Answer: Pouring boiling water on weeds can be used especially in situations where other plants are not nearby, such as in cracks in patios or sidewalks. Boiling water will act as a contact "herbicide", killing only the portion of the plant it comes in contact with. It is most effective on young, newly emerged weeds.
Can You Use Vinegar Instead of Water? Simply boil the vinegar and apply or spray it in the same way on any stubborn weeds that you want to eliminate. And this is a double-whammy as it works both ways.
The most effective homemade option is a mixture of white vinegar, salt, and liquid dish soap. Each of these ingredients has special properties that combine to kill weeds. Both the salt and the vinegar contain acetic acid, which serves to dry out and kill the plants.
Acetic acid is a terrific weed killer but it is also a terrific plant killer! Acetic acid works by drawing all of the moisture out of the weed or plant leaf. It is quick to work and it would be common to see a weed or plant brown up after only a few hours of having vinegar applied to its leaves in the full sun.
Vinegar and salt will dry out weeds and grass, whereas the dish soap helps the vinegar and salt to cling to the leaves rather than absorbing the mixture. If utilized correctly, they may be an effective herbicide.
Vinegar kills weeds quickly—usually within 24 hours—but does not discriminate between the weeds you want to kill and the plants you want to grow, so apply the vinegar carefully and in the right conditions. Vinegar's efficacy depends on the weather and the solution's concentration.
Rock salt is actually a super-effective and totally natural weed killer that is ace at clearing a gravel driveway. Simply sprinkle some rock salt on the ground surrounding any weeds you can see and then sit back and watch as the salt kills the weeds in just a matter of days. It's almost unbelievable.
Undiluted bleach can zap weeds growing through the cracks in your walkway or driveway. Spray undiluted bleach on the weeds and let stand. The solution will kill existing weeds and help prevent new ones from sprouting. Bleach will kill grass, flowers, and other vegetation as well, so take care where you aim!
Glyphosate is systemic, will kill grass and pretty much every other plant it touches. Used to kill annuals, perennials, woody perennials and tree stumps - it is effective against ALL weeds. Glyphosate is used with 85% of GM crops grown globally.
A tea kettle is often a good way to safely and precisely apply the boiling water directly to the weed. Use plenty of water and plan to retreat 7-10 days later as one application rarely kills the entire plant, especially deep-rooted weeds.
The Dangers of Using Vinegar in Your Garden
Vinegar is a contact or "burndown" herbicide, killing what it touches within hours or days. The worst part is that it may looks like it's working, but weeds will then resprout from the roots, particularly perennial species.
Generally, vinegar is categorized as a natural or organic weed killer. So, it lures many people to believe its use is safe. However, the opposite is true as it is a corrosive substance. It is acetic acid (the chemical that kills weeds).
Saltwater can actually be a natural option to tackle those pesky weeds in your garden! It works by dehydrating and damaging the plant tissues, leading to their demise. However, it's crucial to be cautious when using saltwater as a weed killer, as it can also harm the soil and surrounding plants.
When concrete is exposed to temperatures above 212° F (the boiling point of water), the moisture in the concrete turns to steam. If the temperature rises more rapidly than the steam can escape through the concrete matrix, the rising pressures exceed the strength of the concrete and it begins to break apart and spall.
Salt (sodium chloride) works to kill weeds by dehydrating the plants and disrupting the internal water balance of the plant's cells. Since salt is water-soluble, it is most effectively applied when mixed with water as this makes it easier for the weeds to absorb.
The Takeaway. To eradicate weeds effectively, the roots need to be killed, not just the top growth, which synthetic weed killers do successfully. The bottom line is that mixing vinegar with Epsom salts or table salt and liquid dish soap does not make a safe, effective weed killer.
Vinegar is an effective means of controlling weeds, but it depends on how concentrated it is. For more powerful weed killers, mix 1 part white vinegar to 2 parts Epsom salt with liquid dish soap like Dawn. When applied when the weather is hot and sunny, vinegar Epsom salt weed killer is highly effective.
Lay a weed proof membrane or fabric foundation before laying the gravel. This will stop weeds from growing in your driveway and spreading their roots into it.
Glyphosate, the ingredient in Roundup and other products, is translocated from the leaves to the roots of a weed. Vinegar is not translocated. It is true that 5% vinegar (acetic acid) will kill young, tender weeds but it does little damage to established weeds.
Vinegar with a higher concentration of acetic acid tends to control weeds more effectively. Household vinegar is generally 5% acetic acid. Some herbicidal vinegar products are 20% or 30% acetic acid. In general, 20% or 30% acetic acid is more effective because it more completely kills young leaves and growing points.