How to Prevent Weeds with a Pre-Emergent Herbicide

I love my garden, but I do not love weeds! But honestly who does… If only our plants could grow as great as the weeds do right? But thankfully because of using a pre-emergent herbicide, the weeds are minimal and manageable.

A weed sprayer out in the garden

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Years ago I remember wanting to tear out my garden and never plant again because the weeds had grown so out of control!

Then the next garden season my dad cleared everything out with the tractor for a fresh start. Then I put down weed mesh with bark on top thinking it would be the ultimate solution for weed control…

Well, while it definitely helped, eventually the weed mesh started ripping and pieces were everywhere. It looked messy and my OCD self couldn’t handle it.

I wanted a garden without weeds and I wanted my pathways to look nice.

So that’s when I learned about spraying pre-emergent every year, and boy what an awesome day!

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What is a Pre-Emergent Herbicide

A pre-emergent herbicide prevents weeds from germinating or kills them on the spot as they start to germinate. Once applied, it will prevent future weed germination, usually for 4 – 12 months depending on the product.

Some pre-emergents such as Ortho Ground Clear will kill existing weeds and prevent future growth. This is what I like to use in my walkways and any areas where I will not be planting anything.

But most pre-emergents do not kill existing weeds, they just prevent future growth. So for best results, you should clear all of the weeds out first and then apply the pre-emergent.

In the video below I share some tools that I like using for clearing out weeds.

Must Have Tools for a Weed-Free Garden

There are also pre-emergent herbicides that are safe to use in your garden beds that will not affect the growth of your vegetables.

A couple of options include,

The two options above will not kill any existing weeds but they will prevent the growth of future weeds. They are safe to use in your garden beds but just be sure to read the directions for specific application notes and instructions.

When to Apply Pre-Emergent

For best results, herbicide applications should take place in early spring or fall. This is because different types of weeds are targeted at different times of the year.

For instance, in spring you will be preventing summer annual weeds such as crabgrass, knotweed, and spurge.

In the fall you’ll prevent winter annual weeds such as prickly lettuce, henbit, and common chickweed.

So I usually spray twice a year before each growing season.

The next important step for pre-emergent herbicide application is waiting just before a rain. Pre-emergent has to be incorporated into the soil for it to really be effective.

So it’s easiest to apply it just before a good rain or if there is no rain in the forecast you can still apply it but then be sure to water it in well with a sprinkler.

How to Apply Pre-Emergent

The easiest way to apply herbicide of any kind is with a hand sprayer or backpack sprayer.

I have a 2-gallon hand sprayer that can cover a pretty large area but the backpack sprayer is nice because it can hold more and is more convenient to carry.

Then depending on which herbicide you are using, check to label to figure out the exact amount of square feet that it will cover and the exact application instructions.

Where to Spray

Since pre-emergent prevents the growth of weed seeds, it can also mess up the germination of seeds you want to grow. That means you need to be extra careful to not apply it where you want to plant your vegetable or flower seeds.

But if you happen to apply it where you don’t want it, I’ll cover the solution below in the following section.

However, depending on the herbicide you choose, you may not have to worry. For example, Ortho Ground Clear will likely prevent the germination of all seeds that you do want to grow.

But this Vegetable and Ornamental Weeder and Preen Garden Weed Preventer, are not supposed to affect the germination of most vegetable seeds.

I spray all of my walkways between all of my garden beds, the entire perimeter of my garden, and around my chicken coop with Ortho Ground Clear, or a similar product. That is pretty much everywhere that I would spend my time pulling out weeds if they were growing.

So I save myself the time and hassle and spray it all!

Then if I need to use a product inside of my garden beds I use something safe for the germination of vegetables such as,

But just preventing weeds in the walkways and around the perimeter makes a huge difference. When I have weeds pop up inside of my garden beds it’s really easy to manage when I don’t have all of the weeds everywhere else.

My chicken coop and garden beds

What to Do if You Spray the Wrong Area

Don’t let the fear of spraying the wrong area scare you away from using pre-emergent.

First, pre-emergent needs to be incorporated with water to be effective. Second, if the ground gets disturbed before it gets incorporated then it will need to be reapplied.

So if you have sprayed an area that you decide to plant, all you need to do is disrupt the ground.

In the past, the way I have done this is by rototilling the ground to ensure I really disrupt and mix up the soil. But if you don’t have a rototiller just use a shovel and turn over the soil a few times.

The most important thing to realize is even though some pre-emergents can kill weeds for up to a year, it’s not 100% permanent.

You can always till up the area that was sprayed and plant it at any time.

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Why a Weed-Free Garden Makes My Life Better

Depending on how big your garden is, weeds may be more or less of an issue.

But no matter what, weeds are just a hassle.

I know for myself, not having to worry about weeds anywhere but inside my garden beds makes gardening so much more enjoyable.

Having weeds everywhere is overwhelming and takes up so much time that can be spent elsewhere.

There are days when I actually find it relaxing to sit on the side of my raised beds, pull out weeds, and simply enjoy my garden.

But when it’s over 100 degrees, weeds are ginormous, and the ground is hard, I do not find it so relaxing.

So my advice to any gardener is to use a pre-emergent so you can enjoy a “pretty much” weed-free garden!

Pin it for Later

A Hand Sprayer Filled With Pre Emergent Weed Killer

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  1. That’s good to know that you should apply the weed killer in the fall. I feel like that could help to stop any from growing through the rest fo the fall and the continuing to grow in the spring. I’ll have to consider getting someone to spread some of that down for me this fall so that I could avoid weeds next year.

    1. Yes applying it in fall before a rain works great for preventing all the weeds from growing the rest of the year. You can buy it in most garden centers. I like the ortho ground clear brand the best and I just spray it myself. At times Costco sells it and it’s the best deal I have found, but it’s seasonal there.

  2. Preventing weeds before its emergence will be a terrific job. Though I haven’t applied this before but after reading your article I believe it will work. However, what if we use a homemade weed killer? Will it works as pre-emergent?

    Keep up the good posting, Audrey.

    1. Hi! Pre-emergent is a life saver in the garden. It saves so much time. You do have to use a spray that actually prevents weeds though. Just a weed killer will kill existing weeds but will not prevent new weeds from coming up.

  3. I find it fascinating that you could use chemicals to prevent weeds from affecting your lawn! I heard stories that my uncle is planning to use his backyard as a small vegetable farm. I should tell him about the benefits of weed control in the future.

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