Grass and weeds emerging from cracks in an asphalt driveway are a common sign of pavement deterioration. The root systems of these plants can expand within the cracks, accelerating the damage by widening the asphalt’s structural weaknesses. Addressing this vegetation promptly is necessary to maintain the integrity and appearance of the paved surface. The process involves immediate removal methods, treatments, and long-term preventative maintenance.
Immediate Physical Removal
Removing the visible grass is the first step. A small flat-head screwdriver or a specialized weeding knife can be inserted into the crack to pry out the plant, aiming to extract the root crown entirely. Specialized crack scrapers or wire brushes are useful for clearing away smaller, more superficial growth and the accumulated organic debris that feeds it. Using a wire brush also helps to loosen any trapped soil and prepare the fissure for subsequent treatments. If the root remains in the crack, the plant will likely regrow, making complete extraction the goal of this initial labor.
Non-Toxic Treatment Methods
For a non-chemical approach, thermal and acidic treatments using common household items can effectively eliminate vegetation from the asphalt. Boiling water is a straightforward thermal method that kills the plant by causing immediate cellular damage. Carefully pouring water heated to a rolling boil directly onto the grass ensures the heat penetrates down to the root structure. This method is nontoxic and leaves behind no residual chemicals.
Another common non-toxic solution involves high-concentration vinegar, which works due to its acetic acid content. Standard household white vinegar typically contains about 5% acetic acid, which primarily desiccates the above-ground foliage. For a more powerful treatment that can better reach deeper roots, horticultural vinegar with an acetic acid concentration of 10% to 20% is recommended. Applying the vinegar solution on a dry, sunny day enhances its effectiveness, as the sun’s heat accelerates the acid’s destructive action on plant cells.
A mixture of salt and dish soap added to vinegar also increases its effectiveness, with the soap acting as a surfactant to help the solution adhere to the grass blades. It is important to use these salt-based solutions sparingly and only within the confines of the driveway cracks. Salt is a non-selective contact killer that can sterilize the soil, preventing any future plant growth in the immediate area, which can be detrimental to nearby lawn or garden beds if overused.
Commercial Chemical Options
When immediate and systemic elimination of tenacious grass is required, a commercial non-selective herbicide is often employed. These products are designed to kill nearly all plants they contact. Glyphosate-based solutions are common non-selective options that are absorbed by the foliage and translocated throughout the entire plant, reaching and killing the root structure.
Applying these chemicals requires careful technique to prevent damage to desired surrounding vegetation. A pump sprayer with a focused nozzle should be used, keeping the spray tip low and close to the weed to minimize drift. It is recommended to apply herbicides on a calm day to ensure the product remains localized within the crack. Overspray or runoff onto the asphalt sealant can sometimes cause discoloration or damage if the product is not used according to the manufacturer’s directions.
Preventing Future Growth
After successfully removing and treating the grass, the long-term solution involves eliminating the environment that allowed the growth to begin. The cracks must first be thoroughly cleaned of any residual soil, dead roots, and debris using a wire brush or compressed air. This prepares the asphalt for a permanent repair that seals the crack against future seed germination.
Once clean, an asphalt crack filler or a specialized self-leveling sealant should be applied to fill the void completely. For deeper or wider cracks, a foam backer rod can be inserted first to provide a stable base and reduce the amount of sealant needed. This repair step prevents water from penetrating the sub-base and stops new seeds from lodging in the crack.
Beyond crack filling, regular driveway sealing is necessary to maintain a uniform, protective barrier across the entire surface. Asphalt driveways should typically be sealed every two to five years, depending on traffic volume and local climate conditions. A fresh sealant coat helps to repel water, prevent UV damage, and inhibit the formation of new cracks where grass could otherwise take root.