Skip to content

How Long For Atrazine To Work

If you have a weed problem on your lawn, Atrazine is a popular herbicide that can be sprayed on your lawn to control annual weeds and broadleaf weeds. It’s a cheap chemical that works as a pre-emergent herbicide to prevent weeds from competing with your grass and crops throughout the growing season.

However, because of the safety of Atrazine contaminating drinking water and the dangers associated with its use, it can only be applied by a qualified applicator. Note that the European Union banned it.

Besides this, you may want to know how long does it take for Atrazine to work so your garden is safe for children and small animals. Because the toxin has to be absorbed by the weed’s roots after absorption by the leaves, it can take a long time, typically 15-20 days. (Read Banana Tree Roots Guide)

Atrazine herbicide for your lawn

The effective herbicide cuts off the plants food source, thus inhibiting photosynthesis where the weeds starve to death.

In this quick guide, you can learn about how long does atrazine take to work to kill crabgrass and other weeds. By the end, you’ll also find how to use it with liquid fertilizer and if it is a safe choice for preventing weeds.

What is Atrazine?

Atrazine is an herbicide that is mainly used to kill emerged weeds. However, it’s practical as both a pre-and post-emergent herbicide for home and agricultural purposes to control broadleaf and annual weeds.

In pure form, it’s an odorless, white powder that you can dissolve in water and use during the spring and summer months.

Is Atrazine Safe?

Atrazine is a highly popular but controversial herbicide used on emerged weeds. It can absorb into the body if you breathe it in, although it doesn’t stay there.

It leaves within 24-48 hours, mainly through your urine and feces, although a small quantity could enter your bloodstream should you come into contact with contaminated water or soil.

Because it’s good at killing weeds, there’s been a lot of research showing that its toxic levels get into the water and can be harmful to small animals like frogs, birds, and bees.

Atrazine doesn’t accumulate in live organisms like fish or clams; thus, it doesn’t harm the food chain.

Wear protective clothing if you are spraying your lawn and keep kids and pets away from treated areas until completely dry. (Read When Is It Too Cold To Water Grass)

When To Apply Atrazine to Lawn?

The best time to apply Atrazine is in the spring when grass greens up. This might happen anytime between February and April, depending on your region.

  • Greening up the lawn in the spring.
  • Between February through April, on average.
  • When temperatures are 65–90°F (18–32°C), apply because outside this, you’ll find Atrazine weed killer isn’t effective.
  • Apply Atrazine weed killers in the morning when temperatures are cooler and if spring afternoon temperatures are unusually hot.

How to Use Atrazine

When using pure Atrazine, dilute the concentrate in the amount of water specified on the label.

  • Hi-Yield Atrazine, for example, should be mixed at a rate of 4.3 ounces per gallon of water. The finished product will cover 500 square feet of the treated area.
  • Dilute Atrazine with the specified amount of water on the product label.
  • Spray your centipede grasses lawn with the Atrazine mix using a backpack sprayer, handheld sprayer, or hose-end sprayer with dilution controls.
  • Also, do not mix Atrazine with any other chemicals.
  • Atrazine should not be mixed with a surfactant since it penetrates the soil and attacks the roots.
  • Always spray Atrazine on calm days with no wind to safeguard other plants.

You can mix atrazine with 2-4-D and liquid fertilizer; just run a compatibility test first to ensure no undesired color, odor, or consistency changes.

How Long Does it Take for Atrazine to Kill Weeds?

Will Atrazine kill emerged weeds? Atrazine kills these weeds 14–21 days after application and does so by reaching the roots, then moving on to the leaves and disrupting photosynthesis.

Atrazine is taken up by plant roots and kills seedlings as they grow in the soil for approximately six weeks.

You can wipe out existing weeds and prevent new weeds from emerging for an entire spring season by applying Atrazine to grasses safe for Atrazine exposure.

Atrazine provides successful results as a pre-emergent and a post-emergent and is primarily used to control broadleaf and grassy weeds.

Atrazine selectively kills target weeds, interfering with the plants’ growth and causing the plant to die.

Atrazine works by interfering with photosynthesis. Photosynthesis— unique to green, living plants—happens when light energy is converted to chemical energy needed for food production stops, and then plants eventually starve to death.

Tips in using Atrazine to Kill Weeds

Spraying Atrazine

The time to observe benefits from an Atrazine spray varies depending on the type of weeds being targeted. Atrazine is a very slow-acting herbicide that might take up to 6 weeks after treatment for effective weed control.

Atrazine 4L Herbicide – This restricted-use herbicide is used to control weeds in turf grasses during the growing season.

Atrazine (4L) can control annual broadleaf and grass weeds in maize, sugarcane, and certain other crops, according to the label.

Atrazine is available in concentrated form. If you used it straight from the container, it would be a severe overload on your grass and its living organisms.

You’ll mix the chemical with ordinary water to make what you need for your lawn.

Before you begin, read the directions and safety precautions on the product label carefully. Make sure you know the size of your lawn, how long Atrazine needs for direct contact, and the weather conditions.

One gallon of water and 4.3 fl. oz. of atrazine are required for every 500 sq. ft. area.

Do not use Atrazine if you have a lawn that is not St. Augustine or Centipede grass. For example, if you have a Bermuda grass lawn, you should not use Atrazine for weed control.

How long does it take for atrazine to work before it stops?

The Atrazine active ingredient can stay in the soil for several days to several months after spraying on the weed.

The atrazine weed killer will remain in the ground for one growing season. Following then, it will be mostly broken down. (Read Raking Pine Needles Guide)

How long before rain should atrazine be sprayed?

For the best application and absorption to kill weeds, apply atrazine at least 1 hour before it rains in your area.

The best conditions to apply atrazine are when dry ground or leaves are slightly damp but not wet. Like other weed killers, don’t apply Atrazine if rainfall is forecast, as it will decrease the effectiveness.

How often can you apply atrazine?

Atrazine should only be used twice a year. Most experts advocate applying the first spray in January if you live in a warmer climate, so the weeds do not have time to recover from the winter.

When the harvest is over, and seeds are in the air, the second treatment of the weed killer should be made in November.

How does atrazine work?

By preventing photosynthesis, atrazine kills weeds. The roots of the weeds will absorb the weed killer.

The chemical will then spread to the tips of all actively growing leaves. Although there will be some absorption via the leaves, it will not kill the weed until it has passed into the roots.

You may be concerned about the herbicide’s impact on your other plants. But, on the other hand, you don’t want to destroy the rest of your meticulously manicured lawn.

All plants can absorb atrazine. The plants that atrazine does not kill will break down the chemical active ingredients before it affects photosynthesis.

How Long For Atrazine To Work