The Best Weed Killer For Lawns
Let us help you choose the best lawn weed killer.
The Very Best “No Scorch” Lawn Weed Killers
Reviewed by the team at DIY Gardening in 2020
If you want a lawn to be proud of, at some point you’ll need to take action against invasive weeds.
Most lawn experts use targeted weed killers at least twice a year, this is usually sufficient to suppress weed growth, leaving space for the grass to thrive.
While there are hundreds of different species of weeds and invasive plants, most gardeners find using just two products is enough for treating lawns.
I should point out that products designed for use on hard surfaces and even flower beds should not be applied to lawns, at best they’ll scorch the grass, at worst, kill it.
The best lawn weed killers contain chemicals that mimic hormones, this causes the weed to grow uncontrollably until the growth cannot be sustained, the weed then dies.
The good news is that hormone-type weed killers are very effective against most broad-leaved weeds and do not persist in the soil for very long. Narrow leaves, such as grass blades, absorb very little of the chemical and can easily survive several doses per year.
The bad news is that hormone-type weed killers cause the weeds to grow like crazy at first and it takes time for them to wither and die. Apply these lawn weed killers outside of the growing season (spring and autumn) and it may take many weeks and several applications for the weeds to die.
For Small Gardens and Spot Treatments:
You only need two products if your garden is small and you’re able to spot treat the weeds with a handheld spray gun.
The two products listed below target broad-leafed weeds but they contain different chemicals.
If one type of weed is resistant to one of these products, there is a good chance it won’t be with the second one.
We recommend applying one product in the spring just as the growing season starts. The second product can be applied in late summer/early autumn.
Both of these lawn weed killers are the hormone-type, so expect the weeds to grow fast and tall before becoming twisted and deformed.
Resolva’s ready-to-use lawn weed killer spray contains two of the most effective chemicals available – Mecroprop-P and Dicamba. This combination is highly effective against daisies, dandelions, buttercups and plantain amongst many others. It can also control, to a lesser degree, thistles, ragwort, nettles and docks.
No dilution is required, you don’t even need to handle granules, powder or pellets either, just point the nozzle and spray. This product is perfect for lawn spot treatments and applications in small gardens. We recommend you apply this Resolva’s lawn weed killer during the springtime and a different product in the autumn.
Weedol’s ready-to-use lawn weed killer spray contains entirely different chemicals to those found in Resolva, all chemicals are of the hormone-type. Weedol contains MCPA, Clopyrlid and Fluroxypyr as the key ingredients. In addition to targeting common broad-leaved weeds, you’ll find that Weedol also treats an additional set of weeds.
Like Resolva’s product, no dilution is required, you don’t need to handle granules or pellets either, just point and spray. You can use Resolva anytime during the growing season but we suggest targeting as many weeds as possible by applying Resolva in the spring and Weedol late in the summer or early autumn.
For Larger Lawns:
For larger lawns, a ready-to-use handheld sprayer isn’t suitable. Instead, use either a granular lawn weed killer that can be washed in with a hose or apply a liquid-based variant that should be diluted and applied via a watering can or sprayer.
The two best lawn weed killers for larger areas are listed below.
As both contain different active ingredients, they should treat almost all known lawn weeds. Apply each product once per year, the first in the spring and the second in late summer or early autumn.
This version of Resolva is far more concentrated than the ready-to-use version. One small 500ml bottle treats approximately 250 square metres, for comparison; that’s 25 car parking spaces.
You’ll need to dilute this product with water and be extra careful; even the slightest miscalculation and you’ll scorch the grass. Failure to fully dilute correctly can also lead to lawn damage. Resolva concentrate is a professional grade product and you get far more bang for your buck compared to ready-to-use products.
To treat as many different weeds as possible, we suggest applying Resolva in the spring and another product with different chemicals in the autumn.
Weedol’s concentrated version comes in a 250ml bottle and once diluted will produce enough lawn weed killer to treat 165 square metres. As with Resolva’s equivalent product, it contains hormone-type chemicals that cause the weeds to grow uncontrollably until the cells within the weed collapse and the plant withers and dies.
As this product contains different hormone-type chemicals, it will target a slightly different set of weeds than Resolva’s product.
For medium and large lawns, we suggest you apply Resolva concentrate in the spring and Weedol concentrate in late summer or early autumn. This increases the number of weeds that will respond to the chemicals.
To Remove and Prevent Lawn Moss:
None of the lawn weed killer products listed above are effective against moss.
For effective lawn moss removal and prevention, there are only two products we think you should choose from.
By getting rid of lawn moss, your grass will be given the space to grow and thrive. A thick lawn will suppress many common weeds as they won’t be given the space and sunlight needed to flourish.
Targeted lawn weed killers won’t kill lawn moss but there are several “all in one” products that contain iron sulphate, which works well at controlling moss growth in lawns.
You can use iron sulphate as a standalone treatment or consider an organic bacteria-based product such as MO Bacter:
Iron Sulphate Powder
Iron sulphate is one of the most popular products used by gardeners to green lawns that are lacking colour or are browning due to excess sunlight and heat.
At a higher concentration, usually double the normal dose, iron sulphate acts as a moss killer.
Formulated as a powder, you’ll find this product is easy to dilute but extra care should be taken not to spill the liquid onto concrete, patios or timber decking as it may stain the surface.
When applied to lawns, do make sure the ground is damp and stays damp for a few days after application. If the surface is allowed to dry, the grass may scorch.
We’ve found that the best time to apply iron sulphate at higher doses is in late March or April after the last winter frosts but before the hot, dry season.
You can expect the lawn moss to turn black within a week or so, you’ll then need to rake out the dead matter and overseed the bare patches with your preferred grass seed.
“No Rake” Moss Killer
Traditional moss killer products burn and kill the moss, you then need to rake or scarify the lawn.
For large lawns, this process is time-consuming and often not practical.
As an alternative, try a product that contains specially created bacteria that consumes the moss while leaving the grass blades and roots untouched.
This is our favourite but there are several other brands that are very similar.
The process is slow but requires very little effort and as the bacteria gradually breaks down the moss, you can then overseed to encourage the grass to grow in the space created.
We’ve found that the bacteria approach often requires a couple of doses but it remains our preferred method as children and pets can still use the lawn and there’s no risk of damaging patios, decking or plants etc.
If you’re trying to minimise the number of chemicals you use in your garden, try this product for lawn moss control.
If your lawn is carpeted in moss, check out our detailed 8-step guide to removing and preventing lawn moss.
All-In-One Lawn Weed and Feed Products
All-in-one lawn products often contain the following:
- Iron Sulphate – this is a double-action chemical as it kills moss and also turns the grass bright green.
- Lawn weed killers such as Mecoprop-P and MCPA which are effective on around 90% of broad-leaved weeds.
- Fertilisers for root and stem growth (N,P,K).
All-in-one products aren’t always the best option and you may find the moss treatment (iron sulphate) or the weed killer chemicals to be too weak.
We suggest you use all-in-one products to maintain a lawn that is already in good condition.
Use specific lawn weed killers and moss treatment products for a more targeted and aggressive approach.
Below you’ll find the best all-in-one lawn weed and feed products. As they contain different weed killer chemicals we suggest you purchase both and use one in Spring and one in late summer/early Autumn. This increases the number of weeds that will be treated.
Westland All-in-One Aftercut
Westland Aftercut is an all-in-one product that contains iron sulphate to green up the lawn and kill the moss while added fertilisers encourage root and blade growth.
The mixture is complimented by the inclusion of three hormone-type weed killers; 2,4-Dichlorophenoxyacetic acid, Mecoprop-P and Dicamba. These three chemicals will kill almost all known broad-leaved lawn weeds without harming the grass.
Apply this product once a year in the spring or autumn, a second yearly application is usually only needed for heavily infested lawns.
The granules in this product can be spread directly onto the lawn by hand and then watered in with a hose. You’ll need to rake out any dead moss after around 14 days and then overseed any bare patches. We suggest applying this product in spring or autumn.
Miracle-Gro Evergreen Complete
Containing a healthy balance of fertilisers, iron sulphate and two hormone-type weed killers, this all-in-one lawn feed and weed is a popular choice amongst gardeners.
MCPA and Mecoprop-P are two effective weed killers that treat around 90% of known broad-leaved lawn weeds.
As with other granular lawn weed and feed products, it contains a well-balanced mixture of fertiliser (NPK). This encourages blade growth, root depth and improves disease resistance.
The iron sulphate kills moss and turns the grass a lush green colour.
We recommend all-in-one products to maintain healthy lawns. If your lawn is heavily infested with moss or weeds, we suggest a more aggressive product that’s designed specifically for that task.
Other Lawn Care Products We Think You’ll Like
By improving the quality, density and resilience of your lawn, weeds will be suppressed and less likely to thrive. You can then use fewer chemicals during your maintenance schedule.
Weed Removal Tool
If you have a small lawn, you’ll find this to be the best tool for pulling out weeds. The fulcrum handle creates leverage so you can easily remove deep-rooted weeds in lawns and flower beds. Rustproofed and with a soft handle, this tool is built to last.
This tool works on thistles and dandelions as well as many other common weeds.
Shade Tolerant Seeds
Dense healthy grass will crowd out lawn weeds but if you have a shaded garden, the lawn may be sparse and patchy, this creats plenty of space for weeds to thrive. Use shade tolerant grass and you’ll be on your way to preventing lawn weeds from growing.
Graminex contains six different shade tolerant grass seed, guaranteeing germination.
Lawn Aeration Shoes
Advertised as a cheap and easy way to aerate the soil under the lawn, these shoes have mixed reviews on Amazon and other online retailers, so we tested them. Lawn aeration is a great way to loosen up a compacted ground, but do lawn shoes work?
Head over to our blog and see what we think of lawn shoes and a few alternatives.
Our Favourite Mower
This is our favourite mower for large areas; it’s petrol-powered, comes with a mulching bag and most importantly has six cutting heights from 2.5cm up to 7.5cm. If you have lots of weeds in your lawn, letting it grow tall can help to suppress them.
This self-propelled petrol mower makes cutting grass to any height easy with reduced effort.
Lawn Weed Tool
This is by far the most reliable and efficient lawn weed removal tool we’ve tested, it pulls out not just the weed and leaves but also the root too. There’s no need to bend over with this product, remove weeds from lawns and flower beds with ease whilst standing up.
We managed to remove over 100 thistles and dandelions in one hour.
General Lawn Fertiliser
Westland’s Growmore Garden Fertiliser is a general purpose fertiliser with 7% Nitrogen, 7% Phosphorous and 7% Potassium. This product is perfect for preparing the soil near tree and plant roots where there is competition for both water and nutrients.
Supply your lawn with the nutrients it needs and weeds will be crowded out.
The lawn Guide Book
Our favourite book: The Lawn Guide by Sharples and Hayman is a great read, learn how to prepare a garden for laying turf or seed. Where this book truly excels is in its lawn maintenance advice and tips such as how to deal with lawn weeds.
Want to know how to grown the perfect lawn in any condition? This is the the book for you.
Perfect for removing moss and dethatching lawns, this specialist garden rake frees up space for your grass to grow and thrive. With more horizontal grass spread, you’ll see fewer weeds growing. Use this rake on thick dense lawns suffering from excess moss.
This metal scarifier is designed specifically for removing moss and dead thatch.
Lawn Weed Killer FAQs
Can Lawn Weed Killers be Used on New Lawns?
Most broad weed killers can be applied to a freshly seeded or turfed lawn after around 6 months. Targeted weed killers can often be used after 3 months but you should spot test the product first.
How Many Times a Year Can a Weed Killer be Applied?
Most granular or concentrated liquid weed killers can be applied twice a year, the first application should be at the start of the growing season in the spring. The second application should be in early autumn. There’s no need to apply lawn weed killers in late autumn or winter as weed growth is limited at this time.
How Long After Applying a Lawn Weed Killer Can Pets and Children be Allowed Onto the Lawn?
In most cases, pets and children can be allowed onto the lawn after 24 hours or after the product has dried, whichever is the longest.
Do Lawn Weed Killers Also Treat Moss?
No, most targeted lawn weed killers do not have any effect on moss. Some, such as “all in one” products may contain Iron Sulphate which turns the grass bright green and also kills light lawn moss. These products are rarely effective against lawns suffering from severe moss infestations.
Can I Remove Lawn Moss Without Using Chemicals?
Yes, garden rakes and scarifiers can remove the moss and dethatch the lawn ready for an overseeding with lawn seed. Organic moss treatment products can also be used, these contain bacteria which eat away at the moss whilst leaving the grass unaffected.
Explore More of Our Lawn Care Guides Below:
All LAWN CARE GUIDES
Discover all of our lawn care guides published here at DIY gardening. Learn how to grow grass in shady gardens and how to remove and prevent pervasive weeds and moss. Start Here
HOW TO GROW GRASS IN SHADED GARDENS
Read our in-depth 10-step guide to successfully growing a dense and green lawn in shaded gardens – where grass often struggles to grow. Start Here