Aim the nozzle at the weeds or grasses you want to kill and saturate the plant until it is wet. If you are trying to spot-kill weeds or grasses mixed in with plants you do not want to kill, shield those plants with either plastic or cardboard to prevent accidentally getting the weed killer on them. If plants get accidentally sprayed, thoroughly rinse them off with water immediately.
Roundup Weed & Grass Killer should only be used when there is little or no wind to prevent the wind from carrying the mist through the air and hitting other plants.
The product can be used virtually anywhere outside where you have unwanted weeds or grasses. There is no harm in applying it in a vegetable garden as long as the vegetable plants are shielded while spraying the weeds or grasses. It can also be used on patios, driveways, around trees and near fences.
To get the best results, apply Roundup Weed & Grass Killer when it is sunny and the temperature is 60 degrees Fahrenheit or warmer.