The best weed killer is a vital aid for any gardener who wants to keep their outside space spick and span. Whether it's tackling dandelions pushing up your patio paving, getting moss out of your lawn mower's way, or dealing with bindweed strangling your bedding plants, it's a battle we all face.
While you can use garden tools like hoes to dig out established perennial weeds, a decent weed killer can make dealing with all these problems a lot easier, saving you some serious manual labour when it comes to weed removal. This is because weed killer does just as its name suggests, leaving you to remove dead growth rather than wrestle with healthy plants.
Best weed killers at a glance:
• Best overall weed killer: Roundup Naturals Glyphosate-Free Powerful Weed Killer - View on Amazon UK
• Best for lawns: Greenforce Lawn Weed Killer - View on Amazon UK
• Best for hard surfaces: Flow Super Strength Garden Acetic Acid - View on Amazon UK
While we want the weeds gone, we want to do this in the most eco-friendly way possible to avoid harming the wider garden ecosystem. After all, most weeds are just wildflowers, growing in the ‘wrong’ place. The best way to achieve this is to avoid using chemical weed killers and instead focus your attention on more 'organic' weed killers that don't contain butterfly- and bee-harming glyphosate. Some weed killers are also based on naturally occurring active ingredients such as fatty acids, acetic acid and pelargonic acid, which come from pelargonium plants.
We're taking a look at the best weed killers you can feel confident using knowing they keep your garden - and the birds and the bees - happy and healthy.
Best weed killers for your garden
Best overall
Roundup/AmazonThis ready-to-use formula from Roundup is a convenient option to have to hand for general weed control in your outside spaces. It comes in a one-litre bottle and has a child-safe spray nozzle for easy application. This weed killer can tackle clover, chickweed, and common groundsel, among other pesky plants, and can show visible results in as little as three hours.
Customer review: "Easy to control flow rate for good economical coverage. Some weeds died within a few hours but most took over night to show excellent results. Well worth the price for a product that really works."
Pros
- Bottle made from 34% recycled plastics
- Does not require diluting
Cons
- Trigger is not recyclable
Best organic weed killer
Weedkil/Amazon This is another option that's ready to go out of the box giving you an organic, safe, and glyphosate-free solution. This can be used all year round, but it's recommended to use it in dry weather. Once dried, which takes around 20 minutes, this is totally child- and pet-safe. This multi-purpose weed killer can be used on hard surfaces, lawns, and even in flower beds.
Customer review: "Strong weed killer - very effective and I like the fact it is harmless to dogs. Good value."
Pros
- Safe for kids and pets
- Contains acetic acid
Cons
- Not recommended for weeds more than 10cm tall
Best weed killer for lawns
Greenforce/AmazonThis clever solution from Greenforce will help you get a pristine, weed-free lawn. It kills common broad-leaved weeds such as docks, daisies, dandelions, buttercups, clover, nettles, and soft thistle - but it won't kill your lawn grass. This can be applied with a garden sprayer or via a watering can, although we'd advise using a different can than you do to water your plants.
Customer review: "Easy to use! Required for very large lawn, used 15 litre sprayer at the required mix. Results started to appear within three days, very impressive, had all sorts of weed in the lawn, docking, clover, dandilion, daisy, buttercup to name a few. Two weeks after spraying, most weeds now in retreat appart from the odd one I probably missed with the sprayer."
Pros
- Won't kill grass
- Covers 500 square metres
Cons
- Requires dilution
Best weed killer to tackle roots
Neudorff/AmazonIt's one thing offing a few buttercups with a standard spray, but for more stubborn weeds like dandelions, thistles, and crabgrass you need a weed killer that will get to the roots. This concentrate from Neudorff tackles weeds from the root up, working within hours. Once applied this promises long-lasting results to rid your garden of even the toughest weeds.
Customer review: "Strong and immediate. Great product that does a good job of clearing stubborn weeds."
Pros
- Certified for organic gardening
- Long-lasting effects
Cons
- The weed's leaves need to be dry
Best weed killer for hard surfaces
Flow/AmazonKeeping your driveway, paths, and patio clear of weeds can feel like an uphill task. Using an acetic acid-based formula (think industrial-strength vinegar) can really make all the difference. As an added bonus it's an organic and biodegradable option. This 'Super Strength' solution from Flow is specially designed for hard surfaces but can be used on gravel and stones too. This comes in five, 10, 20, and 25-litre quantities, all of which include a spray bottle.
Customer review: "Cleared a driveway. Wasn't hopeful but it actually has seemed to have worked."
Pros
- Organic
- Spray bottle included
Cons
- Has a strong smell
Best weed killer for moss
Pro-Kleen/AmazonIf you're plagued by both weeds and moss, consider Pro-Kleen's "NOGrow" weed killer that manages to successfully target both. This ready-to-use solution comes in a five-litre bottle that can cover approximately 50 square metres. The bottle comes with a handy trigger sprayer to save you from decanting it into a separate container. This should work within 24 hours and is safe for children and pets once it's dry.
Customer review: "Brilliant for killing weeds, spray on weeds and they are dead within hours, really good product."
Pros
- Comes with a trigger sprayer
- Works on annual and perennial weeds
Cons
- Can't be used on grass
Best biodegradable weed killer
Hytol/AmazonThis is another acetic acid-based option which makes it naturally biodegradable. This is a convenient ready-to-use option, but you will need a separate sprayer or watering can to apply it to your problem weedy areas. In the right dry conditions this is fast-acting option and will leave your ground ready for replanting after three days.
Customer review: "It does the job. No complaints. Great value for money and it kills the weeds on my drive. I would recommend this product."
Pros
- Covers 500 square metres
- Can work within hours
Cons
- No sprayer included
How we chose the best weed killer
All of these weed killers have been hand-selected by our team of Modern Gardens shopping experts. We carefully considered how eco-friendly and effective they are in our selection of the best. Our team has spent hours investigating and researching weed killers to make it easier for you to find the very best, and we'd never recommend a product we don't believe in.
Where possible, we also test and share the latest and best products you should know about. And with help from Modern Gardens Magazine, Garden News and Garden Answers, we share expert gardening knowledge to help you get the most from your product.
How to stop the return of weeds
You've got rid of those pesky garden weeds, but how do you make sure they stay away? Here are a few easy tips to keep them out of your garden and prevent them from coming back.
Apply weed killer at the right time
In order to maximise the performance of your weed killer, you need to give it the chance to absorb into the plant uninterrupted, and where possible apply it to a fully formed weed so there's an increased surface area for the solution to sink into.
The best way to do this is to make sure to leave it be, no lawn mowing, and to check the weather forecast before applying. Rain and high winds can affect the weed killer's performance and this could be easily avoided by prepping in advance.
Fertilise your grass
It might not seem it with the number of weeds that can appear on our lawns, but grass is tough and will win out over weeds in the quest for nutrition. By keeping your grass healthy and fertilised with water, nitrogen, and potassium, it'll stop weeds from having the chance to breakthrough, and keep your lawn looking thick and luscious too.
Products like Miracle-Gro EverGreen Complete 4-In-1 Treatment are great allies, feeding both the lawn and ousting weeds in one fell swoop.
Don't leave any bare soil
Leaving your soil unoccupied by plants is just asking for weed growth. Where possible, make this soil home to other plants you'll actually want in your garden, for gorgeous displays and to keep the weeds at bay.
Reduce digging
Sometimes this can't be helped with pets, but try to only dig up the soil in the garden when and where it is needed. Turning up and mixing the soil can bring weeds closer to the surface, giving them the opportunity to sprout and show face.
Put a weed control fabric under paving
Weeds growing between the cracks on your driveway or patio are frustrating to see and a chore to pull out. To keep them away, and save you time and effort in the long run, you can peg a weed control fabric under your patio, decking, paths, and driveway.
A weed control fabric, also known as a weed control membrane, is a specially designed covering sheet that blocks UV from seeping through to deep seeds and preventing any unwanted plant growth. We'd recommend GardenMate's Woven Weed Control Fabric as a great example that's affordable too.
How to kill weeds without weed killer
If you'd rather avoid weed killer altogether, Geoff Hodge, gardening expert to Modern Gardens, shares his recommendations for other tools you can use:
Weed extractors
Tap-rooted perennial weeds, such as dandelions, can be tricky to dig out, especially in lawns. That’s where a weed extractor, like the Fiskars Light Weed Puller, is invaluable. Push its teeth over the crown of the weed and it grips the taproot so you can lever it out. You don’t need to get down on your hands and knees, and the leverage action is easy.
Hoes
A hand fork is useful for digging out established perennial weeds, but long-handled hoes can be used standing up, putting less pressure on your back. Hoeing doesn’t disturb the surrounding soil as much as digging.
Weed burners
Ideal for clearing weeds from paving areas, weed burners produce high temperatures (600C-1,300C) that
cause a plant’s cell walls to burst and the plant dries out and dies. The idea is to heat, not burn them. Some ‘burners’ are flameless and use electricity to heat the weed, like the Hozelock Green Power Thermal Weeder. Others use LPG canisters, like the GoSystem Gardening Weed Burner.
Physical barriers
Most weed seeds need light to germinate, so covering the soil helps stop them growing. You can use a 5-7.5cm (2-3in) thick layer of organic bark, compost or cocoa shells; or, lay a strong, semi-permeable membrane or weed-control fabric like the GardenMate option above. These materials ensure vital air, moisture and nutrients can pass through, but vary enormously in quality – look for a 10-year+ guarantee.
Home remedies
Did you know there are actually several natural 'weed killers' you can concoct in your own home?
Boiling water: Yes, you can actually just use boiling water from your kettle to oust pesky weeds but it may take several attempts to work. This method works best on weeds that appear on your patio or pathway (to prevent damaging other plants) and on young weeds if possible - it will only kill the part of the weed the boiling water comes into contact with.
Salt: Sprinkling salt on your weeds dehydrates the plant leaves, preventing the roots from taking up water and ultimately killing the weed off. It's a good solution for those hard-to-reach areas a mower can't reach but it is a slower process taking up to several days.
Vinegar: A classic household ingredient for cleaning and tackling weeds too! Vinegar with a high acetic acid concentration will effectively kill weeds, though be careful when applying as like a weed killer, it'll kill anything that's green.
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Amy-Mae Turner is a Commerce Content Writer for Modern Gardens, Yours, Take A Break Pets, and A Modern Kitchen. When she's not pottering in the garden or mucking around in the kitchen, she can be found having doggy cuddles with her two beloved cockapoochis.