Best Pre-Emergents for Weed Prevention

Best Pre-Emergents To Prevent Weeds
In the US there are a number of different products designed for residential home-owners to prevent weeds from sprouting in the Spring and taking over your yard in the summer. The most common types of products that prevent weeds from germinating are collectively called weed pre-emergents and the best pre-emergents for lawns tend to be the cheapest ones. The trick however is getting them applied to your lawn at the right time of year.

Before I cover the best options available to homeowners let’s first list all of the options and then narrow it down a bit.

To stop most grassy weeds from overwhelming your grass you should apply one of the following active ingredients which are used in various brands of pre-emergent weed preventers.

  • 1. Pendamethalin
  • 2. Dithiopyr
  • 3. Prodiamine
  • 4. Mesotrione
  • 5. Corn Gluten Meal

Here’s a video where I present my typical weed prevention strategy. This will apply to most people living in most locations growing the most common grass types.

Now with that out of the way let’s start diving into the most common questions I get about weed pre-emergent products.

Which Pre-Emergent Will Prevent Weeds Best or Longest?

Generally speaking Prodiamine will prevent most residential weeds for a reasonable cost. It can easily be found in granular form which makes it easier for most people to apply it to a lawn space. It is very effective in both cold and warm season geographies and on commonly found cold and warm season grass types.

Below are the best pre-emergent products available for the prevention of grassy and broadleaf weeds. Many of these products are applied in the early Spring to prevent weeds from becoming a problem by summer while others are applied at the end of summer to prevent the germination of fall weeds that typically become a problem near the end of winter.

First I’ll list the most common products used in lawns across America and then I’ll list the best pre-emergent options for different grass types as well as for different usage situations.

FYI – If you have a lawn and don’t know how to make it look it’s best then take a look here for my free “Don’t Know Where To Start” series.

The Most Common Pre-Emergents Applied To Lawns

The vast majority of pre-emergent weed preventers purchased by home-owners use one of 3-4 different active ingredients: Pendimethalin, Dithiopyr, Prodiamine, and Mesotrione. Below I’ve listed my personal recommendations for each of these products:

1. Pendimethalin

Pendimethalin usually has a shorter duration of effectiveness so it’s great for northern climates that may have a shorter growing season, especially those lawns that need to be overseeded in the late summer going into Fall.

Products That Use Pendimethalin

♦ Scotts Halts Crabgrass & Grassy Weed Preventer – Amazon
♦ Pendulum 2G – Amazon | DoMyOwn

2. Dithiopyr

This is a shorter lived pre-emergent that loses it’s effectiveness after only a few months time but the active ingredient has some minor post-emergent effects on young crabgrass that germinated within the preceding 3-4 weeks prior to application. This makes this product particularly useful for applying to a lawn multiple weeks too late.

Products That Use Dithiopyr

♦ Howard Johnsons Dimension 0.27G – DoMyOwn
♦ Hi-Yield Weed and Grass Stopper – DoMyOwn | Amazon
♦ Sunnyland 0-0-7 w/ Dithiopyr – Yard Mastery | Amazon
♦ Anderson’s 18-0-4 Dimension – Amazon
♦ Ferti-Lome 20-0-3 Crabgrass Preventer – DoMyOwn
♦ Bonide DuraTurf Crabgrass and Weed Preventer – DoMyOwn

3. Prodimaine

This is a liquid prodiamine that is a generic version of the popular Barricade herbicide. It is sold on Yard Mastery’s marketplace and is notably cheaper than buying the name brand stuff on Amazon. You can price it out and buy in through this link:

Alternatively, you can get a granular Prodiamine packaged with 7% potassium fertilizer for bit of weed suppression and a boost in turf health with Yard Mastery’s 0-0-7 Prodiamine .38%. You can pick that up through this link.

4. Mesotrione

Mesotrione is an ingredient that doesn’t exactly prevent germination and rooting like the other alternatives on this list. Instead this product blocks photosynthesis in target weeds so when they germinate the first leaves start forming but can’t transform sunlight into energy for growth and the plants end up dying. Nearly all grass types will grow unaffected by Mesotrione except for Zoysia, Bermuda, Fine Fescue, Seashore Paspalem, and Kikuyu so this should only be used by individuals who know what their grass type is in the first place.

The ingredient can be absorbed by plant roots or foliage. Root uptake will provide post-emergent effects on a minority of weeds while pre-emergent effects will prevent the development of a greater number of weeds…but only for 20-30 days.

For good mid-term prevention of weeds Mesotrione should be applied every third week for approximately three rounds giving you roughly 2 months of prevention in a single season.

The most obvious reason to use Tenacity is if you are seeding a new lawn or overseeding an existing lawn.

Products That Use Mesotrione

♦ Meso 4SC Select – Yard Mastery | Amazon
♦ Tenacity – DoMyOwn | Amazon
♦ Liquid Harvest Mesotrione – Amazon
♦ Torocity Mesotrione – Amazon

5. Corn Gluten Meal

Corn gluten meal is a byproduct of corn processing. It is a strictly natural source of Nitrogen and can be used in a lawn without worry of the application of chemicals. The meal is known to slightly suppress seed germination in certain conditions mostly surrounding soil moisture. Although it doesn’t give exceptional pre-emergent efficacy it can be used as a regular Spring fertilizer due to its naturally high Nitrogen content and if any weeds are prevented then that is a great side-effect of this product.

Products That Use Corn Gluten Meal

♦ Lawnbright’s Weed Wipeout – Lawnbright
♦ Jonathan Green CGM – Yard Mastery | Amazon
♦ Espoma Organic Weed Preventer – DoMyOwn | Amazon