Claims like “This burns weeds in 1 day! They NEVER grow again” are almost always exaggerated.
Here’s what the evidence shows:
- Boiling water can quickly kill the above-ground parts of small weeds, especially those growing in cracks in driveways or sidewalks. However, weeds with deep or extensive roots often grow back.
- Household vinegar (about 5% acetic acid) may scorch weed leaves, particularly young annual weeds, but it usually does not kill the roots of established perennial weeds. Stronger horticultural vinegar is more effective but can cause serious skin and eye burns and must be handled carefully.
- Salt can kill plants, but it also remains in the soil, making it difficult for desirable plants to grow. It’s generally not recommended except in places where you want no vegetation at all (such as cracks in pavement).
- Soap is sometimes added to sprays to help them stick to leaves, but it is not an effective weed killer by itself.
The only way to ensure a weed “never grows again” is to remove or kill the entire root system or prevent new seeds from germinating. Even then, new weeds can appear later from seeds blown in from elsewhere.
For long-term control:
- Pull weeds, including as much of the root as possible.
- Apply mulch in garden beds to block sunlight and reduce germination.
- Remove weeds before they produce seeds.
- If needed, use an appropriate herbicide according to the label, taking care to avoid desirable plants.
No single household product reliably kills all weeds in one day and guarantees they will never return.
