Homemade Weed Killer UK
Hey there, I am Chelsey, founder of Good Grow.
In recent years there has been an explosion of articles describing strong homemade weed killer recipes using household staples such salt, vinegar, bleach and even boiling hot water: the problem is... Do they really work?
We've tried all the so called DIY weed killer recipes and I will say the results are rather disappointing. Don't get me wrong it is commendable that you want to use less weed killer but homemade weed killers are a poor substitute for a strong or long lasting weed killer.
Strong Homemade Weed Killer Recipes?
In short DIY weed killers are less effective than there commercial counterparts and in some cases they aren't effective at all. Don't get me wrong, if your weeds are weak or young then they may just be enough to tip your weeds over the edge.
Lets get this started and you can decide for yourself whether homemade weed killers are for you...
Is Salt an Effective Weed Killer?
One of the oldest and most talked about DIY weed killers. They say the Romans salted the ancient city of Carthage following the siege of the last Punic war, I'll leave the history lesson for someone else...
How to use salt as a weed killer?
Many will suggest you dilute the salt with water but the easiest and most effective way to use salt as a weed killer is to apply it directly from the container onto the weeds, like this:
Is it safe?
Salt is safe but be warned it can be harmful to insects / bugs & slugs.
Your soil won't like it either, to make salt effective as a weed killer you need to use an awful lot of it (more than you think) which can result in very bad soil health preventing replanting.
Salt is not harmful to humans or pets.
How effective is it?
We used salt and applied it directly to the weeds as instructed above, we used a whole container, the results are below:
Should you use salt as a weed killer?
Do not use salt in your lawn or around ornamental plants. Salt is persistent in soil and it can take many months for rainwater to wash it away - this may even result in it getting places you don't want it. Using it on your lawn will harm grass, leaving yellowing and bald patches.
Salt is best used on hard surfaces not intended to bear vegetation such as driveways, gravel, block paving etc. It is easily applied to weeds growing through cracks or around edges but don't expect miracles, you will need a lot of salt and it may not be effective at all.
Small, weak or young weeds may die when you apply salt directly to them.
Salt will damage most kinds of plant, this is why the myth of using it as a weed killer never seems to die, people see their weeds being damaged and assume it's going to work but they soon recover.
Forget about using salt to kill deep rooted weeds like Brambles, Ivy, Nettles or Dandelions.
The headline cost of 27p may make it seem like salt is a cost effective way to kill weeds but this is misleading. One container of salt will only treat roughly 1m2 and it won't kill your weeds.
A traditional commercial weed killer such as Glyphosate can treat 1m2 for roughly 10p and it will kill 99% of all your weeds - salt is not cost effective when compared to strong weed killers.
Can you use Vinegar to kill weeds?
We've done salt but will it's close friend vinegar be any better at killing weeds?
We tested regular old distilled vinegar, you do get "agricultural vinegar" but it's not a homemade weed killer - you're unlikely to have it at home! It's a proper strong commercial weed killer.
How to use vinegar as a weed killer?
Just like salt many online guides say to dilute vinegar with water - we're not sure why as this dilutes it making it less effective. The best way to apply vinegar is to splash it on neat.
You can do this right from the container or decant it into a sprayer...
Is it safe?
Regular malt or distilled vinegar is perfectly safe. It's not harmful to humans or pets.
Agricultural vinegar is a completely different beast. The active ingredient in vinegar is acetic acid, regular vinegar contains around 5% acetic acid, agricultural vinegar contains 20%.
If you have some agricultural vinegar on hand then be sure to read the label for safe use.
How effective is it?
We used distilled vinegar and applied it directly to the weeds as instructed above, we used a whole container, the results are below:
Should you use vinegar as a weed killer?
Vinegar is best used on hard surfaces such as driveways, patios & paths. You can also use it in borders - vinegar is a contact weed killer meaning it only damages plants it touches.
Please do not use vinegar in your lawn. It can be troublesome spraying accurately and grass can & will be damaged by even regular ole household vinegar.
Vinegar will also make your soil more alkaline inviting pests such as moss, do not use it in your lawn - it's not worth the trouble.
Regular vinegar isn't a very effective weed killer. It will damage weeds, if your weeds are shallow rooted, young or weak then it may just be enough to tip them over the edge.
Regular household vinegar won't kill your weeds.
A whole bottle of vinegar costs less than £1 (depending on which type / brand you buy), this is enough to treat a small amount of weeds.
Sadly when compared to a commercial weed killer vinegar isn't cost effective, it costs more per m2 and it's much less effective at killing weeds.
Agricultural vinegar: typically a 5 litre container will cost around £25, it's not concentrated and is applied straight onto the weeds. Compare this with a 1 litre bottle of Glyphosate (£15) which will make 5 litres and is much more effective against a larger range of weeds.
Is bleach a safe & effective weed killer?
Bleach! The stuff you use to disinfect your home? As a weed killer!?
Yes you heard it here, people have been using bleach as a weed killer. Let me be clear, I do not recommend you use bleach as a weed killer, it is toxic to the environment & people.
We've tested it so you don't have to.
How to use bleach as a weed killer?
Bleach is an efficient disinfectant but when using it as a weed killer great care should be taken.
Unlike the other home made weed killers you will need some equipment to use bleach as a weed killer. You will need safety gloves, a spray bottle, bleach & some water.
Dilute the bleach with water according to the instructions on the label then spray it onto your weeds.
Is it safe?
NO! Bleach isn't safe to use as a weed killer. It is toxic to humans, insects, aquatic animals & everything else. Please do not use bleach as a weed killer, it may even be illegal to do so in your area.
Not only is bleach not safe but it can also stain concrete, all these factors combined should put you off using bleach as a DIY weed killer.
Never ever mix bleach with other chemicals to create a a homemade weed killer recipe - it's dangerous.
How effective is it?
We used bleach mixed with water to treat a small amount of weeds, it didn't kill them:
Should you use bleach as a weed killer?
I don't want to be a kill joy but you shouldn't use bleach as a weed killer, anywhere!
If you use it on soiled areas you run the risk of poisoning the ground, harming the soil and the insects that live in it. Rainwater will wash it away possibly into areas with plants you'd like to keep. Never, ever use bleach on your lawn.
If you must use bleach then use it on hard surfaces but be warned you run the risk of staining or damaging your path, patio or paving.
As can be seen from above, bleach doesn't fully kill weeds - at least not as effectively as a strong weed killer would. It will kill grassy, shallow rooted weeds - fairly easily.
Larger, long established, deep rooted weeds will not be affected by bleach. It was never designed to be a weed killer and like agricultural vinegar it will simply burn away the visible parts of the weed leaving the roots intact, allowing the weeds to regrow from there.
If bleach killed weeds it probably would be very cost effective.
£1 for a bottle and you can dilute it at a 1:5 ratio sadly it isn't an effective weed killer and it's highly toxic. When compared to a traditional weed killer you will get much better results with something that was designed to kill weeds (Glyphosate, Tricoplyr etc).
Does boiling hot water kill UK weeds?
Is it another homemade weed killer myth? Can you really kill weeds with boiling hot water?
How to use boiling hot water to kill weeds
Seriously, this must be one of the easier home made weed killers, boil up the kettle and pour it onto your weeds, that's it! All you need is a kettle or some other method of boiling water.
Is it safe?
Along with salt & vinegar boiling hot water is one of the safest weed killers you can make yourself. The only risk it carries is burning yourself or someone else. Please exclude pets and children whilst using hot water to kill weeds, we don't want any accidents.
How effective is it?
First thing, you will need quite a lot of boiling hot water to damage your weeds. It may take several trips from the kettle to the weeds, not ideal if you have a large garden or a lot of weeds.
We tried using 5 kettles full of boiling hot water to kill some small weeds, the results weren't impressive:
Should you use hot water as a weed killer?
Almost anywhere your weeds grow! Boiling hot water isn't very effective at killing weeds but it certainly damages them, repeated application may just be enough to kill some small weeds.
One thing to note: Never use boiling hot water in your lawn to kill lawn weeds, it's almost impossible to accurately apply it and it will damage your grass.
You shouldn't put boiling hot water in sprayers, the scalding water will deform the plastic damaging your sprayer in the process.
Forget about using boiling water to kill deep rooted weeds, it won't work regardless of the amount you use - it will just stun the weeds.
Repeated application of boiling water may be enough to kill some small or newly established weeds. You'd be quicker just pulling them out by hand!
Hot water is cheap (FREE!) but ineffective except against the weakest weeds.
Your mileage with hot water as a weed killer will vary but in this case we would say it's a cost effective buy lousy, time consuming way to kill weeds.
Conclusion
So you've seen our experiments with so called "homemade weed killers" as you can see none of them were particularly effective, they all to some degree damaged the weeds but none died.
Don't believe the hype!
These garden myths have been doing the rounds for a long time.
Yes it is admirable that you want to use less commercial chemical weed killers but these homemade versions are no substitute for the real thing - even vinegar which is much touted only works when you buy agricultural vinegar but that's just another commercial, toxic chemical.
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