Does vinegar kill weeds?
Absolutely, YES! Vinegar is an effective weed killer.
Do I need special vinegar?
Yes, not all vinegar will work. Specifically you're looking for ones with high acidity, many reports recommend over 10% in some cases even 20%.
Acetic acid is what makes vinegar an effective weed killer.
Regular old household vinegar which is usually 5% acetic acid may wilt the weeds but they will quickly regrow. In most cases it will do nothing.
How does it work?
Acetic acid will kill any plant, regardless of the source. It absorbs moisture from the leaves and quickly kills and shrivels the weed.
Vinegar is non selective, it will kill every plant it touches. It is also a contact only weed killer, meaning it will only kill the parts of the plant it touches.
It may not work on deep rooted weeds which can simply regenerate. from deep underground.
Is it safe to use vinegar as a weed killer?
For the most part it is safe. Be warned higher concentrations of acetic acid can be extremely dangerous.
10-20% acetic acid vinegar is potent stuff. Use safety gloves, eye gear & a face mask at all times. If you get it on bare skin it will quickly burn as if you've stuck your hand on a grill.
Vinegar is acidic so overuse can quickly alter your soil PH causing all sorts of harm and prevent future growth.
Benefits of vinegar vs commercial weed killers?
- It's relatively cheap and readily available.
- Can work very quickly, sometimes taking as little as couple of hours to eliminate small weeds.
- Once sprayed it isn't likely to be harmful to the environment, your pets or your children.
- Kills most garden weeds in one application.
- No need to exclude kids or pets from the area.
- Can be used in areas with edible crops.
What are the disadvantages of using vinegar?
- Higher acidity means much more danger.
- May not kill deep rooted or larger weeds.
- Isn't as effective as commercial weed killers.
- Cannot be used on lawns.
- Lower acidity vinegars may not work at all.
- Can affect soil PH if over sprayed.
How to use vinegar as a weed killer:
There is no need to dilute vinegar, it's already in liquid form which makes it easy for the plant to absorb. Diluting it will only decrease the effectiveness.
Do I need any tools to use it?
A sprayer bottle or pressure sprayer will be useful for applying accurately and to a large area.
Remember to use safety equipment for your eyes, hands & mouth if using 10% concentration or above.
Pour it on or spray it on undiluted:
Simply spray it onto the weed covering the leaves & stems.
Be careful not to get any on any plants you wish to keep and don't allow the vinegar to seep into the soil if you plan on replanting after killing the weed.
Combine it with salt:
Add some salt to increase the effectiveness. If used in combination it may better protect against regrowth.
Combine with salt and dish soap:
Dish soap (regular ole Fairy works well) reduces the surface tension of the plant allowing the salt and vinegar to be more easily absorbed, increasing the effectiveness of both.
Best practices for effective use:
Use on a sunny day when the weeds are in full sun. If you do this it isn't uncommon for small weeds to die within hours.
Don't use on windy days as it may blow the vinegar onto plants you wish to keep causing them to die.
How effective is it?
It's highly effective against small or new weeds that haven't become established and don't have energy stores to regrow.
Vinegar is a contact killer, for the most part it will only kill the parts of the weed it touches. It won't travel through the plant and kill the roots like most commercial weed killers.
It won't be effective against large invasive species like knotweed or brambles.
Precautions to take:
If using a high acidity vinegar please use safety gloves, eye protection and a face mask. If it gets on you it will BURN!
Vinegar can lower the PH of your soil making it more acidic and inhabitable for plant life, please don't overuse it.
On that note, if you're clearing an area of weeds and wish to plant something there like putting down grass seed then leave plenty of time between application and the start of seeding a new lawn, this will give your soil PH time to recover.
What are the alternatives?
Weed control is an emotive subject and many recommend against the use of commercial weed killers such as Glyphosate. In all cases it's better to take a pro active approach to stop weeds from growing in the first place.
Read our article on 6 other homemade weed killers and see if any of them are suitable.