Has your lawn been invaded by weeds?
A few weeds here and there might not be an issue, but if they become unsightly or start crowding out the grass, then many homeowners turn to weed control options to get their lawns back. Even if you don’t care much about weeds in the lawn, you might live in an area where an HOA mandates weed removal.
If you’ve looked at your options for weed control, then you’ve probably heard of pre-emergent herbicides. These herbicides control annual weeds in your lawn. When you or your lawn care provider apply pre-emergent herbicides at the right time of the year, it prevents new annual weeds from growing. It won’t get rid of existing weeds, but it’s a great way to control the growth of new weeds in the spring or fall.
What Are Annual Weeds?
Like annual flowers (such as moss rose, celosia, and petunia), annual weeds only survive for one growing season. They can still come back year after year, though, because they sow new seeds in the lawn after they flower.
Annual weeds that can show up in Texas lawns include bittercress, chickweed, crabgrass, henbit, rescue grass, purple dead nettle, sandbur, and sow thistle. Some of these weeds start growing in the spring, while others are more likely to sprout in the fall and grow through the winter.
How Do Pre-Emergents Work?
Pre-emergent herbicides stop weed seeds from getting a foothold in the lawn. The pre-emergent chemicals inhibit seed cell division and create a barrier between weeds and the soil that stops roots from growing.
Though sometimes you’ll see claims that pre-emergents prevent seeds from sprouting, in reality, these herbicides don’t stop weed seeds from germinating. Instead, they kill the weeds right after they germinate. Depending on the type of weed, the pre-emergent typically kills it right after the first root or the first leaf sprouts.
When Should You Apply Pre-Emergent Herbicides?
The best time to apply pre-emergents depends on soil temperature. You want to apply the herbicides before weed seeds start to sprout, but not so soon that it has time to wash out of the soil before it can kill the sprouting weeds.
In Texas, you’ll usually apply pre-emergents in early March, or before the soil temperatures are consistently over 55 degrees Fahrenheit. To control winter weeds, you’ll apply pre-emergents in late September or early October, or before temperatures at night consistently drop below 60 degrees. Always check the label of the pre-emergent that you buy for more specific application guidelines.
What Types of Pre-Emergents Are There?
Like other herbicides, you can get selective or non-selective pre-emergents. Selective herbicides target specific types of weeds. For example, if you had a lot of crabgrass in your yard last year, you might pick a selective herbicide that targets crabgrass. Alternatively, if you want to plant lawn grass after applying pre-emergent herbicide, you can choose a selective herbicide that targets broad-leaf weeds instead of grassy plants. Non-selective herbicides affect all types of plants. Use non-selective pre-emergents if you want to stop all seeds from germinating in your yard.
Different pre-emergents also have different windows for how long they are effective at stopping seeds from growing. With some, you can plant new grass seed just a couple weeks after applying the pre-emergent. With others, you might have to wait up to six months before the pre-emergent is completely gone from your lawn. Always check the label for details about the specific herbicides you pick.
Are There Organic Options?
If you prefer not to use chemical herbicides on your lawn, there is one organic option for pre-emergent weed control. Corn gluten meal is commonly recommended as a solution for pre-emergent weed control. It’s a by-product of corn processing, and it’s completely natural. However, reports are mixed as to its effectiveness.
You can purchase pure corn gluten meal for use as a fertilizer (it contains nitrogen) or as a pre-emergent. There are also some brands of organic lawn care products that offer natural weed preventers that contain a stronger version of corn gluten meal.
Should You Be Cautious about Pre-Emergents?
As with any lawn care product, carefully follow label directions when applying a pre-emergent. Follow all safety recommendations and application guidelines.
The main thing to be cautious about with pre-emergent herbicides is that they can stop grass seeds from growing. Depending on which pre-emergent you use, you might have to wait up to several months after pre-emergent application to seed new grass into the lawn.
If you use corn gluten meal and also plan to apply fertilizer close to the same time, make sure you pay attention to how much nitrogen is in both fertilizers. You might need to choose a fertilizer with low nitrogen content to balance out the nitrogen from the corn gluten meal and avoid over-fertilizing the lawn.
What Tools Do I Need?
How you apply pre-emergent herbicide depends on whether you use a liquid formula or a granular formula. For liquid herbicides, a sprayer is the best tool to use. For granular herbicides or corn gluten meal, a spreader will help you apply the herbicide evenly.
There is a wide range of sprayers and spreaders available. A compact, hand-held, canister sprayer will work well for most homeowners who want to apply liquid herbicides. For granular herbicides, a drop-spreader gives you precise control over application while a broadcast spreader helps you cover more ground quickly.
Here at Richardson Saw, we carry broadcast spreaders from Shindaiwa and Echo. These reliable, easy-to-use spreaders make herbicide application simple. For sprayers, we recommend STIHL and Echo’s manual and powered sprayers for homeowner and commercial use. These reliable brands provide sprayers of the highest quality. Check out our “Buying Guide: Sprayers and Spreaders for Home and Professional Use” for more information.
