How to Kill Weeds in Sidewalks, Driveways and Patios

By
Kathleen Connolly
KConnolly_headshot_Lorenz_MG_4506.jpg
Kathleen Connolly

Kathleen Connolly has been an advanced master gardener and accredited organic lawn care professional for over 30 years, specializing in lawn care, horticulture, and landscape design.

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Updated on 08/05/22
Reviewed by
Kathleen Miller
Kathleen Miller
Reviewed by Kathleen Miller
Kathleen Miller is a highly-regarded Master Gardener and horticulturist with over 30 years of experience in organic gardening, farming, and landscape design. She founded Gaia's Farm and Gardens, a working sustainable permaculture farm, and writes for Gaia Grows, a local newspaper column.
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Grass growing between cement cracks in sidewalk

The Spruce / Jayme Burrows

Project Overview
  • Working Time: 30 mins - 1 hr
  • Total Time: 1 hr - 3 days
  • Skill Level: Beginner
  • Estimated Cost: $5 to $50

Grasses and weeds growing out of pavement cracks in sidewalks, driveways, and patios is a common annoyance. Sometimes it seems as though these unwanted plants grow even better in tiny pavement crevices than they do in the lawn and garden. This defies all logic since pavement surfaces are brutally hot and dry places where you might think that nothing could survive. But not only do these tenacious grasses and weeds survive, but they also seem to positively thrive in this no man's land of blistering hot pavement.

And because of this genetic tenacity, grasses and broadleaf weeds that sprout up through the cracks in the pavement are very hard to control. It is easy enough to pluck the top off at pavement level or sever them with a string trimmer, but unless you extract or kill the entire root, the plant often simply sprouts up again. 

The reality is that pavement weed control is an ongoing landscaping maintenance task for homeowners, but the work is easier if you have a variety of workable strategies to choose from.

When to Kill Pavement Weeds

You can stay on top of weed control by devoting a bit of time to the job each week. Many homeowners like to conclude weekly mowing or garden work with a few minutes spent plucking or killing the weeds that sprout out the pavement cracks around the landscape.

You will quickly recognize that various weeds have their favorite seasons, and are vulnerable to different control methods. The damp spring might be best suited to plucking weeds by hand, while during the dry months of late summer, chemical herbicides might be the better strategy.

Before Getting Started

Successful weed control begins with knowing your foe's likes and dislikes and habits. In their own way, weeds are marvels of genetic evolution.

Driveway and sidewalk cracks turn out to be surprisingly friendly places for weeds. These cracks can hold a considerable amount of soil and organic matter, a perfect bed for grass and weed seeds, which are often very tiny. And just below the surface of the paving there is often trapped moisture that can be accessed by any plant that sends its roots down below the slab.

Some grasses and weeds thrive in the heat. Crabgrass, for instance, is a warm-season annual grass that thrives in driveway and patio cracks. Its seeds are very tiny and can penetrate the smallest cracks. Quackgrass is even more diabolical because it is a perennial weed that can survive even if just small pieces of root remain beneath the slab. If the exposed portion of the grass is removed, a new shoot will pop up in no time at all. 


In cold weather, a dark-colored asphalt driveway absorbs sunlight and keeps the soil beneath warmer than the surrounding landscape. Some grasses and weeds can easily tolerate the salts in ice-melt products. Fescue, for instance, is a cool-season grass that is somewhat salt-tolerant and might have a good chance of surviving through the winter in a driveway. Sedge is a grass relative that tends to stay green in winter. And then there are the cold-happy weeds such as chickweed that seem to scoff at temperatures at which other plants have long disappeared.

In other words, the weeds and grasses that thrive in pavement cracks do so because they are genetically well adapted to the conditions created by concrete, brick, or asphalt paving. It will take repeated efforts using a variety of methods to control these invasive super plants.

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Click Play to Learn How to Get Rid of Weeds

What You'll Need

Equipment / Tools

Handpicking Method

  • Small screwdriver
  • Shop vacuum
  • Caulk gun

Boiling Water Method

  • Pot
  • Small screwdriver
  • Shop vacuum
  • Caulk gun

Vinegar Method

  • Spray bottle
  • Small screwdriver
  • Shop vacuum
  • Caulk gun

Propane Torch Method

  • Weed torch with fuel tank
  • Small screwdriver
  • Shop vacuum
  • Caulk gun

Herbicide Method

  • Garden sprayer
  • Small screwdriver
  • Shop vacuum
  • Caulk gun
  • Face mask
  • Rubber gloves

Materials

Handpicking Method

  • Water
  • Asphalt or masonry caulk

Boiling Water Method

  • Water
  • Asphalt to masonry caulk

Vinegar method

  • Household white vinegar or agricultural vinegar
  • Salt
  • Lemon juice (optional)
  • Dish soap (optional)
  • Asphalt or masonry caulk

Propane Torch Method

  • Asphalt or masonry caulk

Instructions

How to Kill Pavement Weeds by Handpicking

The time-honored method is still one of the best. By carefully pulling the weeds in a way that extracts the entire plant, root and all, you will prevent the weed from resprouting.

  1. Make Sure the Soil Is Moist

    Pulling weeds will be easiest after moisture from rainfall or a garden hose has softened the soil in the cracks and the underlying soil that is holding the roots. Thoroughly moisten the weed before pulling.

    Water being poured over weeds in between concrete pavement

    The Spruce / Almar Creative

  2. Extract the Plant

    Carefully and slowly pull the weed with a gentle wiggling motion. The goal is to extract the entire plant, root, and all, if possible. This will prevent the weed from resprouting. A small screwdriver is a good tool for loosening the roots on the weed.

    Weeds pulled out from pavement with garden gloves

    The Spruce / Almar Creative

  3. Fill the Cracks

    After removing as much of the weed as possible, vacuum out the crack first, then fill it with mortar or masonry caulk to seal it. 

    Mortar caulk poured in between pavement to prevent weeds

    The Spruce / Almar Creative

How to Kill Weeds With Boiling Water

Water that you boil for cooking can be put to good use as a weedkiller rather than pouring it down the drain. Though many weeds like somewhat hot conditions, none will tolerate steaming water. Make sure you do not use water that has oils or meat leftovers from cooking.

  1. Carry Boiling Water to the Weeds

    Use oven mitts to carefully transport a pot of boiling water to the pavement cracks where weeds are growing.

    Pot of boiling water hovering over weeds between pavement

    The Spruce / Almar Creative

  2. Scald the Weeds

    From a low height, carefully pour of the steaming hot water over the weed. Pour slowly and allow the water to completely saturate the weed, right down to the roots.

    Boiling water poured over weeds between pavement

    The Spruce / Almar Creative

  3. Wait, Repeat

    Some tenacious weeds with long tap roots may require repeated treatment with boiling water. After two or three treatments, though, just about any weed will surrender. At this point, the dead weed be plucked out, and the remaining hole vacuumed clean of soil and filled with masonry caulk

    Boiled weeds pulled out from pavement with garden gloves

    The Spruce / Almar Creative

How to Kill Pavement Weeds With Vinegar

A mixture of salt and white vinegar (5 percent acetic acid) spread on pavement will kill most weeds and grasses.

  1. Mix the Solution

    Combine 1 cup of salt (about 228 grams) and 1 gallon (about 3.8 liters) of white vinegar (5 percent acetic acid) together in a large plastic jug. To make it even more caustic, add 1 cup (about .28 liters) of lemon juice. To increase sticking power, add 2 tablespoons (about 28 grams) of dish soap. If you have it, pickling vinegar is more acidic than regular white vinegar and probably more effective.

    Tip

    An even better weedkiller can be made with horticultural vinegar. It may be hard to find in local stores, but it can be ordered online. This type of vinegar is 20 percent acetic acid. Mix it with some orange oil and a bit of phosphate-free dish soap. Acetic acid burns the plant's top growth, depriving it of the ability to photosynthesize. Make sure you use protection for your hands and eyes; it is acidic and can burn you.

    Cup of salt poured into plastic container of vinegar

    The Spruce / Almar Creative

  2. Apply the Weedkiller

    Fill a small pump spray bottle with the vinegar solution, then carefully spray the pavement weeds, completely saturating the exposed foliage.

    Salt and vinegar solution sprayed on weeds between pavement

    The Spruce / Almar Creative

  3. Remove the Weed, Fill the Crack

    Wait several days, then pluck the dead weed from the pavement crack. Vacuum as much soil from the crack as you can, then fill it with masonry or asphalt caulk.

    Vacuum hose sucking up soil from pavement crack after weed removal

    The Spruce / Almar Creative

How to Remove Pavement Weeds With a Propane Torch

An ordinary propane torch can be used to burn weeds sprouting up through pavement cracks. Many weeds tolerate a fair amount of heat, but not the 2,000 degrees produced by a propane flame. Some manufacturers now offer long-handled weed torch tools specifically for this purpose.

  1. Prepare the Torch

    Carefully mount the fuel tank on the torch handle. Open the valve slightly and use a spark lighter or match to light the torch. When the flame ignites, open the valve fully.

    Torch handle connected to propane tank over weeds

    The Spruce / Almar Creative

  2. Incinerate the Weed

    Move the live flame back and forth over the weed until it turns black and becomes charred. Be careful not to char the concrete or melt the asphalt, however. After destroying the weed, allow the area to cool completely, extinguishing any embers with water, if necessary

    Propane torch scorching weeds between pavement

    The Spruce / Almar Creative

  3. Clean and Fill the Crack

    After the pavement cools, carefully dig and vacuum out as much of the dead weed and soil as you can. Fill the crack with masonry or asphalt caulk.

    Flat knife digging up burnt weeds from pavement crack

    The Spruce / Almar Creative

How to Kill Pavement Weeds Using Non-Selective Weed Killer

Chemicals should be a last resort, but if other methods fail, spot-treating grasses and weeds with a weed-killer containing glyphosate (such as Roundup) will kill the plant, roots, and all. Any chemical product should be used carefully, but glyphosate does not linger in the environment the way the chemicals in some other weedkillers do. Other types of weedkillers may work on broadleaf weeds, but they will not kill grasses growing in pavement cracks.

  1. Mix Weed Killer

    In a garden sprayer, mix glyphosate-based herbicide, carefully following label directions.

    Warning

    Make sure to wear protective gear (face mask and gloves) whenever applying herbicide.

    Weed herbicide poured into garden sprayer

    The Spruce / Almar Creative

  2. Apply the Weed Killer

    Drench the exposed portion of the weed in herbicide spray. Allow the weed to remain for a day or two until it's clear that it is dead. When the weed is clearly dead, water thoroughly to soften the roots of the weed.

    Weed killer sprayed on dense weeds between pavement cracks

    The Spruce / Almar Creative

  3. Clean and Fill the Crack

    Use a small screwdriver and shop vacuum to remove as much of the weed root and soil as possible from the crack. Then, fill the crack with asphalt or masonry caulk.

    Screwdriver digging up weed root from between pavement

    The Spruce / Almar Creative

How to Repair Wide Cracks in Concrete
    Article Sources
    The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

    1. Crabgrass. University of Georgia Extension.

    2. Quackgrass Management. University of Vermont Extension.

    3. Tall Fescue. Oregon State University Extension.

    4. Flame Weeding. University of Vermont Extension.

    5. Glyphosate General Fact Sheet. National Pesticide Information Center.