Grass Out Max (Clethodim Herbicide)

4 out of 5 stars 103 Reviews | 167 Q&A

Grass Out Max (Clethodim Herbicide) - pint

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Average Rating

4 out of 5 stars Rating: 4.2

103 Reviews | 167 Q&A

Product Overview

Compare to Select 2EC and Arrow 2EC Herbicide. With Grass Out Max you get the same active ingredient for less expense.  It is highly recommended that you use a surfactant with this product. 

Grass Out Max is a selective post-emergent herbicide used to control annual and perennial grasses. It is labeled for most landscape, home and garden, ornamental, agricultural and non-crop uses. The unique feature of Grass Out Max is that it will ONLY kill grasses and NOT effect flowers, shrubs, broadleaf crops or other broadleaf plants. Grass Out Max contains 26.4% Celthodim Herbicide and effectively kills more than 50 different grasses.

Grass Out Max is only labeled for use on clover when used in the states of Idaho, Oregon, and Washington.

Features and Specs

Active Ingredient Clethodim 26.4%
Target pests Barnyard grass, Cheat grass, Canary grass, Crabgrass (hairy, large, smooth, southern), Foxtail, Goose grass, Rye grass, Annual Blue grass (Poa annua), and many others
Will Not kill Flowers, Shrubs, Broad-leaf Crops or other Broad-leaf Plants
See label for complete list
For use in Landscape, Home and Garden, Ornamental, Agricultural and non-crop areas
* See label for complete list
Application 16 oz. per acre
Add a crop oil containing 15% emulsifier at 1 qt. per acre
* Use a Surfactant to Increase Effectiveness
* See label for complete application instructions
Pet safe Yes, if used as directed on Label
Formulation Professional Product
NY, VT (Restricted To Licensed Applicators Only)
Shipping Weight 2.30 lbs
Manufacturer Agrisel
UPC 858916001204
EPA Registration 72159-15


Ground Application

Use a minimum of 5 gallons and maximum of 40 gallons of spray solution per acre. Use of sufficient spray volumes and pressure is essential to ensure complete coverage.

Under the following conditions a minimum of 10 gallons per acre is required: narrow row soybeans, broadleaf herbicide tank mixes, perennial grasses, volunteer corn, drought or stress conditions heavy grass pressure or when grasses are at or near maximum height. Failure to use a minimum of 10 gallons per acre under these conditions can result in poor coverage and reduced grass control requiring repeat applications. Spray pressures should reflect a minimum of 30 psi and a maximum of 60 psi at the nozzle. Do not use flood nozzles.

Applications to onions (dry bulbs and green), garlic, and shallots (dry blubs and green) should be made in a minimum of 20 gallons of spray solution per acre.

Review Search   
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  • 3 of 5 Stars

    Grass Out Max

    By Betty on 06/01/2017

    I barely applied the product and cannot say yet how effective it is. The product information booklet is extensive, but never states how many ounces to a gallon sprayer for use in home perennial beds. It says 8 oz. for an acre. I am guessing 1/2 oz./gallon for home use, but guessing is uncomfortable.

    Expert ResponseExpert response:
    Thank you for your review. I apologize that the label is extensive and confusing. We recommend using a surfactant like Non-Ionic Surfactant to help increase the efficacy of this product. If you use the surfactant, the recommended mixing rate for one gallon would be 2 tsp of surfactant with approximately .4 oz of the Grass out per gallon of water per 1,000 sq feet. Please let us know if you have any other questions.

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    211 of 228 people found this review helpful

  • 4 of 5 Stars

    Good grass killer

    By Joseph on 08/04/2014

    Verified Purchase

    I purchased this product to use on my food plots. It arrived timely, and I mixed the product with 2.5 oz per gallon of water. I mixed in some sticker as indicated, and used a backpack sprayer to apply. I didn't see any immediate action (first couple of days) but finally noticed that it was working. It took out the crab grass in my clover field without harm to the clover. My plots are about 1/3 acre; I would suggest that you map out a route to insure complete coverage if you use hand sprayer like I did, as I missed a few spots do to walking deviations. I recommend this product for use in food plots.

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    127 of 131 people found this review helpful

  • 5 of 5 Stars

    Takes Patience, But Very Effective

    By Happy on 09/29/2012

    Verified Purchase

    We have about 12000 square feet of lawn with curbing and beds throughout. Kentucky bluegrass creeping into the groundcover of the beds used to be a real problem. Then my neighbor introduced me to to Grass Out Max. He had used it the previous fall and his beds look great. He said it took about a month for it to work. I tried it and it and for the first couple of weeks didn't see much difference, but after a month it did the trick. Now just an occasional touch up application keeps the beds looking good.

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    65 of 67 people found this review helpful

  • 1 of 5 Stars

    grass out

    By Rusty on 01/12/2015

    Verified Purchase

    I don't think the product works. I have applied it twice and at this point no action. unless it kills the grass soon it was wasted money.

    Expert ResponseExpert response:
    What kind of plants are you trying to kill, and around which desirable plants? This product should be used with a surfactant, so you will only see limited results if you have applied it without adding a surfactant/spreader sticker to your diluted solution. You may also see limited or slower results during this time of year since the grass should be actively growing in order to absorb the herbicide. We would be happy to troubleshoot with you via email or via telephone at 866-581-7378 9a-5p EST.

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    51 of 55 people found this review helpful

  • 2 of 5 Stars

    Grass Out Max

    By Mike on 06/20/2012

    Verified Purchase

    I have used other products of this type meant specifically for grass eradication and this product was the least effective.

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    33 of 54 people found this review helpful

See all 103 customer reviews

Questions & Answers

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I purchased 'Grass Out' from you and it recommends adding a non-ionic surfactant,

I need to know how much to use of the Grass Out and the Surfactant. Do you mix it together and what is the percentage of each. Thank You.

If you are using Non Ionic Surfactant you would mix 2 tsp per surfactant with approx. .4 oz Grass out in one gallon water over 1000 sq feet. Please let us know if you have any more questions.

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103 of 116 people found this answer helpful

How long should I avoid watering or rain?
Grass Out Max (Clethodim Herbicide) should be rainfast within 4-6 hours after application. 

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85 of 90 people found this answer helpful

Can Grass Out Max (Clethodim Herbicide) be used as a spot treatment in flower beds?

I have completely read the product label and the answer to "per gal.concentrations" questions which will not do! I have a garden with irregular shaped flower beds where it is impossible to estimate 1000 square feet for the amount of 0.2-0.4 oz. Grass Out Max. Like most people in my situation I will be SPOT SPRAYING throughout these beds. How much per gallon is necessary for an effective concentration to kill on contact regardless of the area covered?!!!


There is an applicaiton ratio for spot treaments on the product label for Grass Out Max (Clethodim Herbicide) as well. You would mix .33 oz - .65 oz. per gallon of water. 

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83 of 94 people found this answer helpful

How long does it take before the grass dies with Grass Out Max?

You would see results with Grass Out Max within 10-14 days.

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76 of 81 people found this answer helpful

What is the mixing ratio of Grass Out to water for spraying flower beds?

I'm using Grass Out Max in a gallon sprayer for flower beds. In reading the labels, I can't find what amounts of grass max/water to use for that size container. Could you please give me that information?

You will need to use 0.2-0.4 fl oz of Grass Out per 1,000 sq ft area. Like most other herbicides the exact amount of water you use is not important, it is just important to make sure you get the specified amount of product over a 1,000 sq ft area. For ease of mixing/measuring you can add the specified amount of product to 1 gallon of water to apply to a 1,000 sq ft area.

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69 of 188 people found this answer helpful

See all 167 customer questions

Grass Out Max (Clethodim Herbicide) 4 out of 5 stars Rating: 4.2 (103 Reviews / 167 Q&A)

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