Sumo Gardener

Spectracide vs Roundup: Which Brand Works Better?

Are weeds making your lawn look hideous? Are you confused with multiple herbicides available in market? I also faced a dilemma when choosing the right weed killer. 

So, I struck a comparison between the 2 non-selective post-emergent herbicides I had zeroed upon- Spectracide vs Roundup. Both differ in their core ingredients which works to kill weeds. 

Spectracide contains diquat, while Roundup contains glyphosate. Both diquat and glyphosate work upon visible weeds seen on top of the soil. Read on to learn more. 


What is the difference between Spectracide vs Roundup

Spectracide vs Roundup: Which to Use?

Spectracide Weed Killer's Key Ingredient

Spectracide Grass and weed killer’s key active ingredient is diquat. The method of application for this herbicide is basically spraying. As soon as spectracide is sprayed on the weed, it starts destroying the weed. 

Diquat dibromide wipes out that plant portion being actually touched. Therefore, careful spraying on weeds growing between plants or in the lawn can help eliminate them without affecting other plants or the lawn.

Spectracide Effects

Spectracide Weed & Grass Killer

via Amazon

  • Can kill 200+ weeds
  • Shows results within 3 hours/3 weeks depending on weed toughness
  • Doesn’t leave any residues on soil
  • Best suited in flower beds, patios, driveways, walkways, around shrubs & trees.

If you accidentally spray spectracide on any beneficial plant, quickly rinse it off with water.

Roundup Weed Killer's Key Ingredient

Roundup weed killer's key ingredient in Glyphosate. It blocks some segments of the PEP molecule which is responsible for plants and animals metabolism.

Roundup weed and grass killer is also applied through spraying. It enters the plants through the leaves, reaches the roots and kills it off. If you are looking for a full-proof solution to eliminate old weeds once and for all, roundup can be a great pick.

Read also: Ortho Ground Clear Vs Roundup

Roundup Effects

Roundup Grass killer

via Amazon

  • Spray the solution in a sunny day for best outcome
  • Spray it wherever active weed growth is visible
  • Weeds droop in 2-4 days and die by 1-2 weeks
  • Great to use in flower beds, around driveways, trees and fences. Can also be used between crops and no croplands
  • Can kill big leafy weeds such as weedy grasses, sedges, woody plants & dandelions

Avoid application of roundup weed killer during a windy day. Winds will let the spray drift off to other plants and kill them. To specifically kill weeds growing between flower beds or crops, spray during a calm hour of the day.

Read also: Will Roundup Kill Trees?

After thoroughly going through the two definitions, I have made a comparison between these two herbicides.

Spectracide and Roundup's Similarities

Spectracide weed and grass killer as well as Roundup are post-emergent by nature. This suggests that:

  • New weeds can be easily eliminated by Spectracide as well as Roundup
  • Weeds that have started generating seeds or have been frazzled by drought can be tough to clear out by the two herbicides
  • Older weeds can be destroyed completely by Roundup

Spectracide and Roundup are also non-selective. In other words, they can eradicate weeds, grass as well and all other types of plants. Therefore both their usage should be strictly focused on:

  • Weeds;
  • Particular spots where weeds grow;
  • Before planting the turf.

However, they are differentiated by the killing method.

Spectracide vs Roundup's Killing Method

Spectracide only eradicate the portion of the weed right after it comes in contact with, whereas any tubers/ rhizomes present underground will continue to exist.

Weeds can grow back from these tubers/ rhizomes. Multiple spraying of spectracide will be needed to completely destroy such weed growth.

Roundup, on the other hand, kills the weeds in a systematic manner. It slowly enters the plants along with water and nutrients. Great choice for big weed plants! Of course, you might need to be patient as it will take some time to kill the large weeds.

For more details on weed killers, see our buyers' guide on the best weed killer for lawns in 2024

Spectracide vs Roundup Verdict

Finally, I would say that spectracide is a good pick for fresh or smaller weeds while roundup is perfect for bigger and older weeds. Both the herbicides are extremely toxic (inhaling/ingestion), and should be handled very carefully.

Glyphosate is dangerous for environment. Whichever herbicide contain it has been prohibited by The European Union. There you have it! Those are our ur take on Spectracide vs Roundup weed killers! 

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About the Author Pat Moreno

Pat is our gardening tool expert here at Sumo Gardener. Working for many years as a private and commercial landscaper, Pat has used almost every type of gardening tool there is. Along with a vast knowledge for types of plants and putting together an amazing looking and maintainable garden, Pat developed a passion for gardening tools as he found that using the right tools vastly improved the ease and outcome of any landscaping job he undertook. When spending hours, days or years using a particular tool, you want to make sure you’ve got the best one for the job, and Pat is the right guy to guide us to the best gardening tools.

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