How To Apply Lawn Weed Killer
Keep Your Lawn Healthy While Removing Unwanted Weeds , learn how to apply lawn weed killer correctly, including when to spray, how to prepare your lawn, application tips and common mistakes to avoid.
At Elixir Garden Supplies we believe that a healthy lawn can completely transform the appearance of your garden, but weeds can quickly spoil its appearance by competing with grass for sunlight, water and nutrients.
The good news is that most common broadleaf lawn weeds can be controlled successfully when the correct product is applied at the right time.
 Left untreated, common lawn weeds such as dandelions, clover, daisies and plantain can spread rapidly, weakening your lawn and making it more difficult for healthy grass to thrive.
Applying a selective lawn weed killer like Hytrol is one of the most effective ways to control broadleaf weeds without damaging established grass.
 However, the timing, preparation and correct application technique all play a crucial role in achieving the best results.
Recommended Product
For this guide, we’re using Hytrol Selective Lawn Weedkiller Concentrate, a professional-quality selective herbicide designed to control a wide range of common broadleaf weeds while leaving established grass unaffected when used according to the product label.
In This Guide
In this guide, our Elixir Gardens experts will explain everything you need to know about applying lawn weed killer, including:Â
- when to treat your lawn
- how to prepare the area
- the correct application technique
- common mistakes to avoid
- how to achieve the best results
Why Do Weeds Grow in Lawns?
Before treating weeds, it’s important to understand why they appear in the first place.
Weeds often take advantage of weak or stressed lawns where grass isn’t growing densely enough to outcompete them.
Some of the most common causes include:
- Thin or patchy grass
- Compacted soil that restricts root growth
- Poor drainage
- Nutrient deficiencies
- Excessive shade
- Irregular mowing
- Bare patches caused by pets or heavy foot traffic
While lawn weed killer removes existing weeds, improving the overall health of your lawn with a reliable fertliser such as Spring & Summer 12-3-9 is the best long-term defense against future weed problems.
Identify the Weeds in Your Lawn
Common Broadleaf Lawn Weeds
Different weeds require different approaches, so identifying what’s growing in your lawn is the first step towards successful treatment.
Dandelions
One of the UK’s most recognisable lawn weeds, dandelions have bright yellow flowers and long taproots that make them difficult to remove by hand.
White Clover
Clover spreads quickly across lawns and is easily recognised by its three-part leaves and white flowers.
Daisy
Although attractive to some gardeners, daisies compete with grass and spread rapidly in neglected lawns.
Plantain
Plantain produces large, flat leaves that sit close to the soil surface and are resistant to regular mowing.
Buttercup
Often found in damp lawns, buttercups can quickly spread where drainage is poor.
Correctly identifying weeds helps ensure you’re using the right treatment and applying it at the best time.
Choose the Right Lawn Weed Killer
Not all weed killers are designed for lawns.
Selective Weed Killers
Selective weed killers like Hytrol target broadleaf weeds while leaving established grass unaffected when used correctly.
These are ideal for:
- Family lawns
- Ornamental lawns
- Recreational grass areas
Total Weed Killers
Non-selective weed killers like Glyphosate Weedkiller kill almost all vegetation they encounter and should never be sprayed across a healthy lawn.
They’re best suited for:
- Paths
- Driveways
- Patios
- Fence lines
If your goal is to remove weeds without killing your grass, always choose a selective lawn weed killer.
When Should You Apply Lawn Weed Killer?
Applying lawn weed killer at the right time of year significantly improves results.
The best time to apply is during periods of active weed growth, typically between spring and early autumn.
Ideal Conditions
- Mild temperatures
- Dry weather
- Little or no wind
- Healthy, actively growing weeds
Avoid applying during:
- Frost
- Heatwaves
- Drought
- Heavy rain
- Strong winds
Weather conditions directly influence how effectively weeds absorb treatment.
One question we’re regularly asked is whether it’s worth spraying weeds during colder weather. In our experience, treatments are generally far more effective when weeds are actively growing, allowing the product to move throughout the plant more efficiently.
Prepare Your Lawn
Preparation ensures maximum contact between the weed killer and the weeds.
Before spraying:
- Remove leaves and garden debris
- Mow the lawn several days before treatment
- Avoid mowing immediately before spraying
- Ensure weeds have plenty of healthy leaf growth
- Check the weather forecast
Avoid treating newly seeded or recently laid lawns unless the product instructions specifically state otherwise.
We’ve also found that customers often achieve better results when they spend a few minutes preparing the lawn before spraying. Removing debris and ensuring weeds have healthy leaf growth gives the product the best chance of making good contact with the plant.
Apply the Weed Killer Correctly
Always read the product label before mixing or applying any lawn weed killer.
When using Hytrol Selective Lawn Weedkiller Concentrate, follow the manufacturer’s recommended dilution rates, coverage and safety guidance.
Application Tips
- Measure accurately
- Use clean equipment
- Spray evenly across affected areas
- Avoid overlapping passes
- Prevent spray drift onto flowers, shrubs and vegetable beds
Walking at a consistent pace while maintaining an even spray pattern helps achieve uniform coverage.
What Happens After Application?
Once applied, the active ingredients are absorbed through the leaves and transported throughout the weed.
Visible symptoms usually develop gradually and may include:
- Curling leaves
- Yellowing
- Twisting stems
- Slowed growth
- Dieback
Resist the temptation to reapply too quickly.
Many selective weed killers require time to move through the entire plant.
Healthy grass is your best natural defence against weeds. A thick, well-maintained lawn naturally shades the soil, making it more difficult for new weed seeds to germinate and establish.
Common Mistakes to Avoid
Many lawn weed treatments fail because of avoidable mistakes.
Avoid:
- Spraying during windy weather
- Applying before heavy rain
- Using too much product
- Treating drought-stressed lawns
- Mowing immediately before or after treatment
- Using total weed killer on lawns
- Ignoring the underlying cause of weed growth
Following the product instructions and maintaining a healthy lawn will improve long-term results.
Hytrol Selective Lawn Weedkiller Concentrate
Best for:Â
- Established lawns Â
- Broadleaf weeds
- Routine lawn maintenance Â
Why choose this product?Â
If your lawn contains broadleaf weeds but you want to keep the grass, we believe a selective lawn weed killer is the correct choice. Â
Hytrol is formulated to target many common broadleaf weeds while allowing established grass to continue growing when used according to the product instructions. This makes it ideal for homeowners looking to improve the appearance of their lawn without having to reseed the entire area.Â
Recommended when:Â
- Your lawn is otherwise healthy
- Broadleaf weeds are spreading
- You want to preserve existing grass
Ready-to-Use Hytrol Selective lawn Weed Killer
Best for:
- Small gardens
- Spot treatments
- Occasional maintenance
- Homeowners who prefer not to mix concentrates
Why choose this product?
Ready-to-use Hytrol is intended for spot treatment of broadleaf weeds growing within established lawns. It offers the convenience of a pre-mixed formulation while helping preserve surrounding grass when applied according to the label.
Recommended when:
- Weeds are growing within established grass
- Only a small lawn area needs treatment
- The customer does not want to measure or dilute concentrate
Read More...
- How to Remove Dead Weeds From Your Lawn
- How to Repair a Lawn After Weed Treatment
- Identifying Lawn Weeds
- Best Weed Killer Guide
- How to Safely Use Weed Killer Around Pets and Children
- How Long After Using Weed Killer Can I Seed My Lawn?
- When Is Lawn Weed Killer Most Effective?
- Glyphosate vs Selective Weed Killer
Frequently Asked Questions
Will lawn weed killer kill my grass?
The moss usually begins darkening within a few days, although timing depends on weather conditions and the product used.
How long does lawn weed killer take to work?
Always follow the instructions on your chosen product, as application advice can vary between formulations.
Can I mow after applying lawn weed killer?
When used according to the manufacturer’s instructions, it is designed for use on established lawns. Over-application or misuse may damage the grass or stain surrounding surfaces.
Can I apply lawn weed killer before rain?
Yes. Dead moss should be raked or scarified away to allow healthy grass to recover.
Can I overseed after applying weed killer?
No. It kills existing moss, but long-term prevention depends on improving lawn health through feeding, aeration, drainage and overseeding.
How often should I apply lawn weed killer?
Use Weedkillers Safely
Always follow the product label and manufacturer’s instructions before use. Different weed killers have different application methods, timings and safety requirements, so reading the label carefully helps ensure effective results and safe application.Â
Wear Appropriate PPE
When handling concentrates or applying weed killers, wear suitable personal protective equipment (PPE) as recommended on the product label. This may include gloves, eye protection or protective clothing to minimise unnecessary exposure.
Application Rates
Applying more weed killer than recommended won’t improve performance and may increase the risk of damage to surrounding plants or the environment. Always measure accurately and apply at the recommended rate for the best results.
Rhys Nield
As one of our resident product experts, Rhys has spent the last 2 years helping keen gardeners and growers from within our customer services department. Remember to save this page, or visit the Advice Centre, for the latest tips, articles, and expert knowledge, to help you make your garden the best it can be.
1L 360g/l Glyphosate Weedkiller | Super Strength Root-Killing Concentrate
£20.83 £184.24Price range: £24.99£20.83 through £221.09£184.24 incl. VATex. VAT
4L Glyphosate Root-Killing Weed Killer with Spray Head Attachment | 7.2g/l Ready-to-Use Solution
£15.74 £146.88Price range: £18.89£15.74 through £176.25£146.88 incl. VATex. VAT
4L Hytrol Selective Lawn Weedkiller | Ready-to-Use Solution
£14.99 £139.99Price range: £17.99£14.99 through £167.99£139.99 incl. VATex. VAT
500ml Concentrate Hytrol Selective Lawn Weedkiller
Original price was: £16.49£13.74.£13.19£10.99Current price is: £13.19£10.99. incl. VATex. VAT
4L Fast-Acting Weed & Moss Killer | Glyphosate-Free Ready-to-Use Formula
£15.74 £158.13Price range: £18.89£15.74 through £189.75£158.13 incl. VATex. VAT
About Elixir Gardens Supplies
For over 35 years Elixir Garden Supplies have been providing gardeners with all the essentials they need to achieve growing.
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