Types of Pre-Emergent Herbicides 

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Tall weeds growing above grass in a yard

Want to keep crabgrass from making you crabby? Want to nip other weeds in the bud? 

When it comes to keeping weeds from sprouting in your yard, pre-emergent herbicides are your best defense, but which type is pre-emergent is right for you and the weeds you find in your yard?

There are two different types of pre-emergent herbicides, granular and liquid, and each can either be organic or synthetic. You also can choose to apply a selective pre-emergent (targeting a specific weed) or non-selective pre-emergent (deterring all sorts of weeds). 

In this article, we’ll cover the different types of pre-emergent herbicides to help you to choose the right one for your yard.

Liquid pre-emergent herbicides

Liquid pre-emergent herbicides are easier and quicker to apply than granular pre-emergents. Pre-emergent herbicides are recommended for full coverage over a large area. 

Advantages:

  • Liquid pre-emergents lets you be more precise in your application (cracks in a driveway or sidewalk, for example).  
  • Pre-emergents require less water to work. 
  • Liquid pre-emergents are faster working than granular pre-emergents. 
  • You can use less of the pre-emergent herbicide, saving you time and money. 

Disadvantages:

  • You must follow specific measurements, which may be challenging for people who aren’t familiar with these chemicals.
  • Harder to apply in smaller areas, especially in areas where there is grass you want to avoid spraying. 
  • Liquid pre-emergents take more prep time than granular herbicides. 

Pro Tip: When choosing a liquid pre-emergent for your lawn, note that more concentrated liquid formulas can be extremely strong. Use these concentrated formulas with caution if you’re applying them to a smaller space. 

Bottom line: For a precise, affordable, and even application of your pre-emergent herbicide, liquid formulas are your best bet. 

Granular pre-emergent herbicides

Granular pre-emergent herbicides involve less prep time but require a bit more effort (purchasing a spreader) and time (slower to act) than liquid pre-emergents, so they are not as commonly used. 

Advantages:

  • Involve little mixing or measuring.
  • Easier to spread
  • Label usually makes it easy to determine how many square feet the herbicide will cover 

Disadvantages:

  • Hard to distribute evenly
  • Require more water
  • Tend to work slower than liquid formulas

Bottom line: Granular pre-emergents are usually recommended for smaller lawns, as the disadvantages become less of an issue in limited areas.

Pro Tip: Granular pre-emergents with smaller particles are easier to spread evenly

Synthetic pre-emergent herbicides

Synthetic herbicides, also known as non-organic herbicides, are chemically designed to kill weeds. Some of the active ingredients found in synthetic herbicides include oxadiazon, dithiopyr, and prodiamine.

Synthetic pre-emergents are best if these weeds are a problem in your yard: broadleaves, bramble, and traditional and ornamental grasses.

Advantage:

  • Chemical pre-emergents need to be reviewed and tested by the EPA
  • More easily available 
  • Fast acting
  • More affordable 

Disadvantages:

  • Can harm the environment 
  • Can affect the fertility of your soil

Pro Tip: Be careful when applying these chemical solutions on your lawn. Follow label instructions to keep children and pets away from where you have applied your pre-emergent herbicide for the time frame specified.

Common chemicals in synthetic pre-emergent herbicides 

The chemicals used in your synthetic pre-emergent herbicides matter, and as each chemical works better on different types of weeds. 

Some contain Prodiamine, which can prevent weeds like chickweed or dandelion, while others with Dithiopyr can prevent goosegrass. 

Common ingredients found in pre-emergents include: 

  • Prodiamine: Prevents grassy and broadleaf weeds like chickweed, witchgrass, clover, thistle, crabgrass, creeping bentgrass, and dandelion. Prodiamine struggles to control nutsedge. 
  • Dithiopyr: Prevents chickweed, oxalis, clovers, dandelion, bittercress, crabgrass, goosegrass, and annual bluegrass. Dithiopyr has a tough time controlling spurge and broadleaf weeds. 
  • Benefin (aka Benfluralin): Prevents crabgrass, ryegrass, carpetweed, chickweed, annual bluegrass, sandbur, pigweeds, foxtails, goosegrass, and knotweed. 
  • Trifluralin: Prevents Summer grass, annual bluegrass, chickweed, redroot, and red-dead nettle. Trifluralin isn’t your best choice if you are trying to prevent thistle, clover, daisies, and wild turnip. 
  • Isoxaben: Prevents dandelion, thistle, clover, chickweed. Not your best bet for controlling grassy weeds like crabgrass, annual ryegrass, and carpetgrass. 
  • Oxadiazon: Prevents crabgrass, clover, dandelion, thistle, and knotweed. There are better options to prevent chickweed, spurge, and pearlwort. 

A pre-emergent herbicide can contain one or multiple of these ingredients, and choosing one can also depend on if the herbicide is a selective or non-selective herbicide as well. 

Organic pre-emergent herbicides

There are many types of organic pre-emergents, including vinegar and corn gluten. Corn gluten has become the most common alternative to chemical pre-emergent weed control because it works to prevent weeds and it is a rich addition to your soil.

Organic pre-emergents are best if these weeds are a problem in your yard: Crabgrass, clover, and dandelions.

Advantages:

  • Great for your soil. Corn gluten has a high amount of nitrogen, and as the nitrogen is released over a few months, it works to prevent any weeds from growing.
  • Non-harmful to the environment

Disadvantages:

  • Can attract bugs 
  • Slow to release 
  • Can be more expensive 

Pro Tip: You may need to mow your grass before applying some pre-emergent herbicides. Check the label of your herbicide. 

Selective pre-emergent herbicides

Selective herbicides target only specific weeds, so they are safe to use in areas with other plants and grasses. If only one type of weed grows in your yard — or a few types — look for a pre-emergent herbicide that can block that weed from growing. 

For example, selective pre-emergents are a great choice if you want to prevent broadleaf weeds in your flower or vegetable garden without killing the other plants. 

Non-selective pre-emergent herbicides

Non-selective herbicides will kill all manner of weeds — and your grass, flowers, and vegetables, too. For this reason, use a steady hand when you apply a non-selective herbicide. 

Non-selective pre-emergents work best if you want to prevent all types of weeds, plants, and grasses in a localized area, like a driveway. 

Pro Tip: Some non-selective herbicides can be used as both a pre and post-emergent, so make sure to check the product when making your purchase. 

How to choose the best pre-emergent herbicide for your lawn

Pre-emergents are not one size fits all for every lawn. From the difference in the way you apply granular and liquid formulas to the wide range of ingredients found in each herbicide, it can take some digging to find the right type for your yard. 

The best ways to choose a pre-emergent herbicide is based on: 

  • The size of your lawn
  • The kinds of weeds you have
  • The amount of prep-time time you have
  • Whether you require organic options 

Once you’ve answered these questions, you can whittle down the many options of pre-emergent herbicides to find the best one for your yard. 

So what’s next? 

You’ll need to know when and how to apply pre-emergent herbicides. A couple of tips? The best time to apply your pre-emergent herbicide depends on the season and even the ground temperature. 

If all else fails and you’re still not sure what type of pre-emergent herbicide is best for your yard, or you would rather not deal with the application yourself, a Lawn Love lawn care pro near you can take care of all of that for you. 

After all, that’s what we do. Lawn Love makes lawn care easy.

Main Photo Credit: Hello I’m Nik | Unsplash

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