The Strongest (And Best) Weed Killers For Your Garden

weed growing from ground
Written by Dean Wilson

Weeds are a pest that plague every garden. It’s important to keep on top of them if you want to maintain a healthy lawn and garden space. Sadly the moment you forget about weeds in your garden, is the moment they’re back to spoil the party.

Gardeners used to use sodium chlorate in the UK, but it was banned across Europe in 2009 for safety reasons. And though you can no longer use anything quite as strong (or hazardous), there are still plenty of super-strength options to choose from. We’ve found and rated some of the strongest weed killers available to buy in the UK.

See below for our comparison of strength, effectiveness, safety and cost. We only choose the best products, so you can feel confident that the best pick below will be the right one for you.

Value Pick
Weedol Ultra Tough Weed Killer Liquid Concentrate (6+2 Tubes)
8 x 25ml Tubes
from £8.95
Also Consider...
Roundup Tough Weedkiller 1L
1 Litre

Last update on 2019-10-17 / Affiliate links / Images / Pricing from Amazon Product Advertising API

Best Pick: Barclay Gallup (Strongest Available In UK)

Will kill all known weeds – strongest available in UK

As the strongest weed killer available in the UK (for uncertified use anyway), Barclay Gallup is our #1 best choice.

Most weeds will be killed in a single application, which is a relief if you’re used to pulling the same weeds time and again. This product will work its way into the roots – meaning that you’re killing the entire weed for good. At 24ml per 1 litre of water, this stuff is highly concentrated, which also makes it quite a dangerous substance to deal with.

Caution is advised during use and the only down-side is that given the product’s strength, there are a number of rules which are sensible to follow during use. The product should not be used in windy conditions to prevent it drifting onto eyes and skin – or on to valuable garden plants. It may also make some areas of your garden into temporary ‘no go’ areas for kids and pets.

This product cannot be used in temperatures lower than 8°c and is likely to be less effective in temperatures under 16°c. For this reason, you should only buy this product if you’re able to use it in warm weather conditions.


  • Strongest product available – if this doesn’t work then nothing will.
  • One litre of this stuff can be used on over 1,600m2 of land.
  • No pulling of weeds required.


  • Only suited for use during warmer summer months.
  • It is hazardous and toxic in its concentrated form; caution is advised during use.
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Value Pick: Weedol Ultra Tough

Low cost tubes for use with a pump sprayer or watering can

Our value pick is Weedol Ultra Tough, which comes in individual tubes of concentrate, ready to dilute with water in a pressure sprayer or watering can.

Although the separation into separate tubes means less overall coverage than some of our other reviewed products, a coverage of 240m2 is still decent.

Unfortunately, as this product is incredibly strong, meaning it cannot be used on lawns (as it would cause the grass to die-out). This stuff won’t prevent the growth of new weeds, but it is a systematic weed killer – meaning that it is absorbed into the plant, root and stem. This means once the weed is dead, it’s not coming back.

Weedol will kill bindweed, pigweed, dandelion and every other common form of weed easily. It will even deal with more stubborn, deep-rooted weeds like bramble, thistles and docks. Just be careful where you do spray it because it doesn’t discriminate – it will just as easily kill your beloved garden plants as it will any other plant.

For maximum effectiveness be sure to use it in warm, dry weather – ideally during spring and summer months.


  • Very effective – will kill the root as well as the plant.
  • Single-use tubes are handy for regular use round the garden.
  • Still has decent coverage for a smaller, value pack.


  • Keep this product well clear of any plants or lawn you’d like to keep!
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Roundup Tough Weed Killer 1L (Highly Concentrated)

The best weed killer for those with pets or children

A very strong candidate for our best pick, Roundup Super Concentrate is a tough formula that is pretty powerful for such a small bottle.

At only a single litre it seems expensive on first look, but when you realise that this product can cover up to 3,000m2 you realise that this product will last a significant number of years, even in larger sized gardens.

Roundup even include a visual guide on the back of the bottle to help you understand where this product can (and cannot) be sprayed. There are a number of practical uses including the clearing of an overgrown area and the removal of weeds from places like driveways, patios and other masonry work.

A major benefit of this product over our top pick, is that unlike Barclay Gallup, children and pets do not need to be kept away from the treated area (at least once it has dried). That’s a major bonus if either of these groups use your garden regularly. The soil will naturally degrade the product over time, making it harmless to humans and animals alike.

You should look to wait a minimum of 7 days before digging or plating in soil that has been treated with Roundup.


  • Highly effective at killing weeds from root to tip.
  • Highly concentrated with a huge coverage – this product should last a number of years for many people.
  • Clear instructions for use – including guidelines on what not to do.


  • It’s definitely on the pricier side, though worth it if you have a large area to cover.
  • You will need to ensure that you monitor the maximum yearly dose.
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Doff Knock Down

Individual sachets in powder form – low-cost but slow-acting

Like Roundup, Doff’s formula is sold in 10 individual sachets, for use on separate occasions. This is quite handy, as it makes the measuring of the mixing amounts easy.

Doff is very slow-acting – it’s likely that you won’t see results for up to 3 weeks, which is an incredibly long time to wait. Nevertheless, it is effective. It just takes a little longer than some of the other options available.

Given its strength we would advise not to use this product around animals and children. We’d probably also steer clear of this product if you have deep-rooted weeds you need rid of like bramble, thistle etc.

Doff is made from Glyphosate, which is the most commonly used weed killer in the world, so you would expect it to be as effective as many of the other well-known brands – just without the polished branding and higher price.


  • Separate sachets make it easy to mix; convenient for separate uses.
  • It is effective at killing weeds, provided you use it during the warmer months of the year.
  • Comes in a powder format, so it is lighter than the liquid weed killers featured above.


  • Coverage is a lot less than some of the other products reviewed.
  • Slow-acting process – can take weeks to see results.
  • Cannot be used by those with animals and children.
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Miracle Gro Roundup Fast Action

The second Miracle Gro product to be featured in our list, this product is another from the biggest weed killer manufacturer in the UK.

While their ‘Fast Action’ product isn’t as strong as their ‘Tough’ formula, this product is different in that it aims to kill unsightly weeds quickly. It even comes with an attached sprayer to help quickly and easily distribute the formula across your garden.

This is all well and good, but we found that often this doesn’t deal with the root of the weed – which is the real problem, as they will soon grow back if the root is left alive.

For this reason, we wouldn’t recommend this product unless you’re looking for a weaker product that is going to be safer for the environment and any inhabitants of the garden.


  • Weaker formula which is environmentally safer for your garden.
  • Fast-acting: it will kill weeds in just 1-2 days (though they might well re-appear within a few weeks).
  • Includes a pump action sprayer, reducing the overall cost.


  • Not overly effective – often you’re only dealing with the surface issue rather than the real problem.
  • The wand used to spray the product is incredibly short, which is slightly inconvenient but not the end of the world.
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How To Get Rid of Garden Weeds

Garden weeds are one of the most unwelcome pests in a home garden, spoiling the aesthetics and actively strangling your plants at the root.

Thankfully, with the right focus and dedication, weeds can be eradicated and with preventative measures they can be kept away for good.

Once weeds have embedded themselves in the ground, you’ll pretty much need to remove the entire root structure or they’ll eventually return, even with the use of a weed killer.

That’s why prevention is the best cure. Follow these tips to keep weeds out of your garden for good:

Limit the amount of digging taking place

Because the seeds of weeds remain dormant for many years, digging can actively disrupt them and bring them nearer the surface, where they’ll receive adequate sunlight & water to grow. As a general rule – if you don’t need to dig up an area of your garden, then don’t. Leave dormant seeds where they are.

Mulch as much as you can

Not only is mulch beneficial to your garden plants, but it serves a key role in blocking sunlight that would otherwise help weed seeds to grow. Mulch is also the perfect breeding ground for bugs such as crickets, which will actively seek out and eat weed seeds. Some will also use carboard or weed control fabric underneath the mulch as a solid barrier to prevent sunlight from reaching the seeds.

Use thick weed control fabric under new paths, patios, artificial grass & decking

This is something that most gardeners will do as standard, but it’s surprising how many do not. Without sunlight weeds can’t grow – it’s the best method of prevention full stop.

Don’t leave any bare soil

The moment that you leave bare soil in your garden, you offer weeds the perfect environment from which to grow. It’s a simple one but always a rule you should follow.

Regularly fertilise your lawn

Given its surface area and accessibility, your lawn is likely a hot-spot for weeds. By fertilising your lawn regularly, you encourage the growth of healthy grass. This helps the grass to out-grow any weeds, as the grass monopolises the space, oxygen and sunlight available. Pulling and treating any lawn weeds will also help to expedite this process.

Whatever you do, be sure to pick up some strong weed killer, a pair of garden gloves (for the stinging type) and even a daisy picker (or simple garden fork) to help with the heavy lifting.

About the author

Dean Wilson

I'm an avid gardener and home DIY enthusiast from Yorkshire in the North of England. I'm passionate about helping our readers get out into their gardens - by making the most of the outdoors and ensuring they get the best possible deals on their gardening equipment. I also believe strongly in the preservation of our beautiful garden wildlife.

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