How Much 2,4-D Per Gallon of Water? (Mixing Directions)

2,4-D is a popular post-emergent herbicide used to control broadleaf weeds.  It is produced in several chemical forms including liquid form (concentrated or ready-to-use), dust, or granules. To get the best result, you need to mix the herbicide in the right ratio. So how much 2, 4-D per gallon of water?

Mix 2.5 oz of 2, 4-D weed killer per 1 gallon of water to treat about 400 square feet of the area covered in weeds. Most importantly, use the mixing ratio recommended by the manufacturer on the label as every product has its mixing ratio and instructions.

How Much 2,4-D Per Gallon of Water?

2,4-D is an auxin-type herbicide that kills broadleaf weeds by making the cells in the tissue that carry water and nutrients divide and grow without stopping. This disables a plant to carry out important physiological processes.

There are many 2,4-D herbicides in the market produced by different companies. They are safe to use on a lawn for killing weeds such as dandelion, chickweed, clover, ground ivy, poison ivy, thistle, bitterness, and bindweed. However, you need to use the correct ratio when mixing.

Like other broad-leaf weed killers, using too much 2,4-D weed killer will not only kill the weeds but also your lawn grass. On the other hand, using too little will be ineffective as it will not kill the weeds as intended.

Most 2,4-D weed killers have a mixing ratio of 1 to 5 ounces per gallon of water. However, the exact ratio is given by the manufacturer on the label. You should never base on a mixing ratio recommended by a different manufacturer other than the one for the specific product you want to use.

It is important to note that 2,4-D will kill not only weeds on your lawn but also any broadleaf plant, including flowers, shrubs, and trees. When used in excess, this herbicide may harm your grass. Signs of excessive application of 2,4-D on your lawn include:

  • Brown or dead grass.
  • Bleached-looking grass.
  • Dry grass that shows signs of drought stress.

Make sure to follow the manufacturer’s instructions on mixing and the area to be covered. For example, if the specifications are 2 gallons for 1000 square feet, applying the 2 gallons for 500 square feet will be an over-application, while using 2 gallons for 2000 square feet will be an under-application and may not kill weeds as intended.

2,4-D Mixing Instructions

When applying 2,4-D, adhere to these guidelines

  • Add a surfactant – you can either use a commercial surfactant or use dishwashing soap. Adding a surfactant enhances the weed killer’s effectiveness as it is able to stick to the weed leaf or blades. For commercial surfactants, follow manufacturer guidelines, while for dishwashing soap, use one teaspoon of dishwashing per gallon of water. The surfactant should be put first into the sprayer before adding water for effective mixing.
  • Add the right amount of 2,4-D per gallon of water as specified by the specific product manufacturer.
  • Always wear protective gear before mixing and during the application of the herbicide.

When should I spray my lawn with 2,4-D?

Growing a dense lawn requires regular maintenance, like mowing, watering, and controlling weeds. Killing weeds with 2,4-D requires proper timing, as applying it at the wrong time could be ineffective. To maximize the effectiveness of 2,4-D, do the following;

  1. Apply 2,4-D weed killer in early spring or fall – Like other herbicides, 2,4-D works best when weeds are actively growing. Applying 2,4-D during winter will be ineffective because the weeds will also be dormant. High temperatures during spring and summer will increase its effectiveness. The temperature should be between 60-85°F.
  2. Spray on a calm day with no wind or when the wind speed is below five mph. Wind will blow away the weed killer causing the unbalanced distribution of the herbicide.
  3. Do not spray shortly after or before rainfall. The rain will wash away the herbicide before it penetrates the weed system and kills it. Wait for at least 24 hours after a rainy day before applying 2,4-D and check the weather forecast to make sure it won’t rain for the next 24 hours after application. It is okay to apply on wet soil but not on wet blades.
  4. Do not mow immediately after applying 2,4-D. Weed killers work best on actively growing weeds. Mowing causes stress to the lawn, including the weeds, and applying it immediately after mowing will be ineffective. Also, mowing immediately after application will remove the weed killer before the weeds absorb it. Wait for 4-7 days after the application of a weed killer to mow the lawn.

How long does it take for 2,4-D to work?

2,4-D takes up to 14 days to completely kill broadleaf weeds on the lawn, but you will start seeing results in the first 48 hours. Most fast weed-killing herbicides, such as Roundup, are nonselective and will kill even grass if they come into contact with it.

Although 2,4-D will take longer, it will not hurt the grass unless applied in excess. Below are other reasons why most lawn owners choose 2,4-D.

  • It kills many broadleaf weeds
  • It is selective and will not harm the lawn grass.
  • It is safe to use on most turf as long as it is applied appropriately.
  • It has a high rate of killing weeds.

If you use the right ratio when mixing 2,4-D, it will kill all the broadleaf weeds on your lawn. It will take a maximum of 14 days to kill the weeds, but it will stay on the soil for about a month. In case it does not kill all the weeds, wait for 30 days before applying again. Applying before 30 days could damage the grass.

Note that, applying too much herbicide on your lawn will kill helpful microorganisms in the soil resulting in thatch buildup. However, after applying the right amount of 2,4-D, you will start to see the weeds brown and wilt in the first 48 hours.

Final Thought

The best time to apply 2,4-D is midday in early spring or fall when the temperatures are between 60-85°F. Ensure the lawn is dry, and avoid applying on a rainy or windy day, as the herbicide will be washed or blown away. Also, do not mow immediately before or after the application.

It is essential to follow manufacturer instructions on mixing ratio and use a surfactant to help 2,4-D stick on the leaves or blades of the targeted plant for an effective outcome.


  1. United States Environmental Protection Agency, 2,4-D
  2. National Pesticide Information Center, 2,4-D General Fact Sheet
  3. Wikipedia, 2,4-Dichlorophenoxyacetic acid

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