How to Use Post-Emergent Herbicides Safely


Sep 07, 2019

Share the Love!

Taking care of post-emergent weeds can be tricky. You want to kill the weeds, but not your grass. You don’t want to just cut your lawn, but be on the cutting edge.

But no matter what you do to prevent weeds from growing, those pesky lawn-wreckers pop their ugly little heads up out of the soil anyway. There are too many for pulling, so what now?

Here are a few tips for fighting back against weeds using post-emergent herbicides.

What Are Post Emergent Herbicides?

How to Use Post-Emergent Herbicides Safely 1

Simply put, post-emergent weed control is a strategy to take on weeds that have already popped up. There are things you can do to try and prevent weeds from ever showing up, but once they do, post-emergent herbicides are your new best friend.

Post-emergent herbicides use combinations of chemicals to kill the weeds and (hopefully) prevent them from coming back. They do this by attacking the roots of the weed or even the leaves. Some weeds are tougher to kill than others.

You will want to choose your herbicide carefully and consider a few basic questions.

What kind of weeds are you targeting?

Is it a stand-alone weed patch?

Will contact with other plants (such as your grass) be unavoidable?

How safe is it to use around your family and pets?

What extra safety precautions will you need to take?

Different Types of Post-Emergent Herbicides

How to Use Post-Emergent Herbicides Safely 2

Believe it or not, there are different types of post-emergent herbicides out there on the market. That’s actually a good thing! The different types allow you to pick one that will be most effective for the exact situation you’re facing.

Systematic vs Contact

The first two types of post-emergent herbicides to understand are “systematic” and “contact” herbicides. They each work differently and have different uses.


Systematic herbicides are absorbed by the weeds. The product flows through the plant, killing it from the inside out, roots and all. They’re a great choice for when you’re dealing with perennial weeds that you don’t want to see now…or next year.


Just like it sounds, this type of herbicide kills weeds on contact. They work by destroying the leaves and stem of the plant. With the exposed portions destroyed, the weed cannot continue its life cycle and dies. Contact herbicides are the right choice for annual weeds and small weeds.

Selective vs Non-selective

The next choice you need to make is selective vs non-selective herbicides. This is a crucial choice. If you choose the wrong one, you can risk damaging some of your lawn or landscaping.


As the name suggests, selective herbicides are choosy. They target certain weeds and will only harm those specific plants. If you’re having weed problems in your lawn that’s close to some landscaping plants you’d rather not harm, a selective herbicide will allow you to kill the weeds without harming the plants you like.


You guessed it. Non-selective herbicides don’t ask questions, they just kill everything in sight. If you’re looking to clear out a patch that has been overtaken by weeds, this is your weapon. Be careful if you’re close to any other plants that you’d like to keep because these herbicides will take out the good with the bad.

Using Post-Emergent Herbicides Effectively and Safely

How to Use Post-Emergent Herbicides Safely 3

Now that you’ve chosen the proper herbicide for your situation, it is important that you get the job done properly. The good news is that the most effective way to apply your herbicides is also going to be the safest. Here are a few pro tips to keep in mind.

Study that label

Seriously. You may think you know what you should do, but read that label. It should tell you the proper technique for using your chosen herbicide for maximum effectiveness and also give you tips on how to avoid endangering any other plants or even your family or pets. You may have to peel back the label to get at the full information, but it’s worth the effort. Read it. Read it all.

Protect yourself

Wear gloves, long sleeves and pants, and even goggles if the label recommends it. Yeah, it may be warm or you may look goofy to the neighbors. It’s worth it to do the job right.

Know the weather

Is the rest of the day going to be hot and sunny? Rainy? Weather conditions can alter the effectiveness of your herbicides. Don’t forget to pay special attention to the wind. If the wind is blowing, leave your weed project for another day. The wind can spread your herbicide to places you don’t want it, like your rose bushes or neighbor’s yard.

Measure, measure, measure

Ever heard of the old saying, “Measure twice, cut once!” the same applies here. Know the area of ground you need to cover and just how much herbicide you need. You don’t want to over or underutilize your weed weapon.

Keep the area blocked off

If possible, block off the affected area with rope, tape, or some kind of marker. Since you read the label closely, you know how long you need to keep people and pets away. Let your family know what you’re doing and where, so they don’t have to guess. If it’s a large project, you may want to give your neighbors a heads-up as well. It’s the polite thing to do.

Pro Tips to Up Your Weed-Killing Game

Dealing with weeds in your lawn or garden isn’t fun. At best, it’s a nuisance. At its worst it can feel like an endless game of Whack-a-mole as the weeds pop up, you knock them down, and more pop up a few feet away.

Believe it or not, lawn care has come a long way in recent years. New techniques and new products can help bring your lawn up to date. Here are a few tips to help you get the job done as efficiently as possible.

Know your coverage area

Have you ever been applying herbicide and felt like, “Hey, I think I already did this part of the lawn.” It’s okay. We’ve all been there. The problem is that when you double cover you’re wasting your time, herbicide, and money. Luckily, you have better options.

Try using LawnStar Blue Spray Pattern Indicator or any other spray indicator when applying herbicides. These products mix with any herbicide to clearly mark where you’ve sprayed by coloring the turf blue. Don’t worry, the effects fade away in 24-48 hours. No more worrying about missing spots or wasting herbicide by over-applying.

Give your products a boost

What if you could make your post-emergent herbicide cover more ground, be more effective, and even have longer-lasting effects? This is where using a surfactant comes in.

You may not realize it, but a lot of the herbicide you are spraying is simply hitting its target, beading up and rolling off. It falls to the turf, useless. It’s not a flaw, it’s just nature.

Surfactants help any herbicide break through that barrier and adhere to the weed. The result is that you can use less herbicide, cover more ground, and see better results. Every time.

Surfactants like our LawnStar Non-Ionic Surfactant, are products that pay for themselves by maximizing the effectiveness of your herbicides.

Win the War on Weeds

Let’s face it, weed control is a constant battle. However, it’s one that you can win. By working smart and safe, you can have a lawn and garden that are safe and free of pesky weeds. If you have any questions, feel free to contact the experts at LawnStar.

Take pride in your lawn. There’s a new era in lawn care and you’re on the cutting edge.