how to stop weeds from growing in cracks

How to stop weeds from growing in cracks

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 would have long disappeared.

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.

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 sprouting out the pavement cracks around the landscape.

Here are some common, effective ways to control the weeds and grasses that infiltrate the cracks in paved surfaces. If a recipe calls for salt, make sure to limit its use to hardscape areas only; do not allow the salt to run into lawns and gardens.

Click Play to Learn How to Get Rid of Weeds

The Spruce / Jayme Burrows

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, and any plant that sends its roots down below the slab has access to it.

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.

When to Kill Pavement Weeds

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

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.

How to stop weeds from growing in cracks

Pack the crack tightly with sand before filling it with a quick-drying joint sealant. Cut the sealant’s tip and insert it directly into the crack. Squeeze the product into the crack and overfill to allow for the shrinkage that occurs after drying.

Spray the weeds with a 5-percent acetic household vinegar. Concentrate the spray on the weeds, reapplying several times over a two- to three-day period or until the weed tops and roots are dead.

Aside from being aesthetically unpleasant, weeds poking through sidewalks pose several threats to your asphalt, and family. If left unattended, the weeds will thrive, grow and can eventually create severe concrete deformations and heaving, which is only mended by tearing out the slab. Larger weeds are also tripping hazards, and will continue to reemerge after countless applications of herbicides. Manually eradicate the weeds before prepping the cracks and applying a quick-drying joint sealant.

Dig out as much of the weed as possible before cleaning out any remaining dirt or debris from the crack with water and a stiff wire brush. Allow the concrete to dry before continuing.

Allow the crack sealer to dry for 12 to 24 hours, or according to the package directions. Examine the crack and reapply, if necessary, to fill any remaining small holes or voids in the hardened product.