Every spring the same thing happens. You put your pre-emergent down on the date you did it last year, and summer grass turns up anyway. The problem is almost never the product. It is the timing. Weed seeds do not go by the calendar, and neither should you.
The short version
- A pre-emergent stops weed seeds before they sprout. It will not kill weeds that are already up.
- Time it to the season, not a set date. Get it down in early spring, before summer grass, crowsfoot and crab grass come through.
- Barricade HG gives up to six months of control from a single application.
- Water it in lightly to activate the barrier, and keep it off any lawn you have just laid or seeded.
- Pair it with grub protection, a soil wetter and a feed for a full spring set-up.
What a pre-emergent actually does (and what it can't)
A pre-emergent does not kill the weeds you can see. It works underground. It lays a thin barrier through the top layer of soil that stops weed seeds developing as they try to germinate. Barricade HG binds to the top 1 to 2 cm of soil and holds there, so summer weeds like summer grass, crab grass and crowsfoot never get established.
The catch is simple. If a weed is already up and growing, a pre-emergent will not touch it. Those ones need a post-emergent treatment instead. So the whole job comes down to one thing: getting the barrier down before the seeds wake up.
Why the calendar is the wrong way to time it
Weed seeds respond to the soil warming as winter lets go, and that shifts from year to year and even from suburb to suburb. A fixed date cannot keep up with that.
Go too early and the barrier can thin out before the seeds germinate. Go too late and the weeds are already through, past the point a pre-emergent can help. Timing to the season beats timing to a date every time.
When to put Barricade HG down
Put it down in early spring, as the days start to warm and before last summer's weeds reappear. Your own lawn is the best guide. If summer grass or crowsfoot took hold through the warm months last year, the time to stop them is now, while the ground is still clear.
One application of Barricade HG lasts up to six months, so a single early-spring pass covers you right across the weed season. If you have left it late and weeds are already showing, deal with those first, then lay the barrier for the next flush. Always read the full product label before you start, and you can confirm the registration on the APVMA public register.
How to apply it, step by step
- Mow and clear. Mow a few days beforehand and clear off leaves and debris so the product reaches the soil.
- Prep the soil to take up water evenly. If your lawn sheds water or dries out in patches, a soil wetter like AquaSport helps moisture, and the barrier, spread evenly instead of running off. More on that in our guide to wetting agents versus water crystals.
- Measure your lawn and your rate. Use our application rate calculator so you mix the right amount for your area, with no guesswork.
- Apply evenly. Spread Barricade HG evenly across the lawn, keeping your pace steady so you do not double up or miss strips.
- Water it in lightly. Around 3 mm of watering activates the barrier and locks it into the top of the soil. Do not drench it.
- Leave it be. Avoid heavy raking or digging that breaks the barrier, and feed a few days later rather than at the same time.
One thing to note: do not blend Barricade with granular fertiliser or any other granular product. Apply each on its own.
Finish the job: grubs, water and feed
Weeds are only half the spring story. The same early-spring window is the time to get ahead of lawn grubs and armyworm, before they hatch and start chewing through the roots.
Acelepryn GR gives up to six months of grub protection from one application, spread on with a standard fertiliser spreader. It is the home version of the product professionals rate, so you get the same result without the guesswork. Our guide on stopping lawn grubs, curl grubs and armyworm walks through the timing.
Round it out with a soil wetter so the lawn drinks properly through the heat, and a feed such as Lawn Builder All Purpose a few days after the pre-emergent to push healthy growth. Do all of this in the same fortnight and your lawn heads into summer set up to win. If you want to stay ahead of the heat, our summer survival guide and our piece on liquid seaweed for lawns pick up where this leaves off.
Can you use it on a new or patchy lawn?
Not on fresh lawn. Barricade HG stops seeds germinating, and that includes lawn seed, so keep it off anywhere you have recently seeded, laid, or plan to over-sow. On newly laid turf, wait until it is fully established and rooted in before you apply.
It is also best kept off a lawn that is stressed or struggling. Get the lawn healthy first, then protect it. On an established, healthy lawn of couch, buffalo, kikuyu or zoysia it is right at home, though it is always worth checking the label for your particular lawn type.
Shop Barricade HG and get your barrier down before the weeds come up.
Frequently asked questions
When should I apply pre-emergent in Australia?
Apply it in early spring, as the weather warms and before summer weeds like summer grass and crowsfoot come up. Time it to the season turning rather than a set date, because the soil warms at different times each year and in different areas.
Will pre-emergent kill the weeds I already have?
No. A pre-emergent stops weed seeds from developing as they germinate. It has no effect on weeds already up and growing, which need a post-emergent treatment instead.
How long does Barricade HG last?
Up to six months from a single application, so one early-spring pass covers the whole summer weed season.
Can I apply it to a new lawn?
No. It stops lawn seed germinating too, so keep it off anywhere recently seeded, laid or due to be over-sown, and wait until new turf is fully established.
Can I fertilise at the same time?
Apply your pre-emergent first and water it in, then feed a few days later. Do not blend Barricade with granular fertiliser or other granular products. Apply each on its own.
Get your barrier down before the warm weather brings the weeds up, and you will spend summer enjoying the lawn instead of fighting it. Let's Grow!