All about a weedy garden

There are several weedkiller methods that are offered at Barossa Mitre 10 with a promise to curb garden invaders. It sometimes feels easiest to grab a product and attack but for best results consider the best product for the situation, the best practice for the situation and an analysis of the weeds in the situation. There are quite a few weed tips before you grab the sprayer.


The first step in being able to choose the right weed killer to use is to identify the weeds you are fighting. Herbicide products are weed specific meaning that killing one weed may not faze another. These selective weed killers are perfect to use with fine-leaf lawn grasses overrun with weeds. Applying a broadleaf weedkiller to your lawn will wipe out all broadleaf weeds but not harm your grass. Be warned though some weedkillers including weed and feed although fabulous at cleaning up your lawn have the potential to drift in the breeze and damage or kill nearby plants.


Often the impact of the weed control product goes beyond the weed you are trying to control, responsible use is something you also need to consider. Product labels provide critical information about how to safely handle and use the product. Restrictions may mean it is not suitable for your application.

Weedkiller does not work better or become stronger if you double the amount of product you use. Gyphosate360 at 40ml per 5 litres will not magically become Glyphosate720 if you add 80ml to 5 litres, it will remain the same strength, you will just waste 40ml of your weedkiller.

Satisfaction with any product comes when you have reasonable expectations about results. An assumption of one application killing everything you want, with no negative results and very little effort is probably not going to happen. Woody weeds are probably going to take a couple of rounds to get rid of them, they may be very thick on the ground, the dew may not be quite dry, the spray may miss them and you will have to go back over it.


Weedkillers, no matter if organic or non-organic take time to show results. You may see dieback within hours but others work slowly and may take many days before any result is apparent. Temperature plays an important part in the reaction of many weeds to chemicals, the colder the weather the slower the results. Allow at least one week for the weed killer to reach the roots before mowing.


ORGANIC WEEDKILLERS – Organic herbicide contains natural plant oils pelargonic acid (nonanoic acid) is a fatty acid that occurs naturally as esters in the oil of pelargonium plants. It is produced sustainably from biologically based raw materials using an environmentally sustainable method of extraction. These oils once converted to acid acts on the plant foliage causing it to quickly dehydrate and collapse. Most are very effective and fast acting with results apparent within hours. Certified organic products are safe to use if you are an organic gardener with no lasting soil residues. It can also be used safely in environmentally sensitive areas where children and pets play or where animals graze, after the spray has dried.

BROADLEAF WEED TYPE – This weedkiller will kill most broadleaf weed varieties without being harmful to grass. Not suitable for buffalo or kikuyu lawns. Some examples available of this type of weed killer are Kleen Lawn, Weed and Feed and Lawn Master.

NON-SELECTIVE -The active ingredient being Glyphosate is an non-selective weedkiller and can be used on lawns. There are varying strengths of Glyphosate; some have other ingredients added for it to become a soil sterilant, sterilising the top layer of soil so nothing will grow. Glyphosate weedkillers are Roundup, Zero, Brunnings Weedkill and an example of a soil sterilant is Bantox, all available at Barossa Mitre 10.

GRASSY WEED TYPE – This weedkiller is not safe to use on lawns. Mainly used in garden beds, paths or driveways.

SEDGE OR NUTGRASS TYPE – A very specific killer, one called Sedgehammer is very effective and safe to use on most grass lawns. Sedgehammer is an example of this weedkiller


Glyphosate is a broad-spectrum herbicide that works by inhibiting an enzyme found in plants; this enzyme is not found in humans. The Australian Pesticides and Veterinary Medicines Authority (APVMA) approved products containing glyphosate and it will remain registered for use in Australia. Australian law requires appropriate warnings on the product label which includes first aid and safety directions detailing personal protective equipment when handling and using products containing Glyphosate. Personal protection starts with rubber boots, long pants, long sleeves, and gloves with safety glasses and a respirator or face mask.


  • No rain or irrigation in the first 3 – 4 hours of spraying or until dry on the leaf.
  • Do not mow before using spray.
  • You must wait for weeds to be dry from early morning dew and spray before moisture comes in the late afternoon, giving you a window from approximately 11am to 2pm to spray.
  • The warmer the weather the quicker there will be results as the weeds are actively growing. If spraying in cold weather the results will be much slower as the weeds grow a bit slower and may have to be sprayed twice.
  • The younger and more tender the weeds the more effective the weedkiller will be.