To avoid regrowth after pulling weeds, spray commercially available weed killer into the cracks. If you are concerned about the effect of chemicals on the environment, however, a number of organic options can kill weeds. Applying table salt to the cracks will make the soil underneath chemically unbalanced, causing weeds to wither and die. Pouring boiling water on the weeds and in the cracks might also be effective. Another solution is a mixture of 1 cup table salt dissolved into1 gallon household vinegar and 1 tablespoon dishwashing detergent. Spray on the weeds and repeat as necessary.
Weeds seem to grow virtually anywhere, even poking leaves out of cracks in concrete expansion joints on driveways and sidewalks. While newly laid concrete doesn’t have such problems, settling produces cracks after several years, allowing weed seeds to gain a foothold. Although hand pulling will temporarily remove this unwanted greenery, sections of roots often remain, allowing weeds to regrow.
Filling the cracks is another, possibly more effective alternative. For an organic solution, try shredded bark or pebbles. Polymeric joint sand, a mixture of regular sand and resin, solidifies to a mortar, blocking air, water and light from reaching weed seeds and roots.
Chemical, Organic Controls
Sealing the Cracks
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.
When to Kill Pavement Weeds
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.
Click Play to Learn How to Get Rid of Weeds
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.