2-4-D Amine Mix Ratio Per Gallon | What Weeds Does It Kill

The active ingredient 2-4-D (short for 2,4-dichlorophenoxyacetic acid) is a special formula used for vegetation control. It controls weeds without significantly affecting turf grasses, making it one of the most popular weed killers for lawns. 

Effective weed management requires the use of a proper 2-4-D amine mix ratio. A slight variation in this ratio may result in poor weed control, which can result in wasted money, effort, and time.

How Much 2-4-D Per Gallon of Water To Use

2,4-D is an herbicide that kills broadleaf weeds by changing the growth pattern of specific cells. It causes the cells carrying water and nutrients to the weeds to divide and grow non-stop. It comes in several chemical forms, such as acids, salts, and ester. The first step in successful weed management is understanding how and when to use the herbicide safely and effectively.

Observing a proper 2,4-D mixing ratio is essential. Otherwise, you may need to make repeated applications to manage your weed problem.

2,4-D Mixing Ratio

Generally, you should use 5 tablespoons (2.5 oz) of 2,4-D per gallon of water per 400 square feet of weed-laden grass. But, to be more specific, how much 2,4-D amine per gallon of water is needed depends on the application method you choose.

Mixing 2,4-D For A Hand Sprayer Or Backpack

When using a tank or backpack sprayer, you can use the generic 2,4-D mixing ratio of 5 tablespoons (2.5 oz) of liquid concentrate per gallon of water to treat 400 square feet of yard. You can double the amount of liquid concentrate for two gallons of water to treat 800 to 1,000 square feet of yard area. 

Apply the herbicide evenly over the grass to give enough coverage. You don’t need to wet the grass thoroughly to the point of pooling on the soil. 

Mix Ratio For 2,4-D Hose-End Sprayers

You can attach multi-use spray applicators to the end of your garden hose. For the proper mixing ratio, set the dial to release 2.5 oz of liquid concentrate per gallon of water. 

A 16oz reservoir used with the proper settings is enough to treat up to 2,500 square feet of yard area. Don’t add water to the reservoir because the sprayer automatically dilutes the liquid concentration as water flows through the garden hose. Just multiply the length by the width of your yard to get its total area.

2,4-D Mixing Ratio For Spray Bottles

If you opt to spot treat weeds in your garden or lawn, you may use a spray bottle. Make sure to select a pesticide spray bottle for this purpose. Simply dilute 2.5 tablespoons (1.25 oz) of 2,4-D in a 32oz spray bottle. This 2,4-D mixing ratio is enough to treat a 250-square-foot yard area. It’s effective in killing many weeds quickly. 

To ensure better coverage of targeted weeds, you can add a suitable and approved surfactant to your mixture. Just ensure not to use the same spray bottle for fungicides and insecticides to avoid cross-contamination.

How Many Acres Will A Gallon Of Diluted 2,4-D Treat?

When using 2,4-D herbicides, dilute a gallon in 15 gallons of water to cover an acre of land. The maximum application rate is 1.8 gallons per acre per season, which must be limited to two applications annually.

Typically, the spray volume is 5 to 20 gallons of water per acre by ground equipment and 1 to 5 gallons by aircraft. You can use larger amounts as required to ensure uniform coverage of weeds and brush. 

Additionally, lower dosages are explicitly recommended for young and sensitive weed species. Higher rates are needed for less sensitive and fast-growing weed species where control is difficult.

When diluting 2,4-D with water, don’t mix with oil, surfactants, atrazine, or other adjuvants unless specified on the label. Some deeply rooted perennial weeds need repeated applications for effective control. 

It’s important to note as well not to use the same applicator or equipment for applying other products to 2,4-D susceptible crops to avoid damage.

Is 2,4-D Harmful If Mixed Incorrectly?

The rate and timing of application are very crucial in weed management. Spraying incorrectly often results in crop injury and poor weed control. 

For instance, having a highly concentrated mixture can damage the crop and grass, which were previously resistant to injury from herbicides. Remember, too many chemicals can do severe damage to crops and ornamental plants.

While 2,4-D shows excellent results as a practical herbicide, it has often been misused, resulting in crop injury. If used with proper care and discretion, it is an effective tool in weed management. Knowing how much 2,4-D amine per gallon to use is necessary to maximize its efficacy. 

Can You Use Too Much 2,4-D?

If a ratio of 2.5oz of 2,4-D per gallon of water is used across 400 sq ft, there is no risk. Using incorrect mix ratios can lead to scorching or burning of the surrounding vegetation. Also, excessive use of diluted 2,4-D can lead to surface runoff into nearby waterways, creating a potential risk to vulnerable wildlife.

How To Apply 2,4-D Spray

Before applying the 2,4-D spray, learning about the various forms of 2,4-D is essential. The most common forms are acids, salts, and esters.

  • Acids. The 2,4-D acid is a dry material that is insoluble in water. Generally, it needs mixing with a liquid carrier that keeps it in solution when diluted in water. The liquid preparation varies with the amount of 2,4-D, the carrier used, and the derivatives.
  • Salts. The salts, such as ammonium salt or sodium, are dry powders easily prepared and readily dissolved in water. The preparation includes a wetting agent to make it possible to cover the area evenly.
  • Esters. The esters of the acid dissolve in water at a slower rate than the salts. That’s why esters are typically sold in oil preparation that readily mixes with water and forms an emulsion.

Here’s a step-by-step procedure on the application of 2,4-D:

  • Prepare the things you need.
  1. Personal protective gear
  2. Surfactant
  3. High-pressure tank sprayer
  • It’s essential to wear protective gear before you start mixing or spraying 2,4-D herbicides. According to the World Health Organization, 2,4-D is a potential human carcinogen and exposure to 2,4-D is linked to Hodgkin’s lymphoma and sarcoma. 

Thus, it would be best if you put on a long-sleeved shirt, long pants, safety glasses, socks, and chemical-resistant footwear to protect yourself from direct contact with 2,4-D.

  • Only apply the herbicide when the wind speed is below 6 to 7 mph. After all, it is better safe than sorry, and you do not want the product blowing into places you don’t want it.
  • Get the spray tank and attach a flat fan nozzle tip. Set the pressure to 20 psi. Then, start the agitator and keep it running while the mixing and application process is ongoing.
  • Slowly fill the tank with 1/2 gallon of water and add 2.5 tablespoons of 2,4-D herbicide. Then fill it with another 1/2 gallon of water.
  • You may add one tablespoon of surfactant to the mixture. You can use liquid dish soap instead of a commercially available surfactant. This helps the herbicide stick to the targeted weeds.
  • Fill the tank with 1/2 gallon of clean tap water. Add 2 to 3 tablespoons of 2,4-D herbicide. Fill the tank with another 1/2 gallon of water.
  • After completing the mixture, apply the herbicide as a spot treatment on individual weeds. Be sure to spray the top and bottom of the leaves and stems. Avoid inhaling the fumes from the spray or letting the herbicide come into contact with your bare skin.
  • After application, leave the treated area until the herbicide has completely dried. Be sure to keep children and animals away from the site.
  • If there is any remaining solution, make sure to dispose of it properly at a local hazardous waste center. Clean the tank thoroughly after using it. Make sure to wash all the protective gear used separately.

Now you know how to effectively apply the 2,4-D spray and how much 2,4-D amine per gallon you should use. Here are some additional tips when using this herbicide:

  • The 2,4-D herbicide takes effect slowly. You may notice it takes up to a month before the weeds actually die.
  • It usually takes two or more applications to kill many types of perennial weeds for good.
  • The use of 2,4-D herbicides may result in soil sterilization. How long this lasts depends on the number of chemicals used, rainfall or irrigation, temperature, the soil composition, and the planted crop.
  • Thorough cleaning of bottle sprayers and other equipment is crucial before being used again for different materials.
  • The herbicide spray or dust should never reach susceptible crops and ornamental plants. Even small amounts of herbicide are very injurious.
  • The acid form of 2,4-D is non-toxic to both humans and animals. It’s also non-corrosive and neither inflammable nor explosive.

Does 2-4-D Require A Surfactant?

A surfactant is a wetting agent used for herbicides to increase their coverage, penetration, and overall effectiveness. It can be used with almost all types of herbicides, including the 2,4-D amine.

Surfactants help by reducing the surface tension of water to create a uniform coverage of weed killers. The addition of a surfactant can help improve the control of broadleaf weeds, including wild oats, common vetch, and sweet yellow clover.

For the 2,4-D herbicide, it’s recommended to use a non-ionic surfactant. Mix 1 teaspoon of surfactant per gallon of spray or 1 to 2 pints per 100 gallons of spray.

When Is The Best Time To Apply 2-4-D Amine?

Before any herbicide application, you need to consider factors such as moisture level, temperature level, and wind speed to ensure effective management and elimination of weeds:

  • Moisture level. The moisture level of the area is critical when applying 2,4-D herbicides. If there are high levels of moisture, the 2,4-D application will most likely fail.
  • Temperature level. Similar to other agricultural factors, temperature plays a vital role when applying herbicides. 2,4-D is highly effective with warmer temperatures and relative humidity. 

However, be careful with temperature inversion because it may result in off-target drift. When warm air is suddenly replaced with cold air, it may result in 2,4-D going airborne until the end of the inversion.

Additionally, the herbicides may have been applied off-target, negatively impacting nearby areas and missing out entirely on the intended purpose.

  • Wind speed. Another vital consideration is wind speed. Although it’s challenging for you to wait for the optimal wind speed, it’s still worth every second of waiting when you know the adverse effects of applying herbicides with inappropriate wind speed.

The University of Minnesota recommends a wind speed of 3 to 7 meters per second. Any rate beyond this limit may interfere with the herbicide application, leading to herbicide drift off target. 

Additionally, wind speeds below 3 meters per second can lead to ineffective application, especially when there is a temperature inversion. It’s also important to consider the wind direction.

The application of 2,4-D should be made when there is active growth. Avoid applying herbicides during the spring season because it’s less effective than fall applications. Weeds actively transport food and nutrients from their foliage to the roots during the fall season in preparation for the winter season. 

You can take advantage of this by applying herbicides during the fall so they are optimally absorbed by the foliage. The pesticides then get transported to the roots together with the food. This leads to the rapid destruction of weeds.

How Long Does 2 4-D Take To Work?

It usually takes 7 to 14 days for 2,4-D amine to completely kill weed roots and vegetation. Clear signs of dying weeds are visible within 48 hours of 2,4-D application. Indications include wilting and discoloration of the leaves as they turn from green to brown.

The moisture content of the area also affects the efficacy of the herbicide. If the conditions are too wet, the esters and salts of the 2,4-D may break down too quickly. This reduces the effectiveness of 2,4-D and increases the expected time of action. 

To prevent this from happening and to ensure that it won’t take too long to kill the weeds, adhere to the following steps:

  • Apply herbicides when the weeds are young and actively growing.
  • Make sure to apply during appropriate wind speed to prevent drift and crop injury.
  • Apply herbicides when the temperature is below 90 degrees Fahrenheit.
  • Apply herbicides during dry weather to increase the absorption rate of the weeds.

How Long Does 2-4-D Need To Be On Before Rain?

When it comes to the application of 2,4-D, the rule of thumb is that it should be done at least 24 hours before the rain to ensure maximum absorption by the weeds. The 2,4-D ester formulation has a rainfast period of an hour, while the amine formulation becomes rainproof within 6 to 8 hours.

Just remember that the rainfast period varies per product available on the market. Thus, it’s necessary to read the product label to know how long the herbicide has to be on before rain or before you water the lawn.

Watering the lawn before the specified rainfast period elapses will result in you needing to respray the herbicide within 48 hours to ensure the efficacy of eliminating the weeds. The same process is done if there is unexpected rain before the herbicide becomes waterproof.

What Weeds Does 2-4-D Amine Kill?

The 2,4-D herbicide works effectively on most weeds. However, it acts more slowly than other products on the market since it needs at least a month to kill weeds completely.

The herbicide works quicker in warmer temperatures. But cooler temperatures ultimately produce the same results. Results observed in some weeds include:

  • Russian knapweed. When Russian knapweed is treated in its early rosette stage, 2,4-D can kill 95 to 100% of it. It’s quite challenging to wet the Russian knapweed – that’s why it requires a wetting agent to be added to the spray.
  • Klamath weed. Unlike the Russian knapweed, early sprayings on the Klamath weed are not effective. It’s recommended to wait for it to be developed and established before treatment. Ensure that treatment is done before its bloom stage.
  • Cattails. Even when cattails are deeply rooted below the water surface, proper application of 2,4-D is still effective in eliminating these weeds. They develop resistance during early summer. 

Thus, adding three gallons of diesel oil to a 100-gallon spray is recommended to improve the herbicide’s penetration into the weeds’ waxy surface. Ester formulations are also effective on these species.

  • Dandelion. Dandelions are highly susceptible to 2,4-D. Usually, one application kills the entire weed infestation.
  • Wild blackberry and poison oak. These species are not significantly affected by a single application of 2,4-D in early spring. However, later applications after complete leafing have more promising results. These species are also water-resistant.
  • Water weeds. Floating water weeds, such as yellow waterweed, hydrocotyle, and water hyacinth, are easily killed by a single application of 2,4-D on their above-water portions.
  • Nutgrass. Although nutgrass is a sedge rather than actual grass, it’s not very susceptible to herbicide. Repeated applications are needed to kill the underground nuts.

In addition, 2,4-D is also effective in killing various other weeds that include:

  • Alder
  • Canada thistle
  • Coffeeweed
  • Goldenrod
  • Jewelweed
  • Nettle
  • Pennycress
  • Pepperweed
  • Purslane
  • Ragweed
  • Red clover
  • Sagebrush
  • Sweet clover
  • Toadflax
  • Tumbleweed
  • Velvetleaf
  • Virginia Creeper
  • Wild carrot
  • Wild parsnip

It’s essential to keep in mind that several factors affect the success of the treatment, such as weed susceptibility, stage of growth, ease of wetting, amount of leaf surface, weather conditions, and the quality of the weed killer.

What Type of Grass Can You Use 2-4-D On?

Of all the crop plants, only cereals and most grasses are resistant to 2,4-D. These grasses include annual bluegrass, Bermuda grass, blackberry, foxtail, crabgrass, Italian ryegrass, horsetail, poison oak, quack grass, watergrass, wild barleys, and many more. 

Since the grass family is more resistant to 2,4-D than broadleaf weeds, the chemical is commonly used as a spot treatment in grain fields, including:

  • Barley and wheat. The application rate is 8 to 12 oz of 2,4-D per acre, which is mixed with 100 to 200 gallons of water. While there are reports of crop damage when very young wheat grass is treated, no injuries are reported on grains 4 to 6 inches high. 

On the other hand, mustards, wild radish, star thistle, and fiddle-neck are killed readily when treated during their early stages.

  • Rice. To successfully kill weeds, such as water plantain, arrowhead lily, burhead, and other water weeds in rice fields, airplane application of 2,4-D is usually carried out. 

The typical treatment is 15 gallons of spray per acre, containing 16 to 24 oz of 2,4-D. When applying to an area where there’s low water, some crop injuries are observed. But no crop injuries are reported when sprayed on fields where the water’s up and plants are well-established.

  • Corn and milo. A single treatment application before the crops cover the rows reduces the infestation of perennial weeds, such as kelp and wild morning glory. The recommended amount is 16 to 24 oz of 2,4-D per acre.
  • Turfs and grass pastures. Treat these areas with 16 to 24 oz of 2,4-D mixed with 100 to 200 gallons of water – enough for an acre. If the grasses are still at the earlier growth stage, don’t use more than 12 oz of 2,4-D. 

Remember not to treat grass seed fields when plants are in bloom. In grass pastures, using 2,4-D can significantly kill broadleaf plants, such as filarees and clovers.

  • Lawns. For treating lawns, mix 24 oz of 2,4-D with 200 gallons of water per acre. Treatment application is very effective in killing plantain, dandelion, bu clover, chickweed, pennywort, green oxalis, speedwell, heal-all, and mouse-ear chickweed. As mentioned previously, the treatment doesn’t affect crabgrass, Bermuda grass, and red oxalis.

Plants To Avoid Using 2-4-D On

Many crop plants are seriously damaged by contact with 2,4-D chemicals. That’s why using the 2,4-D herbicide has been limited to managing weeds in lawns, grain fields, and grass pastures. 

Ensure that when spraying an area, don’t allow the spray to reach nearby crops or ornamental plants because, even in small amounts of drift, susceptible plants are likely to experience injury. 

The Takeaway

Understanding exactly how much 2,4-D amine to use per gallon of water can be a huge asset in your fight against weeds. Be sure to keep in mind the important tips mentioned here for effective applications. In the end, your yard will thank you for it. And you will have a beautiful lawn that has never looked better!