will have wilted and died anyway
as they do not stand waterlogging.
Gardeners throughout the world use composted sewage waste for soil
improvement. Council and shire authorities throughout Australia
routinely use composted sewage waste in public parks, street median
strip plantings and on sports ovals. They just do not tell local
constituents. However unpleasant it may sound, sewage contaminated flood
water will not cause long term damage to your garden.
Other Contaminants
Your best defence against all contaminants
is good biological soil life. Gardeners know that worms are a great
indicator of good soil health. If you have worms, the soil will be fine.
The most common types of soil testing available from water and soil
laboratories check for nutrients, not oil, petrol, heavy metal or other
contaminates. You cannot ask a soil testing company to test for
everything! Simple soil nutrient tests cost around $250. Testing for
possible soil contamination will cost much more and is really simply not
warranted in most instances.
Vegetable Gardens
If you remain concerned about your vegetable
garden, you may be better to spend your $250 starting again. After all,
if you have your soil tested and they find some contamination (remember
it could have been there before the flood, but you just did not know)
the recommendation will be to start with new soil.
Remove the soil from vegetable garden areas. Build a new no dig garden
in its place, make compost or import a soil blend from your local
landscape supplier and add compost to start to rebuild your soil
fertility.
Planting for a Quick Harvest
• Remove all
dead or decaying plant material from flooded gardens. This can be added
to the compost.
• Remove anything that is wilting
(tomatoes, eggplants, capsicums, pumpkin vines, garden shrubs and
trees,). Wilting
is one of the first
signs of root disease and it is not worth trying to save these plants.
• Aerate the soil with a garden fork. Look for signs of life within the
soil – worms are very sensitive to contaminants,
so their presence is a good barometer of soil health.
• Check the soil pH. Waterlogging can cause the soil to become
temporarily acidic. There is no need to rush to apply
lime. The pH will adjust itself in time. Have some liquid fertiliser and
seaweed extract on hand to treat new seedlings
and any existing plants you intend to save.
•
Replant by sowing seeds of fast maturing crops like rocket, lettuce and
beans or plant seeds or seedlings of cherry
tomatoes.
• Plant pots of parsley, chives, garden
sorrel, mint and basil. Look in the herb section in your local nursery
for other
perennial salad greens and
herbs that will give you an instant harvest.
Not Ready to Replant?
If you remain concerned about soil
contamination or are not ready to plant, sow seeds of a green manure
crop like cowpea or lablab (you can get seed from produce stores or
on-line from Green Harvest). If you have old packets of flower or
vegetable seeds (especially those where the packaging has become wet)
sow them as a green manure.
Buy some cheap dried beans (the type you soak and put into stews and
soup) from the supermarket and sow them as a green manure. Grow quick
leafy greens or other vegetables in pots or containers using potting mix
mixed with some coir peat, blood and bone or other organic fertiliser.
Trees and Shrubs
Many trees and shrubs cope with temporary
inundation, but many of those that cannot be saved will already be
showing signs of deterioration. Grevilleas, salvias, coleus, gardenias,
hibiscus and other shallow rooted understorey plants are less likely to
be saved. Palms with brown foliage are unlikely to recover.
Bottlebrush (callistemon), lillypillies, tea trees (leptospermum)
paperbarks (bottlebrush), rainforest plants, roses and hedges are likely
to be fine, providing you can remove mud and silt.
• Where possible wash mud and silt from the foliage of garden trees and
shrubs. This may be a way of using relatively
clean (but undrinkable) tank water that has been contaminated with flood
water and needs to be emptied. If the
mud is caked hard and a jet of water from the hose will not move it, it
may be better to prune plants back and let
them reshoot. Do not use powered water blasters on plants. It will strip
the bark and kill any plants that might
otherwise recover.
• Applying products like Yates
Anti-Rot is a safe option for treating significant trees and shrubs that
remain alive, but
are likely to fall
victim to root rot diseases in the months ahead. Prioritise the plants
you want to try to save.
Remember
that buying new plants is often cheaper than spending money on plants
that will always be unthrifty or
misshapen regardless of what you do.
• Water
plants with seaweed extract to help build disease resistance and
encourage development of new roots.
What
Gardeners Can Do To Help Others
Not everyone is able to help out with
the physical task of clearing homes and
properties, but gardeners whose properties have not been flood affected
can help out in unique ways.
• Share the surplus
from your vegetable garden and fruit trees with flood affected
households.
• Grow vegetables seedlings to give to
others to replant vegetable gardens.
• Take
cuttings of plants from your own garden to share with others.
• Visit less experienced gardeners and provide advice as to what plants
might be saved or species that could be used
when replanting.
• Make compost to share with
others trying to get gardens re-established.
•
Propagate native plants for community replanting efforts.
• Clear surplus garden tools and equipment from your garage or shed so
that others can get back to work in their
gardens as soon as possible.
Melioidosis
Gardeners cleaning up flood ravaged homes and
gardens should be mindful of the potential for simple scratches and cuts
to develop into a life-threatening medical condition called melioidosis.
Melioidosis bacteria (Burkholderia pseudomallei) lives within the
subsoil. During the wet season in northern Australia or elsewhere after
flood events, it is found in surface water and mud. Infections are more
common in north Queensland and the Northern Territory, but recent flood
events have widened the risk. An increase in the incidence of the
disease occurred in south east Queensland after the 1974 floods.
Melioidosis bacteria enters the body primarily though simple cuts and
abrasions. Common symptoms include chest, abdominal pain and coughing or
blood poisoning at the site of the injury. Gardeners with other
underlying medical conditions are particularly at risk.
Always wear gloves and sturdy, waterproof footwear when you garden.
Shower after working outdoors and pay attention cuts and infection. Keen
gardeners should be particularly mindful of the symptoms of melioidosis.
Make a note to ask your doctor about melioidosis next time you visit.
Starting Over
Where can I purchase inexpensive plants to get
my garden started again?
Grovely TAFE Nursery
The nursery at Grovely TAFE is accessible
from Woking Street, Grovely. The nursery sells plants propagated by
horticulture students at very reasonable prices during Saturday plant
sale days run several times each year. A diverse range of native and
exotic trees, shrubs and groundcovers are sold. Phone 3354 5504 to find
out when the next plant sale will be held.
Kumbartcho Community Nursery
15 Bunya Pine Court, Eatons
Hill 4037 This fully functional community nursery has a wide range of
native plants. Volunteers provide information and advice about growing
local native plants and propagate a wide variety of native species that
are sold at cost to members of the public.
The nursery is open to the public at the following times: Thursday
9am-3.00pm, Friday 9am-3.00pm, Saturday 8.30am till noon, Sunday 8.30am
till noon.
Prices - $1.50 forestry tube, $3.00 larger pots inc GST
Phone: 07 3264 3953 for more information
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