How to use Prodiamine for pre-emergent weed control: A complete guide

Weed control is essential for maintaining a tidy, healthy outdoor space. A good way to prevent weeds from germinating in the landscape is by applying a pre-emergent like Prodiamine. Rather than waiting for weeds to pop up and spraying them, Prodiamine prevents weed seeds from growing in the first place.

Weeds will take over a yard or garden if left uncontrolled. They take away water, sunlight and nutrients from grass and other plants. Once weeds start growing, they can be hard to remove without harming the plants nearby. This is where the best pre emergent herbicide for lawns, prodiamine, comes to aid. It stops weed seeds from sprouting, which gives the lawn and garden a better chance to stay healthy.

Prodiamine Profile

Prodiamine is a product for weed control called a pre-emergent herbicide. It is a member of a class of chemicals known as dinitroanilines. These chemicals inhibit weed seeds from growing roots and shoots that would allow them to become full-blown weeds.

The active ingredient of Prodiamine appears yellow and has low solubility. It doesn’t penetrate deep into the soil, where most of the seeds of invasive grasses germinate. It’s slow to decompose and can remain active in the soil for an extended period of time, sometimes months.

Mode of Action in the Soil

Prodiamine prevents cell division in the young roots of weeds. When a weed seed begins to germinate, its cells must divide and grow to send roots down into the soil. Prodiamine inhibits this action. It never breaks dormancy, so the seed cannot grow roots or shoots and the weed dies before it breaks dormancy and can be detected. The product won’t work as intended if it’s applied after weed seeds’ germination and the application area is not watered in afterward.

Spectrum of Weeds Controlled

Prodiamine is a selective pre-emergent herbicide for the control of annual grasses and broad-leaf weeds. Some of the weeds controlled by all-in-one weed killer are:

• Crabgrass
• Goosegrass
• Chickweed
• Poa annua (annual bluegrass)
• Spurge
• Henbit

Timing and Environmental Factors

Timing is everything when it comes to Prodiamine. This herbicide operates before weeds germinate, so it has to be applied at the proper time relative to soil temperature and weather.

Prodiamine Application Timing

There are two primary application times for prodiamine:

• Spring Application

The goal in spring is to prevent summer weeds such as crabgrass, goosegrass and foxtail. Spring Prodiamine should be applied when the soil temperature is below 55°F. A good way to check timing is to use a soil thermometer or look for forsythia flowers blooming, which is a natural sign that it’s time to apply.

The user can also judge by looking at the Growing Degree Days (GDD). Prodiamine is most effective when GDD units reach approximately 100-200 using a 50°F base temperature.

• Fall Application

It helps prevent winter weeds such as annual bluegrass (Poa annua), chickweed and henbit in the fall. Use it when soil temperatures begin to drop to 65–70°F, typically late summer or early fall.

Soil Temperature and Water

To perform properly, prodiamine requires the right soil conditions. It does not, unlike some other weed killers, operate through the leaves. Instead, it needs to be watered into the ground where seeds of weeds are waiting.

Soil Temperature

The right soil temperature is important.

• Apply in spring when soil temperature is 50°F – 59°F.
• In the fall, when it cools down to 65°F to 70°F.

Soil temperature can be checked with a thermometer pushed into the ground. The air temperature is not accurate enough.

Soil Moisture

Lawn should be watered 0.5–1 inch of water after application of Prodiamine. This helps push the product into the soil where it can kill the weed seeds. The water can come from rain or from irrigation, but a heavy rain is liable to wash it away, so timing is significant.

Weather and Location Tips

Your  geographic location and what type of grass covers your property has a lot to do with prodiamine application timing.

Cool-Season Grasses

Cool-season grasses like fescue, bluegrass, and ryegrass are common in northern regions (like USDA zones 3 to 6).

• Apply Prodiamine in early spring to stop summer weeds.
• Apply again in late summer or early fall to stop winter weeds.

Important: Do not use Prodiamine where new grass seeds will be planted soon. It can also prevent them from growing.

Warm-Season Grasses

Warm-season grasses like Bermudagrass, zoysiagrass, and St. Augustine are found in southern regions (USDA zones 7 to 10).

• Apply in late winter to early spring before summer weeds appear.
• A second application in the fall helps control winter weeds.

Regional Guidelines

• Northern U.S. and Canada: Apply in March–April, and again in August–September.
• Southern US: Late February–mid March and again mid–late Sep.–Oct.
• Coastal regions: Look out for longer growing seasons and warmer winters. Adjust timing based on local soil temperatures.

Calibration and Equipment Preparation

Applying Prodiamine correctly with the proper equipment is crucial for beautiful results.

Choosing the Right Equipment

There are different tools for applying Prodiamine, depending on whether it’s a granular or liquid product. Each tool has its benefits and drawbacks.

1. Drop Spreaders

• It drops the product vertically, in a tight column.
• Best for small lawns or edges where precise control is required.
• Precise, great for small places.
• Slower to cover large areas. There are potential dead spots if people don’t overlap properly.

2. Rotary Spreaders (Broadcast Spreaders)

• It’s a wide arc spreader, so as the user pushes it, it will disperse the granules.
• For medium to large lawns.
• Fast coverage, best for wide open spaces.
• Less precise. Granules can blow off target in the wind. Needs overlap to avoid stripes.

3. Sprayers (for liquid Prodiamine)

• It combines Prodiamine with water and spreads it consistently over the lawn.
• That could be a hand-held pump sprayer, a backpack sprayer or a dolly tank sprayer.
• Even spread, easy to apply to large or uneven lawns.
• It must be calibrated carefully. Mixing must be done properly. Requires protective gear.

Tip: The choice depends on size of lawn, personal preference and whether the product is a liquid or granular form.

Calibrating Spreaders and Sprayers

Calibration will confirm the appropriate amount of product intended to be applied. Overuse can damage grass, while underuse may not halt weeds.

Spreaders

1. Check the label of the Prodiamine product to determine the recommended application rate (usually in pounds of product per 1,000 square feet).
2. Measure of a 1,000 sq ft section of the grass.
3. Measure the right amount of granules.
4. Apply to the unglazed test area with the spreader set at the desired setting.
5. If users run out early or have extra left, adjust the dial and repeat until it’s accurate.

Sprayer (Liquid)

1. Test the sprayer with nothing but water.
2. Draw a 1,000 sq ft on a level floor.
3. Applying spraying evenly over the ground as the user walks at a steady pace.
4. Measure how much water it took to cover that area (a catch-can test can be performed by placing small containers throughout the area to collect and measure output).
5. Use this amount to mix the right amount of Prodiamine with water based on the label instructions.

Calibration is very quick but can have significant effects on the outcomes.

Mixing and Handling Protocols

Applying Prodiamine safely involves some common-sense rules of mixing, measuring and protecting yourself.

Safety Gear

• If ever use the weed killer, make sure to use gloves, long sleeves, closed toe shoes etc.
• When spraying liquid Prodiamine, wear eye protection and maybe a dust mask, especially on windy days.

Mixing Ratios

• Follow the label instructions closely. Liquid Prodiamine often comes with a range (e.g., 0.4 to 0.83 oz per 1,000 sq ft).
• Mix only what is needed for one job to avoid storing leftover product.

Water Volume

• For liquids, the water amount doesn’t matter as much as the product amount, as long as it applies the full solution evenly over the right area.
• One common rate might be 1 gallon of water for every 1000 square feet, although this will vary depending on the sprayer.

Agitation and Mixing Tips

• Agitate or stir the solution in the tank while mixing and applying to keep the product in suspension.
• If using granular Prodiamine, just make sure the granules stay dry and are not clumped together before use.

Clean up equipment after application of Prodiamine (as it may harm or seal the equipment) and prevent future physical damage or leftover chemical residue. Spray or spreader should be rinsed, cleaned with water and allowed to dry.

Prodiamine 65 WDG Instructions

In order to achieve the best results with Prodiamine, prodiamine 65 WDG instructions label need to be followed. Here’s how to determine how much to apply, spread it evenly and water it in appropriately.

Calculating Application Rates

It is crucial to apply the right amount of Prodiamine to make sure that it performs properly. Too much or too little can be a problem for turf and weed control. Application rates will vary by label and may be listed in one or more of the following units: Pounds per 1,000 square feet (lb/1,000 ft²) or kilograms per hectare (kg/ha).

Rates vary based on the type of turf, composition of the soil and the weeds people want to control. For instance, a typical rate might be 0.5 to 1.5 lbs/acre, or 0.5 to 1.5 oz/1,000 ft² for granular materials.

To set a spreader correctly:

1. Measure the space to be treated (length × width in feet).
2. Measure the appropriate quantity of product (e.g 1 lb.)
3. Use the spreader on a low setting.
4. Do a test on a small area (200 or 500 sf).
5. After practice testing, see how much was used. Set the spreader if necessary.

For liquid products:

• Dilute product according to label directions (e.g. 1 oz per gal of water for 1,000 sq. ft.).
• This can be done with a hand pump sprayer, a backpack sprayer, or even a motorized boom sprayer.

Uniform Coverage Techniques

Even coverage is essential. Small areas will leave space for weeds to grow, while too much can damage the lawn.

• Walk at a consistent pace of about 3-3.5 mph (a brisk walk) to ensure an even application.
• Spread the product over the section, overlapping a bit so there are no empty spaces.
• Do it once north to south and then again east to west. This ensures even coverage.
• Do not apply on windy days (granular or liquid application may blow off the target).

Always wear the correct personal protective equipment (PPE) when applying.

Post-Application Irrigation

Prodiamine has to be watered in properly for it to work. Water within 24 hours after application, or better yet immediately after. Watering immediately prevents the product from being blown or trampled away. 

Use 0.5 to 1 inch (1.2- to 2.5-centimeter) of water to push the product into the upper soil layer. This water contributes to forming the protective cover that prevents weeds from germinating.

• Don’t add too much at once since expanding it is a delicate process and it can easily run off and/or pool, washing the product away.
• All granular products require very light watering to dissolve them and move the herbicide to the soil.
• Suppose rain is on the way; no need to water. Just make sure it rains so the material is hydrated.

Safety and Regulatory Compliance

It is very important to use Prodiamine safely. This section explains the safety gear needed, what to look for on the label, and how to protect the environment during use.

Personal Protective Equipment (PPE)

When using Prodiamine, make sure you wear appropriate Personal Protective Equipment (PPE) to protect yourself from the chemicals.

• Gloves: Prevent skin from coming into contact with the herbicide.
• Goggles or Face Shield: Preventing the eyes from being splashed which leads to irritation.
• Long-Sleeve Clothing and Pants: These help protect the skin from accidental exposure.
• Respirator: A respirator may also be necessary to avoid breathing dust or mist (powder forms only).

Each of those things helps keep the chemical away from the skin, out of the eyes and out of the airways.

Label Requirements and Record-Keeping

The Prodiamine label has all the details users need to use it safely and within the law. It’s essential to read and adhere to the label directions.

• Rates of application: The label will indicate how much product to apply per area to maintain effective control of pests without damaging the lawn.
• Timing: The label will give the optimal time to apply the herbicide, according to weather and soil conditions.
• Re-entry intervals: This indicates when it is ok to re-enter the area that was treated.
• Limited access: Depending on certain products, one might need to remain off treated areas for some time.

Record dates, locations and applications of Prodiamine. This is to ensure smoothness against local laws. Record the date of application, the amount applied, the spreader settings or sprayer type and weather conditions at the time of application. These records may be required for adherence or if there’s a concern with the treatment.

FAQs

How to apply prodiamine pre-emergent?

Prodiamine pre-emergent should be applied before weeds begin to germinate. Usually it’s in early spring or in the autumn, when the soil temperature is right.

What is the mixing ratio for Prodiamine?

Mix rate on Prodiamine is up in the air, but users often see 1oz per gallon of water per 1,000 sq ft.

Do you put Prodiamine on first or fertilizer?

Apply Prodiamine first, then wait a few days before applying fertilizer to avoid interference with its effectiveness.

The Bottom Line

Prodiamine is an excellent option for shutting down weeds before they even germinate. Many weeds can be halted from growing in one’s lawn or garden by applying it at the right time, usually in early spring or fall. For people seeking quality lawn care with prodiamine, Growcycle has solutions for healthy and weedless lawn maintenance.

Disclaimer: This material is for informational purposes only and should not be relied on for legal, medical, financial, or any other form of professional advice.

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About the Author

Victor Miller

Environmental Journalist Focused on Sustainable Agriculture

Victor Miller is an environmental journalist at Growcycle, specializing in sustainable agriculture. With a passion for storytelling, he highlights the latest trends, innovations, and practices that promote ecological balance and responsible farming.