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.
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.
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
Thanks to 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.
Kathleen Connolly has been an advanced master gardener and accredited organic lawn care professional for over 30 years. She specializes in lawn care, horticulture, and landscape design. Kathleen earned a Master's Degree in Landscape Planning and Design and Sustainable Land Use Planning and Design.
Before Getting Started
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, they alsoseem to positively thrive in this no man’s land of blistering hot pavement.
The Spruce / Jayme Burrows
When to Kill Pavement Weeds
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.
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.
An alternative solution to eliminating weeds from your driveway is to pour boiling water on them. Boiling water is a natural, Eco-friendly alternative to chemical-based herbicide. The scalding-hot temperatures will instantly kill weeds upon contact. Best of all, it’s completely free and takes only a couple of minutes to make.
In addition to lawns and flowerbeds, weeds can also appear in small cracks in the driveway or sidewalk. So, what’s the best way to prevent weeds from appearing in these cracks?
Trying to prevent weeds can seem like a never-ending battle. You may pull up one weed, only to discover two more that have taken its place. To make the problem worse, weeds can emerge just about anywhere.
If you have weeds growing in your driveway, you should first eliminate them. Assuming they are growing in small cracks, however, you probably won’t be able to pull them up entirely – not without breaking them in half, at least. Therefore, it’s recommended that you use an herbicide to kill them.
After the weeds have died, you should seal the cracks in your driveway to prevent them from coming back. Even if you eliminate the weeds currently taking refuge in your driveway, there’s a good chance of them returning in the future – unless, of course, you seal the crack.
Homemade Vinegar Herbicide
To seal cracks and crevices in your driveway, pick up some cement filler at your local home improvement store. Most major home improvement stores sell this filler for about $7 to $10 per tube, which is a small price to pay for protecting your driveway from weeds. After the cement filler has hardened, it will form a solid barrier to protect your driveway from the intrusion of weeds.
The only downside to using boiling water is that it may cause serious burns if you accidentally spill it on yourself. So, if you plan on using boiling water, carefully pour it over the crack to minimize the risk of injury. You may even want to wear gloves when handling a pot of boiling water for this very reason.