Killing Weeds in Newly Seeded Lawn (Weed Control for New Grass)

Published Categorized as Lawn Weeds

DOES YOUR newly seeded lawn have weeds? It is quite alarming and disappointing! These undesirable plants make the grass messy as they consume the nutrients that new turf requires for growth. Various weed killers can help eliminate weeds. Unfortunately, these herbicides cause more harm than good to the new turf. So, if you need to know about weed control for new grass, keep reading.

The best weed control for new grass is pulling them out by hand, mowing, or using a selective pre- or post-emergent herbicide. Additionally, applying new seed fertilizer, specifically NPK, with weed preventer during seeding can effectively help in killing weeds in new grass. Pulling out weeds before seeding or once the turf develops deeper roots is another way of weed control in new grass.

Weed Killer for New Grass

Killing weeds in newly seeded lawns using herbicides can cause irreparable damage to your new grass. The turf is delicate, weaker, and cannot withstand the harsh chemicals meant to kill undesirable plants.

For instance, pre-emergent weed control herbicides interfere with any sprouting plants and can kill the grass seeds. On the other hand, post-emergent herbicides kill new grass and weeds. Therefore, avoid applying weed killer on new grass unless the herbicide is specifically for use during seeding.

How to Control Weeds in a Newly Seeded Lawn

Weed Control for New Grass

One of the mistakes you will do when dealing with weeds on a new lawn is to apply homemade or premium herbicides.

Never use moss, feed, and weed killer on your new grass because the weeds, however healthy they may look, have not taken root.

Although there are a few selective herbicides that you can use, it is advisable to pull the weeds out by hand at this point.

Alternatively, you can watch the weeds grow alongside the new grass until the grass attains 6-8 weeks, during which, you can now mow the grass to suppress the weeds.

NB: Pulling new weeds will also pull out the new grass.

However, if the weeds continue to thrive after pulling them out by hand or mowing the grass, do the following:

1. Use a selective weed killer for new seeded lawn

Weed Control for New Grass

The best grass seed weed killer for new lawns is a selective product like Tenacity Herbicide (pictured above). Use it as a pre-emergent during seeding as it contains Mesotrione which acts as a crabgrass preventer and killer.

You can also use Tenacity post-emergently as a new grass weed killer. However, you must mow the new turf thrice before using the herbicide. Quinclorac is another great weed killer on new grass, but you must only spot-treat the new weeds.

2. Use new seed fertilizer with weed preventer

Most lawn professionals recommend using a starter fertilizer, precisely the NPK one, with a weed preventer to control weeds in new lawns. For instance, you can use Scott’s Turf Builder when seeding, as it has a weed preventer. The fertilizer contains Mesotrione which provides at least one month of weed control.

Key Takeaways

*** Avoid using a Weed, Feed, and Moss Killer chemical on a newly seeded lawn

*** Pull out any weeds in a new lawn by hand as they’ll be shallow rooting

*** You can wait for the lawn to establish for at least 6-8 weeks before mowing them out

*** For the persistent and reoccurring weeds, spot-treat them with a selective herbicide

Frequently Asked Questions (FAQs)

Q: Should I plant grass seed or kill weeds first?

A: You must kill the weeds first before planting grass seeds or sod. Lawn care professionals recommend controlling any undesirable plants and weeds in the lawn using a non-selective herbicide before planting seeds. However, you should do this at least two weeks before planting.

Q: Which is the Best Weed Killer Before Seeding?

A: The best weed killer to use before seeding is glyphosate. It is a non-selective, post-emergent herbicide that degrades once in contact with the soil and leaves no harmful residue. The best time to use it is from April to September, then plant the seeds a few weeks after application.

Final Thoughts

It’s alarming to see weeds infesting your newly seeded lawn, as they can cause severe damage to your grass. Although there are several herbicides to control weeds, the chemicals can do more harm than good for the new turf.

To carry out weed control for new grass, use a selective herbicide as pre or post-emergent. You can also pull out existing weeds before seeding or once the grass develops deeper roots. Besides, new seed fertilizer with weed preventer is another great weed killer for new lawns.

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By Wycliffe Magara

Hi, my name’s Wycliffe Magara, a professional landscaper, journalist, published author, photographer, and lawn attendant. Apart from this site, I also own LawnAffection, Grasstology, and TheScholarshipTipster. I specialize in creating informational content to help you grow a Lifelong Lush Lawn and find the ideal scholarship opportunities no one ever talks about.