Weed and feed products are one of the most heavily marketed lawn care products in Australian hardware stores. The pitch is straightforward: one product handles both your weed problem and your fertilising in a single application. Less time, less effort, fewer products to buy.
It's a compelling idea. But on Perth's sandy soils, in our warm climate, and with the turf varieties grown here, the reality is that weed and feed rarely delivers the results that two separate, purpose-built products would. In most cases you end up with a compromise on both the weed control and the fertiliser — neither done as well as it should be.
Here's why, and what to use instead.
The Short Answer
Weed and feed products require both the weeds and the lawn to be in exactly the right condition at the same time — which almost never happens on Perth lawns. A dedicated broadleaf herbicide targets actively growing weeds at the right concentration. A dedicated fertiliser feeds the lawn at the right rate for the season. Using both separately takes an extra 20 minutes and produces significantly better results in both areas.
What weed and feed actually is
Weed and feed is a granular product that combines a herbicide — usually targeting broadleaf weeds — with a granular fertiliser. The idea is that you spread the granules across the lawn, the herbicide kills the weeds and the fertiliser feeds the grass simultaneously.
The problem is that these two jobs have fundamentally different requirements in terms of timing, application rates, soil moisture and temperature. Bundling them into a single application means accepting a compromise on both. And on Perth's sandy, free-draining soils and in our warm, variable spring climate, those compromises matter more than they would in cooler, more uniform conditions.
Five reasons to use separate products on Perth lawns
Reason 01
The timing requirements are completely different
A broadleaf herbicide works best applied to actively growing weeds in mild temperatures — typically between 15 and 25 degrees. Applied in heat, it volatilises before it can be absorbed. Applied to dormant weeds, it has nothing to work on. Perth's spring transitions through this range quickly, and the optimal herbicide window is often narrow.
Granular fertiliser, on the other hand, needs to be applied when soil temperatures are warm enough for the grass to take up nutrients — generally above 15 degrees. But the timing, rate and formulation of the ideal spring feed has nothing to do with whether broadleaf weeds are present. When you combine them into a single product, you are applying both according to one timing decision — which means at least one of them is being applied at a suboptimal time.
Reason 02
Perth's sandy soils leach nutrients faster than the herbicide can work
This is the critical Perth-specific problem. Our coastal sandy soils drain exceptionally fast. The granular fertiliser component of a weed and feed product needs to be watered in to activate — but the herbicide component in most granular weed and feed products is designed to stay on the leaf surface and be absorbed through the foliage, which means watering immediately after application washes it off.
This creates an impossible situation: if you water in to activate the fertiliser, you reduce the herbicide's effectiveness. If you don't water in, the fertiliser leaches through before the roots can absorb it, or just sits on the surface in Perth's heat. Either way, one of the two jobs is being done poorly.
Reason 03
You cannot control the application rate of each independently
When you apply a weed and feed, the herbicide rate is locked to the fertiliser rate. If your lawn needs a heavy spring feed — which Perth lawns often do after winter — increasing the spread rate also increases the herbicide concentration, which risks burning the lawn or damaging turf in areas without weed coverage. If you want a light, maintenance feed, you're also reducing the herbicide rate below what's needed for effective weed control.
With separate products, you spread your fertiliser at the rate your lawn needs and apply your herbicide at the rate the weeds need. Two independent decisions, both made correctly.
Reason 04
Broadleaf herbicides need to be targeted — not broadcast across the whole lawn
Most Perth lawns don't have broadleaf weeds distributed evenly across every square metre. Weeds cluster in areas — edges, stressed patches, shaded sections or spots where the turf is thin. Applying a weed and feed across the entire lawn means you're spreading herbicide over areas that don't have weeds, and potentially still under-treating the patches that do.
A selective post-emergent broadleaf herbicide applied through a sprayer or hand bottle puts product exactly where the weeds are, at the right concentration, without affecting the rest of the lawn. It's more targeted, more effective and uses less product overall.
Reason 05
Buffalo-safe compatibility is non-negotiable in Perth
Sir Walter Buffalo is the most popular turf variety in Perth by a significant margin — and buffalo grass is sensitive to many of the herbicide actives commonly used in weed and feed formulations, particularly those containing dicamba, MCPA or bromoxynil. Applying the wrong weed and feed to a Sir Walter lawn can cause serious damage — yellowing, leaf burn and in severe cases, long-term injury to the turf.
With a dedicated broadleaf herbicide, you choose a product that is specifically labelled as safe for your variety. Dedicated herbicides for buffalo turf are well established, widely available and clearly labelled. A weed and feed product that has blanket compatibility claims should always be treated with caution on buffalo lawns.
The comparison at a glance
| Factor |
Weed and Feed |
Separate Herbicide + Fertiliser |
| Timing flexibility |
✗ Both applied at once — one is usually suboptimal |
✓ Each applied at the right time for its job |
| Application rate control |
✗ Herbicide rate locked to fertiliser rate |
✓ Each applied at the correct independent rate |
| Perth sandy soil performance |
✗ Watering conflict between herbicide and fertiliser activation |
✓ Each product managed to its own watering requirement |
| Targeting accuracy |
✗ Broadcast across the whole lawn regardless of weed location |
✓ Herbicide applied only where weeds are present |
| Buffalo compatibility |
✗ Many formulations risk damaging buffalo turf |
✓ Buffalo-safe herbicides clearly labelled and available |
| Weed control effectiveness |
✗ Diluted concentration, imprecise application |
✓ Full concentration at correct rate for the target weed |
| Fertiliser effectiveness |
✗ Rate and timing compromised by herbicide component |
✓ Chosen and applied for exactly what the lawn needs |
⚠️
If you do use weed and feed
Always check the label for compatibility with your turf variety before applying — particularly for Sir Walter Buffalo. Apply when weeds are actively growing and temperatures are between 15 and 25 degrees. Do not apply in heat above 30 degrees. Do not apply to drought-stressed or recently mowed turf. Water in according to the specific product's label instructions, not a general rule.
What to use instead
The better approach for Perth lawns is straightforward: identify what you need to treat, choose a dedicated herbicide for the specific weed problem and apply it independently from your fertilising program. Then apply your fertiliser at the right rate for the season with the right formulation for your soil and variety.
For spring in Perth, the two most common weed targets are broadleaf weeds — bindii, clover, capeweed, dandelion and creeping oxalis — and grass weeds like wintergrass and summer grass. These require different products and different timing, which is another reason a generic weed and feed rarely addresses both effectively.
Broadleaf Herbicides
Pre-Emergent + Feed
OxaFert
A granular pre-emergent herbicide and fertiliser combined — but unlike a typical weed and feed, OxaFert is specifically formulated so both components activate under the same conditions. Stops oxalis, wintergrass and crowsfoot before they germinate. Applied in May or early September for best results.
Shop OxaFert
Liquid Pre-Emergent
Barricade
Liquid pre-emergent herbicide applied through a sprayer. More effective penetration than granular in dense or thatchy turf. Targets crabgrass, summer grass, wintergrass and poa annua. Apply in September ahead of summer weed germination.
Shop Barricade
Fertilisers
Granular Fertiliser
Knights Coastal Special Mix
Formulated specifically for Perth's coastal sandy soils. Balanced nitrogen, potassium and trace elements applied at a rate suited to the season — independent of whatever weed treatment you're running. Apply and water in immediately. Suitable for all varieties.
Shop Knights
Liquid Fertiliser
Exceed Liquid Fertiliser
Fast foliar uptake applied as a spray to the leaf blade — completely independent of soil moisture conditions. Ideal as a follow-up feed two to three weeks after a granular application. Works even when the soil is too dry for granular nutrient uptake.
Shop Exceed
💡
The Practical Spring Program
Week 1: Apply Barricade or OxaFert pre-emergent to stop summer weed germination. Water in as directed.
Week 2: Apply Knights Coastal Mix at the recommended spring rate. Water in immediately and thoroughly.
Week 3-4: Spot spray any visible broadleaf weeds with a dedicated selective post-emergent herbicide labelled for your turf variety.
Week 4-5: Apply Exceed liquid fertiliser as a foliar top-up to sustain colour and push growth through peak spring.
🌱 Coming Soon to Lawn Doctor
Stampede Hybrid
Buffalo.
We are growing something exciting at our Swan Valley display farm. Stampede Hybrid Buffalo is Australia's newest and most advanced buffalo grass variety — the result of six years of trials in Australia and the United States, developed through advanced hybrid breeding technology by Texas A&M University and brought to market by Lawn Solutions Australia.
Stampede is not an incremental improvement on existing buffalo varieties. It is a genuinely different plant — an interploid hybrid that outperformed every other buffalo cultivar in field trials across multiple sites and conditions. For Perth homeowners, the combination of improved winter colour, outstanding drought tolerance and high shade tolerance makes it the most well-rounded buffalo option we have seen come to market.
Improved winter colour retention — stays green longer through Perth winters than standard buffalo varieties
Outstanding drought tolerance — selected for its ability to maintain quality under heat and water stress
Excellent shade tolerance — rated above 75%, performing well in sites with limited direct sun
Strong wear recovery — fast lateral spread and vigorous regrowth after damage
Improved disease resistance — showed no disease signs during humid summer trials where other buffalo varieties were affected
AusGAP certified — genetically verified for purity and consistency
We are currently preparing our Swan Valley display farm for Stampede — the photos above show the preparation underway. We will be among the first suppliers in Western Australia to offer this variety when stock becomes available.
📍 Stampede Hybrid Buffalo display farm — Swan Valley, Western Australia. Currently in preparation. Available to enquire now — contact us to register your interest.
Get the right products for your lawn
Shop dedicated herbicides
and fertilisers online.
All products available with delivery across Perth, or come in to our Wangara showroom for advice. Our team can help you work out the right treatment program for your variety and weed situation.
