Weeds and unwanted grass do not stand a chance when you attack them with Roundup spray. The active ingredient in Roundup is glyphosate. Glyphosate will effectively kill almost any kind of plant upon contact as it travels through a plant's tender tissues down to the roots. Because Roundup must travel through the entire plant, it may take several weeks for the chemicals to work and the plant to die.
Choose a day that is sunny, dry, calm and above 60 degrees F for best application results.
Wear long pants, long sleeves and gardening gloves as you apply the Roundup to protect your skin from the chemicals.
Cover surrounding plants with the plastic tarp to protect them from the Roundup spray, if desired.
Adjust the nozzle of the spray so it either foams onto the plants or sprays onto the plants. If you need to control the application of the Roundup and protect surrounding plants, choose the foam setting. If this is not a concern, choose the spray setting.
Apply the Roundup to the desired area, directing the product so it completely saturates all of the foliage of the undesired plant, as well as the base of the plant.
Reapply the Roundup to the plants if the plants are not completely dead after two weeks.