How Long After Seeding Can You Spray For Weeds?

You just planted a new batch of grass seeds. Unfortunately, the weeds are starting to sprout up along with the new grass. Does spraying weeds kill the seeds?

Killing weeds in newly seeded lawn is a concern for many homeowners. There is a time and a place for weed killer, but your fragile grass seeds and seedlings are not it! Keep reading to learn more about when to apply weed control in brand new grass.

What’s the best timing for weed killer after seeding?

The general rule of thumb for an application of a broadleaf weed killer, such as 24d, is to wait at least until you have mowed the new grass at least four times. Avoid applying a pre-emergent to a newly seeded lawn for at least 3-4 months.

What’s the best way to control weeds with new seeds?

Unfortunately, no one can keep the weeds at bay while new grass grows strong and hearty. However, there are ways to prevent and control weeds in a newly seeded lawn!

Apply precautionary weed killers

Spraying Dandelions

Have you heard the saying, “An ounce of prevention is worth a pound of cure?” This saying applies to weeds, as well!

If you are applying grass seed for a new lawn, apply a non-selective herbicide 7-14 days before preparing the soil for the new seeds. If there are still weeds after 14 days, use a second herbicide application, then wait another seven days. After a week is up, till the soil and apply the grass seed.

For overseeding, apply a weed and feed fertilizer 7-14 days before you plan to overseed the lawn. Always check the label for application instructions. Water the area thoroughly.

Choose grass seed carefully

Many grass seed varieties contain up to 1 percent of weed seeds mixed right in with the grass seed. It is important to choose a high quality grass seed that is 99.99 percent seed, without any weeds or fillers. This will give you fewer weeds to worry about.

Apply mulch

Mulch may help protect new grass and prevent emerging weeds. It is essential to pick the right mulch, however! Grass seeds can be covered with straw, peat moss, plastic, fabric, grass clippings, or other types of mulch. A thin layer is best in order to allow water and sunlight to reach the grass.

Pull weeds by hand

Sometimes you just have to roll up your sleeves and get your hands dirty. Keep a close eye on the new grass and pull weeds as soon as you see them! Be careful not to walk on the newly seeded area.

Pull weeds by hand

Keep the grass healthy

Healthy grass will fill up the space and leave no room for weeds. Keep the grass healthy with new grass starter food and regular watering. Water the seeds every day until they germinate. Once the seeds sprout, reduce water to every 2-3 days.

Put up a temporary fence to keep foot traffic to a minimum while the grass is getting established.

What about crabgrass?

You may ask, how long after seeding can I use a crabgrass preventer? The same rule still holds true! Wait until you have mowed at least four times before applying any herbicide to a new lawn.

Final Thoughts

New grass and grass seed requires a bit of care in its early days. Make sure you understand how to care for your new grass! Avoid herbicides until the grass is well established. In the meantime, use mulch and pull weeds in order to keep the space free for new grass to establish roots and grow healthy and strong.