Monterey Nutgrass Killer II Selective Herbicide

1 out of 5 stars 1 Reviews | 5 Q&A

Monterey Nutgrass Killer II Selective Herbicide

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1 out of 5 stars Rating: 1

1 Review | 5 Q&A

Product Overview

The Monterey Nutgrass Killer II Selective Herbicide is a selective herbicide in a granular formulation which provides an excellent post emergence control of yellow and purple nutsedge, selected broadleaf weeds, kyllinga, horsetail and more. It contains Halosulfuron-methyl as its active ingredient and it is very effective in controlling unwanted weeds in your lawns, turf grasses, landscaped areas with established woody ornamentals, among others. Each box comes with .03-ounce granules in a water soluble bag.

Check zone map to see which plants will thrive at certain zones.

Features and Specs

Active Ingredient Halosulfuron-methyl 75%
Target pests Yellow and purple nutsedge, selected broadleaf weeds, kyllinga, horsetail and more
* See label for complete list
For use in Lawns, residential landscaped areas with established woody ornamentals, residential non-lawn areas, ornamental beds, and more
* See label for complete list
Application 1 packet per 1 - 2 gallons of water
Pet safe Yes, if used as directed on label
Coverage Area 1,000 sq. ft.
Time to Kill 2 Weeks
Shipping Weight 0.60 lbs
Manufacturer Monterey Lawn & Garden (Mfg. Number: LG 5402)
UPC 22179103290
EPA Registration 228-711-54705



Mixing Instructions

This product is a water dispersible granule designed to be diluted with water at the rates listed in the use direction. Fill the tank with approximately 1/2 of the desired volume with water. With the agitation operating, add the specified amount of the formulation as listed in the use directions. Complete the filling process while maintaining agitation. Add nonionic surfactant as the last ingredient in the tank. Allow time to fully disperse.

Since this product forms a suspension in water, it is important to maintain good agitation during mixing and spraying. If the spray suspension is allowed to settle for a short period of time, be sure to agitate the spray suspension for a minimum of 10 minutes. Apply spray solutions within 24 hours after mixing.

Application Methods

Apply this product to produce uniform coverage on growing weeds or soil to achieve consistent weed control. Loss in effectiveness or lawn injury may result if weeds are under drought, stress, disease or insect damage.

Uniform, thorough spray coverage is important to achieve consistent weed control. Calibrate application equipment prior to application of this product. Application should be uniform and of sufficient volume to avoid streaking or skips. Avoid excessive overlap of the spray. It is important to thoroughly clean all application equipment immediately after use with a triple rinse procedure. It is recommended that the second rinse be made with a water solution that contains 1% vol/vol ammonium.

Spray Drift Management

  • Do not apply more than 0.12 ounces of this product (0.0057 lb. active ingredient) per 1,000 sq. ft. per use season.
  • Increase in lawn injury may result if the seeding depth is too shallow and excessive amounts of water (greater than 1 inch) from rainfall or sprinkler irrigation occurs.
  • Avoid spraying when conditions favor rainfall or using overhead sprinkler irrigation within 4 hours of this application.
  • The maturity of the lawn may be delayed by use of this product.
  • Use nozzles and pressures that minimize the production of fine particles that drift outside of the targeted area.
  • Do not apply this product to drift outside of targeted area.
  • Applications of this product may cause temporary yellowing or stunting of the lawn.
  • When this product is applied over the top of a blooming lawn, bloom loss may occur under certain environmental conditions.
  • Do not apply this product if the target weed or lawn is under severe stress due to drought, water-saturated soils, poor fertility (especially low nitrogen levels), hail, frost, insects or when the maximum daytime temperature is above 92 degrees Fahrenheit. Under these conditions, applications may cause temporary lawn injury.
  • Do not mow lawn for 2 days before or 2 days after application for best results.
  • When transplanted into landscaped areas treated with this product, flowers, ornamentals, plants and shrubs may be injured.
  • Avoid contact of the spray containing this product to desirable flowers, ornamentals, shrubs or trees as discoloration, severe foliar injury or death may result.
  • Do not store unused diluted product in sprayer. Use up all product at time of application as directed on the label.
  • Do not exceed the specified amount of spray additive due to the potential for lawn injury at higher rates.
  • For this product in water soluble bags - Do not pierce or open water soluble bag.

Application Directions

For post-emergence control of purple or yellow nutsedge, Kyllinga and broadleaf weeds spray the target weeds thoroughly and wet the entire leaf surface of the undesirable plants. For best results, spray nutsedge after it has reached the 3 to 8 leaf stage of growth.

This product often works with one application, but depending on the size and age of the nutsedge a second treatment may be required 6 to 10 weeks after the initial treatment.

Sequential Treatments - To maximize the control of nutsedge, a second post-emergent spot or broadcast spray is applied 6 to 10 weeks after the initial treatment to the areas where nutsedge has regrown or emerged.

Woody Ornamentals in Landscaped Areas

Use this product as a post-directed spray at the specified use rates around established woody ornamental plants in residential landscaped areas. Do not contact trees, roses, flowers, and shrubs as injury will occur. If applications are to be made to transplanted woody ornamentals, allow 3 months after transplanting before applying this product.

Application Prior Planting of Lawns or Woody Ornamental Plants

This product may be used prior to the establishment of lawns or woody ornamental plants. Wait 4 weeks between application and seeding or sodding of lawns, or transplanting woody ornamentals.

For Horsetail Control in the Following Residential Non-Lawn Areas: Landscaped Areas; Ornamental Beds; Edges of Lawns; Along Driveways, Fences, Sidewalks, Walkways, Patios, Retaining Walls, and Foundations:

Apply this product at specified rate as a post-emergence spray on specified use sites. When applied post-emergence, this product will suppress the following weeds: cocklebur, common sunflower, common ragweed, giant ragweed, pigweed, and velvetleaf. This product may be tank mixed with Glyphosate herbicide.

Control of Horsetail (Equisetum arvense)

For post-emergence control of horsetail (Equisetum arvense) apply after horsetail has leafed out. This product will control horsetail that is less than 6 inches tall and suppress horsetail that is greater than 6 inches tall.

Herbicide symptoms are likely to show within 2 weeks as a necrotic ring at the base of the plant, even though the leaves and stems remain green and a deep leathery green in color.

(See label for complete list and instructions.)


What is Nutgrass Killer II?
It is a post emergence selective herbicide based on the active ingredient halosulfuron-methyl for use on turf and ornamental areas to control yellow and purple nutgrass (nutsedge), kyllinga and horsetail. Many university research studies show halosulfuron-methyl to be the most effective nutgrass control product available to the homeowner for use on turf.

What turf species can I use Nutgrass Killer II on?
All turf species.

How do I use Nutgrass Killer II?
It comes in a premeasured water-soluble pouch that is added to 1-2 gallons of water to treat approximately 1000 sq ft. Add 2-4 teaspoons of a non-ionic surfactant such as our Herbicide Helper for best results.

When do I apply Nutgrass Killer II?
Wait until the nutgrass has reached the 3-8 leaf stage. A second treatment 6-10 weeks later may be needed if regrowth occurs.

What precaution should I observe?
Do not mow for 2 days before or 2 days after an application. Do not irrigate, and avoid rain for 4 hours after application. Only use on well-established turf. You can overseed with ryegrass 2 weeks after application. Avoid drift onto desirable plants. Keep people and pets off of the treated area until the spray has dried.

Can I use Nutgrass Killer II on ornamentals?
Yes it can be used around woody ornamental plants. Do not contact the leaves and do not use as an over-the-top spray.

How is Nutgrass Killer II packaged?
It comes in an individual kit which contains a label and a pouch of material (.03 oz). The foil pouch is to be opened and the water-soluble bag dropped into the spray tank without opening the bag, which is designed to dissolve in water.

How do I control horsetail in residential sites?
Use the same rate as turf but apply to 500 sq ft. rather than 1000 sq ft. If horsetail are less than 6” they will be controlled, if larger they will be suppressed. Control may take 2-4 weeks.

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  • 1 of 5 Stars

    Use Prosedge or Hi-yield

    By Benjamin on 11/30/2017

    Verified Purchase

    I have always used either Prosedge or Hi-yied to kill Nutgrass. I actually accidentally ordered this one, and was not pleased. It seemed to have no affect on the Nutgrass in my Bermuda/Rye lawn. This was twice the price, and no result.

    Expert ResponseExpert response:
    Thank you for your feedback! We are sorry that you did not see the desired results from the Monterey Nutgrass Killer. This product does require the use of a surfactant for best results. You will also need to give the product about 14 days to start seeing results on the target weeds, and more mature nutsedge can require two applications 8 to 10 weeks apart. It is also possible that the weeds you are treating may not be yellow nutsedge, but a more difficult weed such as kyllinga which can be difficult to identify. Please feel free to reply to our email or give us a call at 866-581-7378 M-F 9a-5p EST to troubleshoot or if you have any other questions or concerns.

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    2 of 2 people found this review helpful

Questions & Answers

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Can I use Monterey Nutgrass Killer II Selective Herbicide in my garden?

I have tomatoes, peppers and brussel sprouts planted.


Monterey Nutgrass Killer II Selective Herbicide is not labeled to be used in edible gardens, only in lawns and ornamental landscapes.  For nutsedge in garden areas it is recommended to spot treat the sedge with a glyphosate or Round Up type product directly.  We recommend Roundup QuickPro 1.5 oz. packs for ease of use.

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Can Monterey Nutgrass Killer II Selective Herbicide be used in a vegetable garden area?

I have nut grass in my raised garden beds and need something to kill it.


Monterey Nutgrass Killer II Selective Herbicide cannot be used in veggie gardens. For nutsedge in landscaped areas it is recommended to spot treat the sedge with a glyphosate or Round Up type product directly.  We recommend Roundup QuickPro 1.5 oz. packs for ease of use

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Can Monterey Nutgrass Killer II Selective Herbicide be used with annual ryegrass, which is overseeded for winter lawns?

Monterey Nutgrass Killer II Selective Herbicide should be used over established lawns. It is recommended that you mow the lawn at least 3 times before applying this product to an overseeded area. The product is safe for use on established annual ryegrass.

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How much does Monterey Nutgrass Killer II Selective Herbicide yield?

Monterey Nutgrass Killer II Selective Herbicide is mixed at 1 packet per 1-2 gallons of water yielding 1-2 gallons of mixed solution in a hand held sprayer for application.

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Does Monterey Nutgrass Killer II Selective Herbicide kill the sedge nutlets that are underground or just the grass?

Nutlets are hard to control and may require multiple applications of Monterey Nutgrass Killer II Selective Herbicide.

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