When to Apply Crabgrass Preventer

The sight of crabgrass makes you wonder when to apply crabgrass preventer. Crabgrass is a common weed yet the most stubborn to kill. Even though it is not harmful, crabgrass existence aches like heartbreak, especially when it grows on a lush lawn. Bear in mind that crabgrass elimination will not be an easy kill. Be ready for an uphill task, but doable.

As timing is crucial in this ‘operation prevent crabgrass,’ you should be alert on the perfect time for take-off. This is because crabgrass produces many seeds that, if left to germinate, they will be a significant nuisance to the gardener.

This article will help you dig in for more on crabgrass prevention tips. Read on.

When to Apply Crabgrass Killer

In weed killing, crabgrass inclusive, timing is everything.

Nevertheless, three basic things will enable you to know the perfect time to apply crabgrass pre-emergent herbicide. A pre-emergent herbicide is the same as a preventer herbicide since it prevents the weeds and unwanted grass from germination. It kills the weed before it sprouts and develops roots. The three factors include;

Season: As a warm-season annual grass, early spring is the perfect season to apply crabgrass preventer. Why? This is because; during spring, the temperature is rising and heating the soil ready for germination. Generally, it is hard for plants to grow in cold soil conditions. This falls from late March to early April. The best application of the pre-emergence preventer for crabgrass should be after the 4th mowing to protect the lawn all through the growing season.

Soil temperature: The soil temperature ideal for crabgrass pre-emergence application should be about 55-60 °F, which lasts from spring to mid-summer. This temperature is warm enough to accommodate the germination of most plants, including the crabgrass. The warm soil activates the plant enzymes, which arouse seed germination.

However, it may be in March, but the temperatures are not yet warm due to climatic variations, shade, and wind where you reside. Therefore, be on toes to test the soil temperatures immediately after March sets in.

But if determining the soil temperature is challenging, look around for any weeds sprouting in your driveways and sidewalks. If they are visual, the crabgrass germination is on hence the best time to apply the pre-emergent. Preferably, apply the crabgrass preventer in the morning hours when the temperatures are COOLER than 90°F since high temperatures render them inactive.

Before or after the rain: The perfect time to apply a crabgrass preventer is before it rains. After the rains, the pre-emergence will soak into the soil through to the crabgrass seeds to prevent them from germinating and forming roots.

If you happen to miss the rains and apply after, water your lawn straight away to wash the crabgrass preventer into the ground. However, be wary of applying crabgrass preventer too early as it will be unproductive. If you miss the perfect application window, use the necessary herbicides to kill the sprout crabgrass.

Many practical crabgrass pre-emergent herbicides suggest that you should water your lawn a couple of days after application. This way, the concentration will soak into the soil.

Tip: Be keen on your daily local weather forecast to know when it will rain. In case the rains will pour in 3 hours, apply the pre-emergent herbicide immediately. If it does not rain and the preventer is on the soil, wait for 2-3 days to water your lawn to wash the preventer into the ground. 

The pre-emergent lasts for a maximum of 4 months, depending on when you chose to apply and the number of applications you will need.

Should I Mow Before Applying A Crabgrass Preventer?

The unwritten rule says that you should apply a pre-emergent herbicide to lawns over a year old. An older yard is ready for mowing. Mowing a fresh lawn will kill the grass seedlings.

Mowing before applying a crabgrass preventer helps maintain an even lawn surface. Thick and uneven patches will hinder the spread of the pre-emergent herbicide. Since the herbicide will not get to the entire lawn because of the hindrances, some seeds will escape and germinate. What’s more?

Regular mowing will help the grass growth to allow the pre-emergent to spread evenly throughout the entire lawn. Mow your lawn at least three times to 3 inches short before applying the crabgrass preventer. A leveled yard enables watering the chemical effects to get into the soil. The water and the chemical will run smoothly through each blade and into the ground, working excellently.

Moreover, a well mowed and maintained lawn encourages healthy grass growth. Healthy grass growth advances a well-aired soil layout that allows water and pre-emergent herbicide to spread evenly throughout the yard. With the pre-emergent spread throughout, the weeds will have no escape route for germination.

Sharpen your mower’s blade to make precise cuttings. Split stems are prone to infections, and the crabgrass preventer will damage them further. Precise cuts promote healthy and normal grass growth and accord with an herbicide of choice.

Moreover, once you apply the crabgrass preventer on a well-maintained lawn, do not mow until the herbicide gets into the soil. Trim After the rains or after you have watered to wash out the pre-emergent deep into the ground. Cutting immediately after application will eliminate many of the crabgrass preventers even before reaching into the soil. That is zero work. Mow, preferably after three days after application and the herbicide washed into the ground.

Can You Apply Pre-Emergent In The Rain?

The best time to apply a pre-emergent is a few days before the rain. Also, you can water down the herbicide into the soil a few days after the rains. Rain is essential for the pre-emergent to work correctly. A pre-emergent herbicide should work on the earth and not on the soil. Therefore, water is necessary to wash out the herbicides from the plant into the ground. It will only inhibit germination when it is on earth. Read on.

After considering the preceding, the crabgrass preventer is not ideal on already wet grass. The wetness in the grass will dilute the herbicide even before it works its way into the soil. Even if water still dilutes while washing it into the ground, the already wet grass will make it more dilute. This way, it will be less effective and weak when it gets into the soil. A pre-emergent herbicide needs a few days on dry grass before washing out into the ground.

Note: Like all pre-emergent herbicides, avoid windy and rainy days of application.

Final Thoughts

When dealing with any pre-emergent herbicide, timing is vital for excellent results. The type of weed will determine the perfect time for the application of a weed preventer. Most pre-emergent lasts for a maximum of 6 months; hence require twice a year application. This means they will inhibit weed seeds germination for a long time before the next application. However, be careful not to use the ones that will discourage your useful grass from growing.

Otherwise, the best weed preventer is a healthy lawn. If facing a crabgrass problem, revise and improve your lawn care routine, a lush lawn that will keep away the weed infestation.

Always read and understand the dosing instructions, using, storing, and disposal of a pre-emergent herbicide and have protective gear on when using it.