Yes, it's generally better to spray weeds before pulling them (after allowing the herbicide time to work) to kill the roots effectively, preventing regrowth, but only if you plan to use a chemical killer; otherwise, manual pulling (especially when soil is damp) or other methods are better to avoid spreading seeds or leaving roots behind, as spraying dead weeds won't stop new ones from sprouting. Spray first to kill the plant systemically, then remove the dead debris; spraying bare soil after pulling won't stop future weeds.
If you're looking to get rid of them, you'll want to spray them instead of pulling them by hand. Spraying weeds requires less effort, allows you to cover a larger area, and is more effective since herbicides can quickly kill them. Meanwhile, hand-pulling weeds will require more effort and time.
A herbicide application should kill the weeds, so they should not need pulling. Fertilise your lawn as the weeds start to die, this will allow the lawn to grow over and cover the dead weeds.
Make sure the weed killer has had time to work
One of the first mistakes that people make is trying to pull up the weeds before they've had time to properly absorb the weed killer. When the weeds have been sprayed, it can take a couple of days for the chemicals to be drawn down into the root of the plant.
This is exactly how I advise my customers. If it's a blanket spray then go ahead and mow before I come out because you will be putting the weeds back into an active growth cycle which will help metabolize the herbicide making it more effective and I'll be spraying everything anyway.
October isn't too late to spray for many weeds, especially perennial and winter annuals like clover and dandelion, as they actively store energy for winter, making fall applications highly effective for root control; however, effectiveness decreases with colder soil and frost, so aim for mild, dry days when weeds are still green and growing, but stop before deep freezes.
The best ways to kill weeds permanently include:
Most experts agree that the early morning or early evening hours are ideal. During these times, temperatures are cooler, wind speeds are lower, and many pests are either just becoming active or preparing to rest—making them more vulnerable to sprays.
Hand pulling is also one of the most environmentally friendly and cost efficient weed control methods. Make sure you remove the weed's entire root system when pulling them out of the ground; you can use a small-bladed knife to loosen the roots from the ground.
Weeds are not made to be easy to remove, that's for sure. They are made with taproots, rhizomes, or tubers that store energy underground so they can regrow. So if you pull a weed out by hand and leave even a small root fragment behind, that weed can sprout a new plant.
Post-Mowing and Herbicide Application:
The stressed weeds may also have a compromised ability to transport the herbicide throughout their system, reducing its efficacy. Therefore, post-mowing herbicide application is generally not recommended.
Weeds can spread rapidly if you don't pull them promptly. This can lead to them invading other parts of your garden, flower beds, or even your neighbor's yard. This rapid proliferation makes it even harder to control the weed population once it gets out of hand.
The solution: fill all ground with plants that you want, whether it's grass in a lawn, wall-to-wall shrubs and perennials in a border bed, or groundcovers under a tree. If you don't or can't fully plant, a second option is covering bare ground with mulch. 2.
Weed Killer Application Tips:
✅ Apply herbicides in the early morning (after dew dries) or late afternoon when temperatures are cooler and winds are calm. ❌ Avoid spraying during high heat or windy conditions to prevent drift and damage.
Autumn Spraying: September to October
Spray on mild, dry days when weeds are still growing. By late October, shorter days and colder soil temperatures slow plant activity, reducing herbicide effectiveness. Frosts can damage foliage, further limiting chemical uptake.
The hardest pests to get rid of often include bed bugs, cockroaches, termites, and rodents, due to their resilience, rapid breeding, ability to hide in tiny spaces, and resistance to common treatments, with bed bugs frequently cited as the toughest due to their elusive nature and insecticide resistance. Eliminating these pests usually requires professional help and persistent, integrated strategies like heat treatment, baiting, sanitation, and sealing entry points, notes.
For perennial weeds such as Plantain, Dandelion, Knotweed and Clover, apply a post-emergent herbicide in fall to send the killing chemicals directly to roots. This treatment will help reduce the numbers of these weeds in spring.
Mix one gallon of white vinegar with one cup of table salt and one tablespoon of liquid dish soap. This acts as a surfactant to help the solution adhere to the plant leaves while enhancing the vinegar's weed-killing properties.
To permanently stop weeds from growing, use a layered approach from Bunnings: first, remove existing weeds, then install a heavy-duty weed mat with no gaps, secure it, and cover with a thick layer (around 7cm) of mulch, and for persistent areas, consider using paver sand with polymeric sand or a long-term herbicide spray for paths, focusing on vigilant removal of any new growth before seeding.
Make sure the cut stem is positioned so the plant can absorb all the Roundup in the water-pick (Figure 2). To kill the entire plant, including the roots, remember to use this technique in the fall (August to late October) when the plant is moving sugars to the roots.
The best time to treat weeds is when they are actively growing. This means you should start spraying and treating in the spring, usually sometime in April. You'll have to maintain your weed-killing regiment into late September/early October. It's best not to jump the gun when using weed killers.
“Spray small weeds!” says Nagel. “It's all about weed size. You're really stepping off the ledge if you think you're going to control tough weeds more than 4 inches tall.” Nagel is an agronomist with Ceres Solutions.