How to stop weeds from growing in concrete slab joints

Updated February 21, 2017

Concrete slabs form the basis of walkways, patios, driveways and paths through the gardens and landscapes of many homes. They protect grass and plants from foot traffic and mark borders or edges of garden areas. While the slabs are resilient and can withstand wear and tear, the joints between the slabs are susceptible to problems, including invasive weeds sprouting up wherever they can see sunlight between the pavers. Stopping these weeds from growing will ensure the ideal look and feel for your landscape.

Wear garden gloves when working with weeds. Pull young weeds from the base, gently and slowly tugging to avoid breaking the stems. If you pull correctly, you will pull out the whole root, eliminating the weed. Pulling weeds is only effective if you can pull the whole root and stop the weed from dropping new seeds.

Spray herbicide glyphosate onto broken or exposed weed stems. If the weeds are full, trim the heads off to expose the stems, and then treat with glyphosate. The herbicide kills weeds and absorbs into exposed stem or root material more quickly and effectively .

Fill a spray bottle or garden sprayer with boiling hot water. Spray the hot water carefully and precisely into all of the joints in the concrete slab. The boiling water will cook all weeds and most weed seeds, stopping future weed growth.

Repeat application of glyphosate or boiling water as needed if more weeds appear. You can also treat the slabs with either water or the chemical every two to three weeks to prevent new weeds from starting.


If you can move your concrete slabs to perform maintenance below, a layer of landscape fabric under the slabs may help prevent weed growth. This is not recommended for all types of slabs and all installation areas, however, so consult the slab manufacturer or a professional installer before trying this.


Boiling water will kill any plant that it contacts, and glyphosate will kill any broadleaved plants. Be careful to keep these materials away from desirable plants, including grass.

Things You'll Need

  • Garden gloves
  • Glyphosate
  • Spray bottle or sprayer
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About the Author

Samantha Volz has been involved in journalistic and informative writing for over eight years. She holds a bachelor's degree in English literature from Lycoming College, Williamsport, Pennsylvania, with a minor in European history. In college she was editor-in-chief of the student newspaper and completed a professional internship with the "Williamsport Sun-Gazette," serving as a full-time reporter. She resides in Horsham, Pennsylvania.