Articles for week ending 10th NOVEMBER 2007
Written by Wally Richards. [Photo]
There are many ways to control those unwanted plants
that grow in our gardens and lawns from hand weeding to chemical weed killers.
The definition of a weed is any plant growing where you do not want it to grow
and is not necessarily the plants we commonly call weeds. It maybe that you have
grown some flowering plant for its virtues to find over the years that the original
plant self-seeded and now pops up all over the place. You either live with it
or you go hell bent on eradicating every trace of it.
The best way of controlling
any weed is to cut it off just below soil surface, before it seeds, and leave
it on the bare soil to be absorbed back into the soil food web. You have by doing
this, provided two soil enriching aspects, the roots left undisturbed, rot in
the soil feeding millions of soil organisms without disrupting the beneficial
fungi chains in the earth. The green top provides food for the surface feeders
who quickly break down the weed and enriching your gardens.
For gardeners that
know about this natural system, they cherish the appearance of weeds as each type
provides elements and minerals that will make for better gardens.
is of course, not to let the weeds get too big or produce seeds.
In my book
Wallys Down to Earth Gardening Guide I pointed out that no weed
or plant can survive if it is denied foliage for an extended period of time. All
plants gain their energy from the sun through their leaves. Stop them from obtaining
energy and they have to fail and die.
Take oxalis for instance,
it is a bulb that throws up a set of leaves, gains energy from the sun and produces
hundreds of bulblets or baby bulbs. If you take a heaped tablespoon of baking
soda and add it to a litre of warm water, stir to dissolve, then add one mil of
Raingard, you have made a potent dehydrator of oxalis foliage which does not harm
other types of plants. If you spray this formula over the oxalis foliage on a
sunny day when the ground is on the dry side the leaves of the oxalis will shrivel
and die. It has not killed the bulb which will then produce another set of leaves.
As soon as these appear you either apply the same solution or cut them off at
ground level. If done quickly enough at the emergence of the new leaves the bulb
has not gained energy but has weakened instead. Again it will try to produce leaves
which should be quickly removed. At some point of time the bulb does not have
any more energy left to produce foliage and it rots in the soil. Goodbye oxalis.
is a further aspect to the oxalis problem and that is all the baby bulbs attached
to the now dead parent, if you disturb the soil you will bring these babies nearer
to the surface where they will also produce leaves to start the cycle over again.
What you do instead is cover the soil with a layer of compost and plant any new
seedlings into this layer. This action further buries your oxalis problem. Do
not disturb the soil and when you flowers or vegetables are finished or harvested,
just cut them off at ground level and cover the area with more compost. Simple
Chemical weed killers should be avoided at much as possible
as they do a lot of damage to the health of the soil, environment and ourselves.
There is also another good reason to avoid them as the price of many of them has
become very expensive. Glyphosate, the most common weed killer these days sold
under various trade names such as Roundup does not dissipate when it hits the
soil and has a half soil life of 6 months or more dependant on the soil type.
It kills soil life and worms hate it. It gets into your food crops and ends up
as another chemical poison in your food chain. I believe that one day we will
come to realise that Glyphosate is as bad if not worse than many of the banned
chemicals such as DDT.
Lets face it, it has only been over the last 50 odd
years that we have had chemical weed killers to use in our gardens and farms and
before this more natural things were used, many of which can be far more effective
than the chemical and less damaging to the environment or our health.
gorse, black berry and other woody similar plants can be eradicated with garden
lime. Change the pH making the soil more alkaline and the offending weeds fail.
Ideally you cut the gorse or black berry down to near ground level and dose the
surrounding area with a good amount of lime. You can also treat the stump with
diesel. The lime will prevent regeneration of the gorse etc. Simple, cheap and
effective. Diesel, sump oil etc, once were used to mark the lines of rugby fields
in days gone by. The line would be painted with sump oil and no grass or weeds
would grow in that line for a long time.
If you have a waste area where you
want nothing to grow for a long time it could be a good cheaper solution.
lady gardener rang me during the week and gave me a tip about that horrible weed,
She has used the following solution and told others with a wandering
jew problem about it, all of whom have cleaned up the problem in a short period
Go to a grocery wholesaler such as Toops and buy a 25 kilo bag of
table salt, which will cost you between $10 to $15.00. Broadcast the salt over
the area where the wandering jew is growing, its cheap so throw it on. You will
find that the weed dies off leaving bare ground. Some new emergence will then
occur and you spot treat these with a handful of salt. Later rake the area to
remove the stubble and then you can lime the area and apply Magic Botanic Liquid
to bring the soil back for planting up in a preferred plant. If you have other
plants growing in the area they will likely die also but well established trees
and shrubs should not be unduly affected. Now $15.00 worth of salt goes a long
way and is cheaper than a little bottle of chemical weedkiller for $30 which does
not go far.
If you have pavers and weeds grow in the cracks just sprinkle some
of your salt.
Another one is sulphate of ammonia which also burns out weeds.
I tried this out the other week on low weeds growing in a gravel drive. Sprinkled
the sulphate of ammonia over them and now they are all brown and dead. Ideally
you should lightly water the weeds about half an hour prior to applying the sulphate
of ammonia so there is a little moisture to start the burning action. The advantage
of sulphate of ammonia is a short residue period, unlike table salt which is much
In your kitchen you already have a couple of neat, environmently friendly
weed killers, vinegar and cooking oil. These can be sprayed over the foliage of
weeds on a sunny day when the ground is on the dry side to burn off the weeds.
Dependant on the type of weed you can dilute the two products with water to make
them go further and be more economical. You need to experiment a bit to find out
what dilution rate works best for each type of weed and to assist mixing with
water you are best to add some Raingard.
Once again buying either a cheap cooking
oil or vinegar in bulk, works out very economically on the purse and you are doing
far less damage to the environment or your own personal health.
should be cut low with a weed eater before applying any of the more natural products
suggested above. This reduces the amount of product you need to use and gives
a quicker result.
One thing to remember is that these methods are non-selective
and whatever you treat, preferred plants or weeds will be affected. Well established
trees and shrubs should be fine.
If you want the dead weeds to disappear faster
spray them with Thatch Busta.
Any Problems ring
me at 0800 466464 (Palmerston North 3570606)
Web site www.gardenews.co.nz