Scotts Step 3 vs. Summer Guard: (differences & how to use)

What is the difference between Scotts Step 3 and SummarGuard?

The major difference is Scotts Step 3 is an improved formula, which allows up to 2X more powerful dandelion and easier clover control, while is ideal when you’re looking to strengthen your lawn against external attacks such as heat, drought, bugs (e.g., armyworms), and Summerguard doesn’t burn lawn.

Recently, I was asked about the differences between Scotts step 3 and Summerguard by a new student in our Slow Gardening Program. Many people are confused as to what they are, how they work, which one is better, and why? Well, here we go.

First, you need to understand that both of these products work exactly the same way and produce the same results. They just use different active ingredients.

Step3 has two different fungicides, Daconil 2787 and chlorothalonil. The first is good at killing certain leaf spots whereas the second can control rust, dollar spot, brown patch & others. Alone neither will control every pathogen that might infect your lawn but combined they are pretty good.


SummerGuard by Bonide is a post-emergent selective control for certain broadleaf weeds in bermudagrass lawns that kills existing weeds and prevents new ones from growing by inhibiting an enzyme necessary for plant growth.

It will not harm desirable plants, pets or people once dry and does not affect moles or gophers, who feed on the weeds.

Read Also:- Nitro Phos vs Scotts – which is better for your Lawn?

Quick Facts:

To help stop the spread of fungal leaf diseases, SummerGuard contains a combination of chlorothalonil and mancozeb. These active ingredients have been proven to be extremely effective in the fight against powdery mildew, brown patch, rust, and other fungi associated with turfgrass disease. 

In addition, sulfur has been added to reduce the growth of moss and improve overall appearance by developing a deep green color on lawns.

The final active ingredient in this disease-fighting formula is dithiopyr, which provides long-term preemergence control of annual bluegrass and many other grassy weeds that cause thinning or weakening of your lawn.

Step 3 combines two fungicides (chlorothalonil and diaconal) with nitrogen to promote healthy roots and lush green growth. This product prevents damage from many diseases, such as brown patches, that can quickly kill your lawn. It will also help control grubs and some other insects that feed on grass roots.

When to use Scotts Step3:

Step 3 is a pre-emergent herbicide that must be applied prior to weed seed germination and should only be used when the soil temperature is below 80°F [21°C].  For best results apply no later than 2 weeks before a rainfall event, or watering is expected.  

To achieve optimum control of crabgrass, broadleaf weeds, and other listed annual grassy and broadleaf weeds, apply during April through August (above 50°F/10°C) for one application; May through July (above 70°F/21°C) for two applications. Apply again every 4 months as needed.

Read Also:- When To Apply Scotts Step 4 (Application Guide)

Thus, if you had persistent weeds over the winter or in early spring, you would apply Scotts Step 3 three times during the summer.

When to use SummerGuard:

SummerGuard by Bonide is best applied when temperatures are between 45°F/7°C and 85°F/29°C.  Use in fall, winter, and spring to selectively control broadleaf weeds like clover, dandelion, ground ivy, henbit, etc.

Summerguard does not harm desirable plants or pets; it is also safe for kids & pets once dry.  It will not affect moles or gophers who feed on the weeds that are killed by summer guard.

How much do I need?

Step 3 (SST) requires a minimum turf/landscape area of 9,000 square feet to be effective.  Smaller areas can be covered by adding water and using a hand-pump sprayer or similar device.

For weeds with taproots like dandelions, you will need 20 ounces per 1,000 sq ft (the bottle has a built-in measuring cup).

SummerGuard requires 3 oz per 1,000 sq ft for optimum weed control.

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Contains the same active ingredient: Prodiamine 40% (4 lb per 100 gals), these products are selective; they kill certain broadleaf plants and not others including grasses and other desirable foliage. 

Both Step 3 and Summerguard require watering within 2 days after application. Both are safe to water in after 24 hours.


Scotts Step3 is only available in an 18 oz bottle, while Summerguard is sold in a concentrated form that requires mixing with water before use. 

Step 3 comes with built-in measuring cups making it easy to apply the right amount for your yard size or desired coverage area. 

Summerguard must be measured out carefully prior to each use, this can easily lead to under-usage resulting in inadequate control of weeds.  

This is especially true if you have a larger lawn or bigger weed problem, and will require purchasing separate measuring devices which means more cost at the end of the day. Scotts contains atrazine (and related compounds) which kills certain aquatic organisms  Summerguard does not contain any aquatic toxins.


Is one better than the other?

Scotts Step 3 is a pre-emergent herbicide that helps kill existing weeds and prevent new ones from growing.  It can be applied as early as 2 weeks before weed seed germination, but should only be used when the soil temperature is below 80°F [21°C]. 

Scotts is costlier to use since it comes in an 18 oz bottle for coverage of up to 9,000 square feet and must be applied three times during the summer:

May through July (above 70°F/21°C) and also two more applications 4 months apart.  If you have persistent weeds over the winter or in early spring, you may need to use Scotts Step 3 5 times per year.  This increases the cost of using this product and makes it more difficult to apply as well.

SummerGuard is a selective broadleaf weed killer which can be applied no earlier than mid-April and as late as September (weather permitting).  It does not harm desirable plants or grasses, dogs, and kids once dry.

It kills certain broadleaf weeds like dandelions, clover, etc by inhibiting photosynthesis that occurs at the cellular level without affecting other plants such as grasses and landscape shrubs. 

 It’s important to water it within 2 days after the application for optimum control of weeds; Summerguard will not damage your grass after 2 days.  It can be mixed with water before usage or purchased as a concentrate.

So, which is better? 

Unfortunately, there is no easy answer to this question.  In my opinion, Summerguard is preferred since it contains Prodiamine (40%) which kills certain broadleaf weeds without harming landscape plants and grasses.  

It’s also safe for kids and pets once dry. SummerGuard requires watering within 2 days after application to ensure maximum weed control, but you’ll have to do the math on how much of the concentrated solution you need to mix depending on your lawn size/ number of weeds as well as weather conditions that might affect absorption into the soil such as high temperatures (>85°F, >30°C).

Summerguard has a 3-4 month residual effect in the soil so you won’t have to apply it more than twice or three times per season. 

Read Also:- The Grow Bag Size Chart For Vegetables (2023)

The 18 oz bottle size of Scotts Step3 makes it harder to apply for large lawns and big weed problems, let alone having to purchase separate measuring cups/devices which adds up quickly in cost over time. 

In my opinion, if you’re only looking for a selective pre-emergent herbicide that quickly kills certain broadleaf weeds such as dandelions within 2 days after application without harming grasses then go with SummerGuard since it offers the following benefits:

1). Time savings 

It can be applied in mid-April through September (weather permitting) and lasts for 3-4 months in the soil.  Watering is only required within 2 days after application to ensure the highest weed control.  This saves you time having to apply pre-emergents multiple times during the season for persistent or winter weeds.

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2). Cost-effectiveness 

An 18 oz bottle is good enough for up to 9,000 sq ft of lawn area and can be applied twice per year in late summer/early fall and again in spring [approx $20-$25 depending on local prices].  

SummerGuard costs $50 per 16 oz concentrate which makes it cost-effective since there are no measuring devices needed when mixed with water (1 part concentrate: 4 parts water).  It also covers up to 5,000 sqft which might be enough for most people.

3). Selective weed control 

Kills certain broadleaf weeds such as dandelions and clover without harming grasses or desirable plants.

Read Also:- Does Lime Have Seeds? (Not seeds, but)

4). Safe for kids/pets once dry 

This is a major safety concern of pet owners since Scotts Step3 contains 17% 2,4-D which can cause severe irritation on skin contact that may result in rashes and even burns on your hands when you apply the product on your lawn.

It also kills plants so if you have flowers planted in your landscape beds, it will kill them after being applied on your lawn.

Scotts has been sued multiple times by consumers for its Step3 product’s safety issues. The company settled a class-action lawsuit in 2012 for $12 million after an Illinois woman developed rashes and burns on her arms after applying the product to her lawn.  

In 2013, the company also paid $6.2 million in a settlement with users who experienced severe skin irritation from using this product. 

In my opinion, if you have kids or pets running around your yard while you’re applying weed killers, you should choose something that is safe for them, especially when it comes to weed killers containing 2,4-D.

Price comparison: Scott’s Step 3 18 oz concentrate – $20 = 26 applications per 1 bottle + ingredients needed to be mixed with water.

Sunergard 16 oz concentrate – $50 = 53 applications per 1 bottle + no need to mix with water [2 parts water: 1 part summerguard]

  • Scotts Step3 – 17% 2,4-D
  • SummerGuard – 40% Prodiamine        

Based on a quick search online, it appears that the primary ingredient of Scotts Step 3 is 2,4-D. 

While this is effective at killing most common weeds, there are some reports of this having health effects on humans and pets if they come in contact with the product such as rashes and burns (see here). 

Read Also:- 7 Onion Growing Stages (+ How to Water It)

Final thoughts

I personally would not like to use products like this especially when Summer Guard can be purchased with only 40% prodiamine.

The good news is that if you have bought Scotts Step 3 in the past, you can take it back to your local Home Depot/Lowes for a full refund. 

If not, then I suggest purchasing SummerGuard which comes with 40% prodiamine and works without having to apply multiple times per season or worry about pets/kids coming in contact with this product when dry. 

Read Also:- Does Lime Have Seeds? (Not seeds, but)


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