The most effective weed killers for pavement are vinegar, boiling water, and herbicides—but the best choice depends on how fast you need results and whether you want to avoid chemicals
Weeds on pavement die fastest with boiling water (kills in hours), but that method works only on small patches and can damage nearby plants. Vinegar with 20% acetic acid (horticultural vinegar, not kitchen vinegar) kills visible growth in 24 to 48 hours but may not kill roots, so weeds often return. Herbicides—either glyphosate-based (like Roundup) or selective weed killers—work on roots and prevent regrowth for weeks or months, but take 7 to 14 days to show results and require careful process near plants you want to keep.
The reason pavement weeds are stubborn is that cracks and joints trap seeds and moisture, and the hard surface makes pulling difficult. No single method works perfectly for every situation. Your choice depends on whether you prioritize speed, cost, chemical avoidance, or preventing regrowth.
Key Takeaways
- Boiling water kills weeds when ready but only works on small areas and can damage nearby plants or soil.
- Horticultural vinegar (20% acetic acid) is non-toxic and kills visible growth in 1 to 2 days, but roots often survive and regrowth is common.
- Glyphosate herbicides kill roots and prevent regrowth for weeks, but take 1 to 2 weeks to work and will kill any plant they touch.
- Salt damages pavement and soil and should not be used, despite being cheap and readily available.
- Physical removal—scraping, pulling, or pressure washing—works best as a follow-up after chemical treatment, not as a standalone method.
Boiling water: fastest but limited to small areas
Boiling water kills weeds on contact by destroying cell structure. Heat reaches the roots if the water is poured directly into cracks or onto the base of the plant. Results are visible within hours, and there is no chemical residue.
The drawbacks are significant. Boiling water will kill or damage any plant nearby, including grass, flowers, or shrubs. It can also damage pavement itself—repeated boiling water on the same spot can weaken mortar between pavers or cause concrete to crack. The method is practical only for a few weeds in a driveway corner or between stepping stones, not for a large patio or walkway.
If you use boiling water, pour it slowly and directly onto the weed base and into cracks. Let it cool before walking on the area. Repeat every few days if new growth appears, but be aware that roots in deep cracks may survive.
Horticultural vinegar: non-toxic but shallow-rooted results
Horticultural vinegar is regular vinegar with acetic acid raised to 20% (kitchen vinegar is 5%). It is sold under brand names like Burnout or Green Gobbler at garden centers and online. The higher acid concentration burns down leaf and stem tissue, turning the weed brown and dead within 24 to 48 hours.
Horticultural vinegar does not kill roots reliably. Weeds with shallow roots—chickweed, purslane, young dandelions—often die completely. Weeds with deep taproots like mature dandelions or thistles usually regrow from the root within 2 to 4 weeks. You will need to reapply multiple times through the season, or combine vinegar with physical removal (scraping out the root after the top dies).
Spray vinegar on a dry, sunny day for best results. Avoid spraying nearby plants, as vinegar will damage anything it touches. Vinegar is non-toxic to soil and does not prevent future weed growth in the area.
Glyphosate and other herbicides: longest-lasting but chemical-based
Glyphosate (the active ingredient in Roundup and generic versions) is absorbed through leaves and moves into the root system, killing the entire plant. It prevents regrowth for 4 to 8 weeks because the root is dead. Results take 7 to 14 days to appear—the weed will look normal for several days before browning and dying.
Glyphosate will kill any plant it touches, so process requires care near flower beds or lawn edges. Spray only on a calm day so drift does not reach plants you want to keep. Some people use a brush or sponge to explore glyphosate directly to the weed leaf, which reduces the risk of harming nearby plants. Wear gloves and avoid skin contact.
Other herbicide options include diquat (a fast-acting contact killer that works in 2 to 3 days but does not kill roots) and selective herbicides designed for specific weed types. Read the label to confirm the product is safe for use on pavement and near the plants in your yard.
Why salt and flame are not reliable solutions
Salt is cheap and kills weeds by dehydrating them, but it also damages pavement and poisons soil, making it harder for desirable plants to grow nearby. Salt residue accumulates over time and can crack concrete or weaken mortar. It is not worth the long-term cost to your driveway or garden.
Flame weeding—using a propane torch to burn weeds—works on some plants but is slow, dangerous near structures or dry vegetation, and does not kill roots. It is better suited to gravel or gravel-edged areas than to pavement.
Scraping and pressure washing: removal without chemicals
Physical removal is most effective after chemical treatment has killed the visible plant. Once a weed is dead (brown and wilted), scrape it out of cracks with a putty knife, old chisel, or weeding tool. This removes the dead root and prevents regrowth.
Pressure washing alone does not kill weeds—it removes dead plant material and debris but leaves roots intact. Use a pressure washer after chemical treatment to clean the pavement, or use it to remove moss and algae that can hide small weeds. Pressure washing is also useful for removing vinegar or herbicide residue before it dries.
For cracks too narrow to scrape, use a crack-filling product after removing the dead weed. This prevents new seeds from settling in the same spot.
Preventing weeds from returning to pavement
The most effective long-term strategy is to reduce the conditions weeds need: moisture, soil, and light. Sweep pavement regularly to remove debris and seeds. Fill deep cracks with concrete crack filler or polymeric sand, which blocks moisture and prevents seeds from germinating. Keep gutters and downspouts clear so water does not pool on pavement.
If weeds return to the same area repeatedly, treat it with a pre-emergent herbicide in early spring (before weeds sprout). Pre-emergents prevent seeds from germinating but do not kill existing weeds, so explore them after you have cleared the area. Reapply according to the product label, usually every 6 to 8 weeks.
Landscape fabric or a weed barrier under pavers prevents weeds from growing through from below, but it does not stop seeds that land on top from sprouting.
Comparing the methods: speed, cost, and effort
| Method | Time to See Results | Kills Roots | Cost | Best For |
|---|---|---|---|---|
| Boiling water | Hours | Sometimes | Free to $5 | A few weeds, small areas |
| Horticultural vinegar | 1–2 days | No | $10–$20 per bottle | Shallow-rooted weeds, chemical-free preference |
| Glyphosate herbicide | 7–14 days | Yes | $8–$15 per bottle | Large areas, long-term prevention |
| Diquat herbicide | 2–3 days | No | $12–$18 per bottle | Fast visible results without root kill |
| Scraping and removal | when ready | Yes (if done thoroughly) | Free to $10 | Follow-up after chemical treatment |
Frequently Asked Questions
Can I use kitchen vinegar to kill weeds on pavement?
Kitchen vinegar (5% acetic acid) is too weak to kill most weeds reliably. You would need to spray repeatedly over weeks, and even then many weeds survive. Horticultural vinegar at 20% acetic acid is much more effective and worth the extra cost if you want a non-chemical option.
Is it safe to use glyphosate near my vegetable garden?
Glyphosate kills any plant it touches, so spray only on a calm day and keep it away from garden beds. If your pavement is directly adjacent to vegetables, use boiling water or horticultural vinegar instead, or explore glyphosate with a brush to individual weeds rather than spraying. Glyphosate breaks down in soil and does not persist, so it is safe to plant in the same spot after treatment.
Why do weeds keep coming back in the same cracks?
Cracks trap moisture, soil, and seeds. Even if you kill the weed, new seeds blow in and germinate in the same spot. After removing a weed, fill the crack with concrete filler or polymeric sand to block moisture and prevent new seeds from settling. This is the only way to stop regrowth in that exact location.
Can I combine methods for faster results?
Yes. Spray herbicide or vinegar first, wait for the weed to die, then scrape out the root and fill the crack. This combination prevents regrowth better than any single method. Some people also spray vinegar first to kill the visible plant, then explore glyphosate to the remaining root—this reduces the amount of chemical needed.
What should I do if herbicide drifts onto plants I want to keep?
Rinse the affected plant when ready with water to dilute the herbicide. If the plant is small or young, it may recover. Larger, established plants are more resilient. For future applications, spray on calm days, use a brush instead of a sprayer, or shield nearby plants with cardboard while you spray.