Tenacity Herbicide Calculator

Tenacity Herbicide Calculator


  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, total amount of water needed, and 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. 

Example, you ca 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 Type Species Rate per Acre
Kentucky Bluegrass (KBG) Poa pratensis 5-8 fl. oz. 
Centipedegrass Eremochloa ophiuroides 5-8 fl. oz. 
Buffalograss Buchloe dactyloides 5-8 fl. oz. 
Tall Fescue Festuca arundinacea 5-8 fl. oz. 
Perennial Ryegrass* Lolium perenne 5 fl. oz. 
Fine Fescue (creeping red, chewing and hard) Festuca spp. 5 fl. oz. 
St. Augustinegrass** (grown for sod) Stenotaphrum secundatum 4 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.

**This calculator calculates as low as 5 oz. per acre, and does not calculate for 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 day 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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