Summertime and weeds might go hand-in-hand, but you don't have to give up any enjoyable summer activities to spend time fighting these unwanted plants. Chemical-based weed killers can be effective, but not an ideal solution if you have kids or pets in your household. Instead, using natural vinegar- or plant oil-based sprays can help you quickly get rid of weeds, even those ugly eyesores sprouting up between the bricks in your sidewalk.
Weed Spray Ingredients
The same white vinegar you use to make salad dressings also works as an inexpensive, eco-friendly weed killer. That's because store-bought vinegar contains approximately 5 percent acetic acid, a substance that strips the protective waxy cuticle off of plant foliage. Several organic gardening supply companies sell vinegar-based products that contain up to a 20 percent concentration of acetic acid, a dosage that knocks out even the most stubborn weeds.
Plant-based oil sprays can also quickly kill weeds with ingredients such as cinnamaldehyde, which comes from cinnamon, or orange, lemon, oregano or clove oils. These oils destroy the cell membranes of plants, causing the weeds to dry out and die. Some organic weed control products combine plant-based oils with vinegar to give those pest plants an effective double whammy.
How Weed Sprays Work
Most vinegar- and plant oil-based sprays are designed to use as foliar treatments on weed seedlings or broadleaf weeds. Because the ingredients only work on contact, the sprays typically kill the above-ground parts of the plant and leave the roots unscathed, so weeds with extensive taproom systems often regenerate. Some annual weeds susceptible to natural sprays include common chickweed (Stellaria media) and ground ivy (Glechoma hederacea). Vinegar sprays even work on hard-to-kill crabgrass (Digitaria spp.). As an added bonus, using multiple vinegar treatments can temporarily increase the acidity of the soil so new weeds can't take root.
Using Weed Sprays
For vinegar- or plant-oil based sprays to work effectively, you must thoroughly cover the above-ground portion of the pest plant. Spray the weeds until the foliage and stems glisten with moisture. Apply treatments on warm, dry days when rain isn't predicted for your area for at least 24 hours because the natural ingredients quickly degrade in water. Spray the weeds around your sidewalk every two weeks until you achieve control.
Effects on Bricks
Vinegar-based sprays are particularly useful for spot-killing any weeds sprouting between bricks in sidewalks. Vinegar is frequently used to clean brick floors, patios, barbecues and fireplaces, so take advantage of vinegar's natural acidic properties and scrub your sidewalk with a stiff-bristled brush after spraying nearby weeds. Although weed-control products containing plant-based oils won't permanently damage your sidewalk, they might leave behind a temporary stain on the bricks.
Use even natural weed-control sprays with caution, because accidental exposure to direct spray can harm people, animals and desirable plants. Before spraying weeds, put on protective clothing, including goggles, waterproof gloves, long pants and a long-sleeved shirt. Don't allow children or pets near the treated sidewalk until the solution has thoroughly dried. Because vinegar and plant-based oils are non-selective, they can damage or kill wanted plants along with the pest plants. Weeds that sprout between bricks are mostly isolated, but spray carefully so the solution touches only the unwanted plants. As always, follow the application instructions on the manufacturer's label when using a store-bought herbicide.