Pre-Emergent Herbicides: When and How to Apply Them in Central Oregon

When it comes to maintaining a pristine lawn in Central Oregon, pre-emergent herbicides are a powerful tool in the fight against weeds. Knowing when and how to apply these products is crucial, especially in regions like Bend and Redmond, where the climate can pose unique challenges. This guide will walk you through the best practices for applying pre-emergent herbicides, ensuring that your lawn stays lush and weed-free.

Why Timing Matters

The effectiveness of pre-emergent herbicides hinges on applying them at the right time. These herbicides work by creating a barrier in the soil that stops weed seeds from germinating. If applied too late, after weeds have already sprouted, the herbicide won’t be effective. In Central Oregon, the best times to apply pre-emergents are:

• Early Spring (Late February to Early March): As temperatures start to rise and the soil begins to warm up, weed seeds will start to germinate. Applying a pre-emergent herbicide at this time will prevent common spring weeds like crabgrass from taking root.

• Late Summer to Early Fall (August to September): A second application in late summer can prevent fall-germinating weeds, such as annual bluegrass, from establishing themselves before winter.

Choosing the Right Pre-Emergent Herbicide

Not all pre-emergent herbicides are created equal. It’s important to choose a product that targets the specific types of weeds prevalent in Central Oregon. Some common options include:

• Prodiamine: Effective against crabgrass, foxtail, and other common grassy weeds.

• Dithiopyr: Provides both pre-emergent and early post-emergent control, making it a versatile option.

• Pendimethalin: Ideal for preventing a wide range of grassy and broadleaf weeds.

How to Apply Pre-Emergent Herbicides

Applying pre-emergent herbicides correctly is key to their success. Here’s how to do it:

1. Prepare Your Lawn: Mow your lawn to a shorter height and remove any debris. This ensures the herbicide reaches the soil effectively.

2. Use the Right Equipment: A broadcast spreader is the most efficient way to apply granular pre-emergents evenly across your lawn. For liquid formulations, a sprayer with a fan nozzle works best.

3. Follow Application Rates: Always follow the manufacturer’s instructions regarding application rates. Applying too much can damage your lawn, while applying too little may not provide adequate weed control.

4. Water It In: Lightly water your lawn after applying the pre-emergent to activate the herbicide. This helps it form a barrier in the soil where weed seeds are waiting to germinate.

Post-Application Tips

After applying a pre-emergent, it’s important to follow these tips to maximize its effectiveness:

• Avoid Disturbing the Soil: Activities like aeration can break the herbicide barrier, reducing its effectiveness. Wait several weeks before performing such tasks.

• Monitor Weed Growth: While pre-emergent herbicides are effective, they’re not foolproof. If any weeds do appear, remove them promptly to prevent them from spreading.

Conclusion

Applying pre-emergent herbicides at the right time and using the correct techniques is crucial for maintaining a weed-free lawn in Bend and Redmond, Oregon. By following these guidelines, you can ensure that your lawn remains healthy, vibrant, and free of unwanted weeds throughout the year. Remember, prevention is always better than cure—so get ahead of weeds before they become a problem.