tenacity herbicide

Tenacity Herbicide Calculator

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Written By: Mark Marino

a Massachusetts Core Applicator License holder and owner/operator of Lawn Phix,

Updated on


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  1. Select if used as a Pre-Emergent (weed prevention) or as a Post Emergent (weed killer)
  2. Select Low or High rates of Tenacity Herbicide (see below for more details)
  3. Type your total square feet you’re looking to cover

Trying to calculate how much Tenacity herbicide to apply to your lawn? Use our new Tenacity Calculator to accurately calculate the amount of Tenacity to apply. Choose as a Pre-Emergent or Post Emergent and this calculator will tell you how much Tenacity to apply, the amount of Non-Ionic Surfactant (NIS) if post-emergent, the total amount of water needed, and the maximum amount of Tenacity you can apply per year based on your total square feet.

Below is from the label of Tenacity. This can be helpful when using the calculator above. 

Tenacity Application Rates

Tenacity Mix RateFor pre-emergent and post-emergent applications, apply 4 to 8 ounces of Tenacity per acre in at least 30 gallons of water per acre. For spot treatments, mix 0.33 ounces (0.5 teaspoons) of Tenacity Herbicide in 1 gallon of water to treat 1,000 square feet.
Tenacity Pre-Emergent Mix RateMix 1/2 teaspoon of Tenacity to 1 gallon of water to cover 1,000 sq ft. Water in with 1/4″ of irrigation or rainfall within 1-2 days of application
Tenacity Post-Emergent Mix RateMix 1/2 teaspoon of Tenacity with 1 1/2 teaspoons of non-ionic surfactant (NIS) to 1 gallon of water to cover 1,000 sq ft.

For example, you can safely use the “High rates” of herbicide on Kentucky Bluegrass (KBG) and Tall Fescue (8 oz. per acre). However, you will want to calculate the “Low Rates” for grasses such as Perennial Ryegrass (PRG) and Fine Fescue (5 oz. per acre)

Grass TypeSpeciesRate per Acre
Kentucky Bluegrass (KBG)Poa pratensis5-8 fl. oz. 
CentipedegrassEremochloa ophiuroides5-8 fl. oz. 
BuffalograssBuchloe dactyloides5-8 fl. oz. 
Tall FescueFestuca arundinacea5-8 fl. oz. 
Perennial Ryegrass*Lolium perenne5 fl. oz. 
Fine Fescue (creeping red, chewing, and hard)Festuca spp.5 fl. oz. 
St. Augustinegrass** (grown for sod)Stenotaphrum secundatum4 fl. oz. 

Check out my Tenacity Herbicide Review. How I went from zero to hero in a matter of a few weeks after using Tenacity, killing all my creeping bentgrass, and dominating the neighborhood with my new GCI TTTF lawn. 

Before applying any lawn chemicals, always read the labels. Read the Tenacity Herbicide Label here. For more details on how long before Tenacity is rainfast.

More questions? Check out our huge Tenacity herbicide FAQ guide.

**This calculator calculates as low as 5 oz. per acre, and does not calculate the recommended amount for St. Augustine.  

What is the maximum amount of Tenacity I can apply per year?

The maximum amount of Tenacity herbicide you can apply each year is 16 fl. oz.per acre. This equates to approximately 0.367 ounces per 1,000 sq. ft.

How much Tenacity is used per 1,000 sq. ft.?

Depending on your grass type, you can apply between 5-8 fl. oz. of Tenacity per acre. This equates to approximately 0.11 – 0.18 fl. oz. per 1,000 sq. ft. The exception is St. Augustinegrass which is 4 fl. oz. per acre.

How much water is needed for applying Tenacity herbicide?

According to the Tenacity herbicide label, you will need 1 gallon of water for every 1,000 sq. ft.

Can Tenacity be applied as both a pre-emergent and post-emergent herbicide?

Yes. If Tenacity is used as a pre-emergent, you will not use a Non-Ionic Surfactant (NIS) and water the product in with 0.25″ of water.

When used as a post-emergent, you will use 3x the amount of NIS than Tenacity. Water should not be applied to Tenacity for at least 4 hours after when used as a post-emergent.

Can I mow my lawn before applying Tenacity?

Whether you use Tenacity as a pre-emergent or post-emergent herbicide, you should wait two days before and two days after applying Tenacity.

Example: Mow on Monday, apply Tenacity ~48 hours later on Wednesday, and mow ~48 hours after on Friday.

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Author's Note: this piece has been updated for accuracy since its first publication on
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Author: Mark Marino
My name is Mark Marino, and I am the founder, owner, and operator of Lawn Phix. With a passion for lawn care and turf nutrition for over a decade, I've dedicated countless hours to correcting soil and perfecting lawns. Today, my expertise, backed by formal courses at UMass Extension Pesticide Education, allows me to offer top-tier lawn care services and advice. I am a fully licensed and insured lawn care applicator in Massachusetts, specializing in comprehensive turf nutrition, weed control, and lawn pest control. My license number is AL-0053865. Contact me at [email protected] or +1 (508) 500-8402.

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