Weeds can ruin the look of an otherwise healthy lawn. They also — more often than not — seem to appear overnight.
If you want a truly weed-free lawn, one of the best things you can do is to stop weed seeds before they sprout. And the easiest way to achieve that is by applying a preventative herbicide at least once per year.
Pre-emergent herbicides are extremely effective products that kill off weeds when they are still seedlings. As with all lawn care chemicals, however, not all herbicides are created equal.
In this article, I’ll explain the different types of herbicides and how they work. I’ve also selected some of the best pre-emergent herbicides for lawns so you can start controlling weeds as soon as possible.
- Top Pre-Emergents for Turf Grass
- What Is a Pre-Emergent Herbicide?
- Choosing A Preventative Herbicide
- 8 Best Pre-Emergent Weed Killers Reviewed
- 1. Quali-Pro Prodiamine Pre-Emergent Herbicide
- 2. Andersons Barricade Pre-Emergent Weed Control
- 3. Ace Crabgrass Preventer and Fertilizer For All Grass
- 4. Scotts Crabgrass Preventer Lawn Fertilizer For Multiple Grass Types
- 5. Hi-Yield Fertilome Turf & Ornamental Weed Stopper
- 6. Scotts WeedEx Crabgrass Preventer Pre-Emergent Weed Control
- 7. Bonide Pre-Emergent Crabgrass & Weed Preventer For Lawns
- 8. Southern Ag Atrazine Grass Weed Killer
- Applying Pre-Emergent Herbicide
- Verdict: Best Preventative Herbicide for Lawns
- FAQs Preventing Weeds In Lawns
Top Pre-Emergents for Turf Grass
Those weeds won’t take care of themselves. If you’re short on time but still interested in the most effective weed prevention treatments around, check out my top recommendations here:
Best Pre-Emergent Spray
Quali-Pro Prodiamine Pre-Emergent
Powerful liquid weed preventer that will stop seed germination of most weeds. Suitable for use on most turf grass.
Best For Broadcasting
Andersons Barricade Pre-Emergent
A granular pre-emergent ideal for broadcasting on larger lawns. Prevents most weeds, and is suitable for use on most turf varieties.
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What Is a Pre-Emergent Herbicide?
According to the US EPA, an herbicide is any chemical used to control the growth of undesirable plant life. Pre-emergent herbicides are chemicals that interfere with seed germination or kill off seedling root tissue as soon as it grows. Some companies advertise these products as weed preventers.
Again, these herbicides are used to prevent the growth of new weeds. They will have no effect on existing weeds in your lawn or garden. Chemicals that target mature weeds — e.g., Roundup — are instead known as post-emergent herbicides.
Pre-emergent formulas can be used in lawns, gardens, and all other types of landscapes. However, these herbicides can also interfere with the seeds of desirable plants, including vegetables and flowering ornamentals.
Choosing A Preventative Herbicide
Applying a pre-emergent herbicide is one of my favorite ways to maintain a weed-free lawn. While no preventative measure is 100% effective against new weeds, the right formula can have a massive impact on the number of weeds that invade your lawn versus untreated years.
As with all lawn chemicals, I don’t recommend using just any herbicide. Several factors determine which active ingredient and formulation will produce the safest and most effective results for your lawn.
Before I go into my favorite herbicides currently on the market, I want to break down some of these factors so you feel more equipped to choose the best weed preventer for your needs.
Grass Type
Since pre-emergents target plants at their seed or seedlings stages, these products are generally safe to apply to all perennial turf grasses. Annual or biennial grasses that are expected to reseed themselves should not be treated with such herbicides.
To be safe, I strongly suggest checking all herbicide labels to ensure the active ingredient is compatible with your lawn’s grass type.
Type Of Weeds To Prevent
Not all herbicides are effective against all weed species. To achieve the best results from any chemical herbicide, you should always identify the weeds plaguing your lawn beforehand.
If you can’t pinpoint the exact species growing in your lawn, determining whether the weeds are categorized as grassy or broadleaf will make accurately selecting an herbicide much easier.
Ideally, you should find a formula that targets all of the weeds you’d like to prevent. If this isn’t possible, however, there are ways to combine different products to get the results you want. I recommend reaching out to a professional landscaper or local Extension Office for tips on doing this safely.
Selective or Non-Selective Herbicide
Along with identifying the exact weeds you want to treat against, you should know whether the herbicide you plan to use is categorized as selective or non-selective.
Selective herbicides only work on some weed species. These are a great choice when treating against a handful of common weeds or when you want to ensure desirable plants in your landscape remain unaffected.
Non-selective herbicides paint the treated area with a wide, unbiased brush. Nearly all plants will be affected by these chemicals. A non-selective formula is generally ideal when treating many species at once or when the weed in question is resistant to selective formulas.
Size of Lawn and Your Available Time
In my experience, some formulas are better suited to specific property types than others. You may have an easier time with a particular herbicide depending on your lawn’s size and the equipment you have access to.
Personally, I prefer to use granular herbicides on my lawn due to its moderate size. It would take far too long to evenly distribute a liquid formula over the same area.
There are other reasons to take your available time into account when choosing a herbicide. For example, granular herbicides must be activated with water to work. This means you need to allow time to irrigate the entire treated area after the herbicide is applied. Liquid herbicides don’t require this extra step.
Application – Granule Vs Spray
In terms of application, choosing between a granular or a spray formula is partially a personal preference. Some homeowners just prefer to work with one option versus the other.
Sprays can be applied using a number of methods. The most efficient options, however, require special equipment that you may or may not already own. I recommend investing in a quality pump or backpack weed sprayer at the very least if you plan to spray herbicide over a large area.
Granular herbicides can be spread by hand or with a walk-behind broadcaster. While I apply granules to my garden beds using a shakeable container, I prefer to use a broadcast spreader for my lawn. You can purchase a quality broadcast spreader for relatively little money that can also be used to efficiently sow grass seed and apply dry fertilizers.
Herbicide or Weed and Feed
Many lawn fertilizers also include pre-emergents. If you can find a formula that meets both of your lawn’s needs, you can easily take care of two chores at one time.
Herbicide alone can be used any time weed seeds are present in the soil. Weed and feed products cannot be used year-round on most lawns without triggering unseasonable growth. To get the most from your weed prevention routine, I recommend keeping a non-fertilizer herbicide on hand for applications during these off-times.
8 Best Pre-Emergent Weed Killers Reviewed
I’m well aware of how intimidating it is to shop for herbicides when you’re not 100% confident in the selection process. To help you save time and put your mind at ease, I’ve reviewed some of the best formulas available and explained why I think they deserve a spot in your lawn care regimen.
1. Quali-Pro Prodiamine Pre-Emergent Herbicide
Best Pre-Emergent Spray
- Ingredients: Prodiamine
- Weeds: All common weeds
- Application: Sprayer
- Formulation: Liquid Concentrate
- Action time: Up to 8 months
- Rainproof: Yes
- Coverage: ~20,000 sq. ft.
- Use: All Grass Types Except Bentgrass
This product from Quali-Pro is a powerful option for nearly all turf grasses. A single bottle of this liquid concentrate will go a very long way in keeping your lawn weed-free.
The active ingredient, prodiamine, is safe to use in residential lawns as well as ornamental landscape beds. I do not, however, recommend using this product in beds where consumable fruit or vegetables are being grown.
You’ll see the best results applying this herbicide before weed seeds actually germinate. Note that it must also be activated with either light rainfall or by watering the area within 14 days of application.
One thing I really like about this particular formula is that it can be mixed with other water-soluble or concentrated products such as fertilizer in the same tank. This allows you to treat your lawn for a variety of things in a single step.
Use On: Poa annua, Henbit, Knotweed, Chickweed, Spurge, Foxtail, Goosegrass, and many other common lawn weeds.
2. Andersons Barricade Pre-Emergent Weed Control
Best For Broadcasting
- Ingredients: Prodiamine
- Weeds: All common weeds
- Application: Broadcast Spreader
- Formulation: Granular
- Action time: Up to 8 weeks
- Rainproof: Yes
- Coverage: 10,000 sq. ft.
- Use: All Grass Types
This herbicide contains the same active ingredient as the formula above but in a granular format. I highly recommend this product if you have a large area in need of treatment or would simply prefer to use a broadcast spreader for application purposes.
The Andersons’ Barricade formula targets over 30 common lawn and garden weeds as they germinate and sprout. It is advertised specifically for the control of crabgrass but that is far from its only use.
Based on my research and own experience, this pre-emergent herbicide is safe to use on all popular turf types. However, take note that some grass varieties will respond poorly to high amounts of this product. Check the label for the maximum recommended dose for each grass species.
Use On: Crabgrass, Poa annua, Goosegrass, Henbit, Foxtails, Chickweed, and most other lawn weeds.
3. Ace Crabgrass Preventer and Fertilizer For All Grass
Best Weed and Feed Type
- Ingredients: Pendimethalin
- Weeds: Crabgrass, and other grassy weeds
- Application: Broadcast Spreader
- Formulation: Granular
- Action time: Up to 4 months
- Rainproof: Yes
- Coverage: 15,000 sq. ft.
- Use: All Grass Types Except Bentgrass
I’m all about checking off as many things on my lawn care to-do list at once as I possibly can. (After all, it leaves more free time to work in my garden beds.) So I’m very likely to reach for a weed and feed product like this formula from Ace Hardware.
This is another product that, at first glance, appears to be intended for crabgrass control. However, the active ingredient is effective against dozens of common grassy and broadleaf weeds.
In optimal conditions, this formula can remain active in the soil for about 4 months. Keep this in mind if you plan to distribute any type of seed within the area in the near future. Also, I don’t recommend this product for use on bentgrass species.
- Ingredients: Pendimethalin
- Weeds: Crabgrass, and other grassy weeds
- Application: Broadcast Spreader
- Formulation: Granular
- Action time: Up to 4 months
- Rainproof: Yes
- Coverage: 5,000 sq. ft.
- Use: All Grass Types Except Bentgrass
If you don’t have access to an Ace Hardware store or would prefer to use a more established brand, this Scotts Crabgrass Preventer is extremely similar to the formula I recommended above.
Again, you can use this herbicide on far more than just crabgrass. It controls 9 of the most prevalent lawn weeds while also delivering vital nutrients to the soil.
The fertilizer portion of this product has a nutrient ratio of 30-0-4. In my experience, this ratio will meet the needs of most established lawns when applied early in the growing season. The manufacturer recommends applying this weed and feed product as often as every 3 to 4 mows for season-long weed prevention.
- Ingredients: Dithiopyr
- Weeds: Most Lawn Weeds
- Application: Broadcast Spreader
- Formulation: Granular
- Action time: 2 to 4 months
- Rainproof: Yes
- Coverage: 5,000 sq. ft.
- Use: See list of grass types below
Grass Types: Creeping Bentgrass, Kentucky Bluegrass, Fescue, Ryegrass, Zoysiagrass, Centipedegrass, Buffalograss, Bermudagrass, Bahiagrass, Carpetgrass, and St. Augustine
While there are definitely times when your lawn and garden call for different products, there’s little reason to invest in a separate pre-emergent for each area. If you’re looking for a product that is safe to use throughout your entire landscape, I highly recommend this granular formula from Hi-Yield.
This herbicide controls or suppresses 40 weed species, including crabgrass. The active ingredient — dithiopyr — is effective against crabgrass seeds up to 4 weeks later than other herbicides.
While some herbicide labels leave much to be desired, I really appreciate the amount of detail this one provides. In addition to a list of targeted weed species, each package includes a precise list of ornamental plants that have proven resistance against the active ingredient. There’s no need to guess which ornamentals are vulnerable to this herbicide.
Use On: Crabgrass, Foxtail, Wild Oats, Chickweed, Henbit, Knotweed, Spurge, and Others
- Ingredients: Pendimethalin
- Weeds: Most common lawn weeds
- Application: Broadcast Spreader
- Formulation: Granular
- Action time: Up to 4 months
- Rainproof: Yes
- Coverage: 5,000 sq. ft.
- Use: All Grass Types Except Bentgrass
If your interest was piqued by the Scotts weed and feed I recommended above but you already have a trusted fertilizer routine, this formula is a great alternative. It’s a dedicated herbicide with the same active ingredient.
This herbicide holds up against snow, rain, and freezing temperatures, so you can confidently apply it early in the year without worrying about lost efficacy. I’m sure I’m not the only one who encounters unpredictable weather throughout spring.
I recommend using this formula in the spring and fall for year-round weed control. It can be safely combined with other Scotts lawn products per the label.
- Ingredients: Dithiopyr
- Weeds: Chickweed, Crabgrass, Henbit, Knotweed, Goosegrass, Spurge, and Others
- Application: Broadcast Spreader
- Formulation: Granular
- Action time: 2 to 4 months
- Rainproof: Yes
- Coverage: 5,000 sq. ft.
- Use: See list of grass types below
Grass Types: Creeping Bentgrass, Kentucky Bluegrass, Fescue, Ryegrass, Zoysiagrass, Centipedegrass, Buffalograss, Bermudagrass, Bahiagrass, Carpetgrass, and St. Augustine
This preventative herbicide targets a number of persistent lawn and garden weeds. It’s formulated with the active ingredient dithiopyr, which works on crabgrass seeds up to 4 weeks after they germinate. (Pre-germination applications are still required for the control of other weed varieties.)
In addition to crabgrass, this product controls common species like chickweed, henbit, and spurge. It’s safe to use on most turf grasses and ornamental shrubs — you can find a detailed list of recommended applications on the product label.
When used as directed, you can apply this herbicide within weeks of planting grass seed. It is also safe to use with other herbicidal products as long as you wait 4 weeks between each application.
- Ingredients: Atrazine
- Weeds: Poa annua, Chickweed, Crabgrass, Henbit, Knotweed, and Others
- Application: Sprayer
- Formulation: Water soluble
- Action time: Up to 6 months
- Rainproof: Yes
- Coverage: 3,720 sq. ft.
- Use: St. Augustine Grass and Centipede Grass
One of my favorite pre-emergent herbicides for St. Augustine and centipede grass lawns is this water-soluble formula from Southern Ag. It is highly effective against grassy and broadleaf weeds like crabgrass, knotweed, and annual bluegrass.
I don’t recommend applying this product with a hose-end sprayer. Instead, you’ll want to invest in a wearable or handheld sprayer for the best results.
The active ingredient atrazine is unique in that it works as both a pre-and post-emergent herbicide. The only downside, at least in my opinion, is that this chemical is only safe to use on a couple of turf types.
Applying Pre-Emergent Herbicide
There are two pieces of information I think everyone should know before touching any type of weed preventer:
- These treatments must be active in the soil when weed seeds are germinating to be effective
- Treatments present in the soil can and do interfere with the germination of desired seeds
Keeping these things in mind will help you troubleshoot some of the most commonly encountered problems when applying pre-emergent herbicides.
When to Apply Pre-Emergent
Ideally, a preventative herbicide should be applied within 14 days of weed seed germination. You want to allow just enough time for the product to penetrate the soil and activate before the seeds begin sprouting.
In my own lawn, applying preventative herbicides in the spring and fall produces the best results. The ideal schedule for your region may vary.
Do not apply these herbicides in areas you plan to seed or have recently seeded. In my experience, the average waiting period required for successful germination is about 4 months. Check your product label for exact details on how long to wait before and after seeding.
Regional Climate and Grass Dormancy
Generally speaking, you should apply preventative herbicides when the surface soil temperature is consistently around 55°F. This may vary per formula, so check your individual herbicide’s packaging for details.
For the best results, I recommend learning when weed seeds typically sprout in your area. Local resources — i.e., gardening neighbors — can be extremely helpful if you don’t know this information yourself.
Keep in mind that you may need to apply pre-emergents before your turf grass is actively growing. Some weeds may emerge before your lawn leaves its own winter dormancy.
When Is It Too Late To Use Weed Preventers?
If you can already see problem weeds growing in your lawn, it’s generally too late for the herbicide to be effective. This isn’t the case for weed species that germinate continuously throughout the year.
If you’re unsure when to apply herbicide for the best control in your area, I suggest erring on the side of applying too early. Many formulas remain active in the soil for 3 months or longer and will be effective even if you jump the gun by a couple of weeks.
How to Apply Pre-Emergent on Lawns
Liquid herbicides are typically applied using some type of sprayer. Hose-end sprayer attachments are great for small projects. If you have a large section of lawn to treat, however, I suggest investing in a handheld- or backpack-style sprayer.
My preferred application method for granular herbicides is a broadcast spreader. A walk-behind spreader will suffice for most projects. For particularly large properties, you can also use a pull-behind spreader attached to a riding lawn mower.
Calculating How Much Herbicide You Need to Apply
All herbicides I am familiar with provide clear instructions for how much product to apply to a given area. You can find these guidelines on the product label of your chosen herbicide.
Oftentimes, these application guidelines are provided per 1,000 square feet or a similar measurement. So knowing the general size of your lawn (or the area to be treated) is essential to determining how much product you’ll need overall.
Also, pay close attention to the provided broadcast spreader or hose sprayer settings to ensure you’re applying the right amount of herbicide to your lawn.
How Often to Apply Preventative Weed Killer
If you’re new to herbicides, I suggest starting with one or two applications per year and seeing how your lawn responds. You can adjust this schedule in future years until you achieve the desired results.
Each herbicide typically comes with a recommended application schedule. I strongly suggest reading the label of any chosen herbicide to learn more about application frequency. You may also find that there is a maximum number of applications you should make within a calendar year to maintain lawn health and soil quality.
Verdict: Best Preventative Herbicide for Lawns
I’m a true believer in the power of preventative weed control. If I could only pick one method to minimize weeds in my own yard, it would be applying one of the products recommended here.
Best Pre-Emergent Spray
Quali-Pro Prodiamine Pre-Emergent
Powerful liquid weed preventer that will stop seed germination of most common weeds including Henbit, Chickweed, and Spurge. Suitable for use on most turf grasses other than Bentgrass.
For smaller areas that can be easily treated with a sprayer, I strongly suggest a product like Quali-Pro Prodiamine Pre-Emergent Herbicide. This potent liquid concentrate will last for several years in most cases and can be mixed with other treatments for quick results.
Best For Broadcasting
Andersons Barricade Pre-Emergent
A granular pre-emergent herbicide that’s ideal for larger lawn areas when administered with a broadcast spreader. Prevent most weeds, especially Crabgrass, and is suitable for use on most turf varieties.
If you’d prefer a granular formula, then Andersons Barricade Pre-Emergent Weed Control is my top recommendation. It targets a variety of common weeds and is safe to use on nearly all turf types.