Crab grass, dandelions and thistles are some of the most common weeds in the home landscape. Whether they are growing in your lawn, cracks of your driveway or in the garden, you can help prevent weeds before they emerge with a preemergent herbicide. Apply in areas where weeds grew the previous year to create a barrier that prevents the roots from becoming established just after germination. Then, enjoy a weed-free landscape where plants and desired grasses can thrive.
Read the labels carefully and select an appropriate preemergent herbicide to apply on your surface with your type of weeds. For example, if you want to prevent crab grass from growing on tall fescue grass, choose a herbicide such as benefin that will effectively prevent the crab grass from germinating without harming the tall fescue.
Time applications of preemergent herbicides so they will work effectively. Apply the herbicide at least a week before the weeds germinate, usually in early spring when nighttime temperatures begin to reach at least 50 degrees Fahrenheit. Ask your local extension office about the best to time to apply the herbicide. Once you see the weeds, it is too late and you should instead apply a postemergent herbicide.
Wear garden gloves and protective clothing when working with herbicides. Keep children and pets indoors. Adhere to any other precautions as written on the label.
Apply the preemergent weed control with a handheld or push broadcast spreader. Set the dial to dispense the herbicide at a rate recommended on the label. This will differ among herbicides and where you are applying it. Spread it as even as possible.
Water the herbicide into the soil with a sprinkler, irrigation system or handheld hose. Apply as much water as the label indicates, usually about ½ to 1 inch. Lay out a pie pan and measure how deep it fills up to estimate about how much water you are using. If rain meets this need at least one week before the weeds are expected to germinate, there is no need to water.