Applying Pre-Emergent Herbicide

There are several different ways to apply a pre-emergent herbicide. Understanding how this type of herbicide works and when to apply it during the year will go a long way to making it as effective as possible.

How a Pre-Emergent Herbicide Works

This type of herbicide is used early in the growing season and prevents seeds from germinating as the weather becomes warmer in the spring. The herbicide creates a barrier and seal around the seed, making it impossible for the seed to sprout and a new plant to grow. It is important not to aerate after applying the herbicide because aeration can break the seal around the seed. If you decide to aerate your lawn, complete the process before using a pre-emergent herbicide.

Applying the Herbicide

The two most commonly used methods of applying a pre-emergent herbicide include using a spray bottle and a lawn spreader.

You can purchase pre-emergent herbicides already mixed and in spray form. When you use the sprayer, target specific areas in your lawn or garden. Remember where weeds grew last season and expect seeds to have been left there in the ground. If you can identify and locate these potential weed areas, you can apply herbicide before they start to grow.

You can use a sprayer effectively after you pull out small weeds that have already started growing. Thoroughly soak the area by spraying the herbicide on the location where the weed was located. Although this method can be time consuming, it will be effective in preventing newly emerging plants from becoming established weeds. You can effectively eliminate new quack grass seedlings and the more resistant rhizome root systems by pulling small growth first and then applying the herbicide.

If you do not purchase the herbicide pre-mixed, you will need to buy the herbicid and mix it with water before placing it in a sprayer. Backpack sprayers are good for applying herbicides because they have a pump-pressure spray handle, are easy to use and make traversing a large yard less of an effort.

The other method of applying a pre-emergent herbicide is by spreading granules on the lawn with a spreader. Granules are often combined with lawn fertilizer, making this type of application doubly effective. Spreaders with a small bin can be handheld. Spreaders have crank handles or wheels and both kinds automatically disburse the granules. Dispurse granules throughout  the entire lawn and then turn on the sprinklers or hose to water the grass in order to activate the herbicide.

Later in the Year

Once the weather begins to warm it is usually too late to use pre-emergent herbicides. Instead, use a post-emergent herbicide. You should target weeds that have already become established when using post-emergent herbicides and you will need to apply them several times over the course of the summer.  Switch back to applying a pre-emergent herbicide in the late fall to help prevent further growth of weeds in the coming spring.