Hi, I just moved into a new house with an empty backyard, so I added grass seeds and lawn feeder after tilling it. I didn’t do any weed treatment, and now I see crabgrass growing alongside the lawn grass. Is there anything I can use to kill the crabgrass without affecting my lawn grass?
You can easily kill broadleaf weeds. Any broadleaf weed killer will work for crabgrass. Use a liquid herbicide with at least three of these ingredients: 2,4-D, dicamba, MCPP, MCPA, triclopyr, fluroxypyr, and sometimes quinclorac.
For example, Ortho Weed B Gon is a weed killer that fits these criteria and is available at hardware stores.
Someone suggested mesotrione with a non-ionic surfactant, which is another good option, but note that follow-up applications are often needed with that one.
In your pictures, I don’t see crabgrass, but there may be a type of grass that wasn’t planted on purpose. I can’t identify it for sure without clearer pictures showing the roots and collar region. Just hope it’s not quackgrass.
@Jesse
Definitely listen to Niles… he knows what he’s talking about.
The photo shows the area of the lawn with the worst weed problem. There are other spots without the weed. I don’t want to damage everything—are there other options?
Does that plant look like cilantro?
Does that plant look like cilantro?
Yes, there seems to be a clover-like plant in there as well, plus something else I’m not sure about.
Just telling someone to start over if they have a weed isn’t helpful.
Try using mesotrione. I buy the Tenacity brand.
Spectracide Weed Stop for Lawns + Crabgrass (make sure to emphasize the ‘For Lawns + Crabgrass’ part) is a solid product you can find at Home Depot or Lowe’s.
However, depending on air and soil temperatures now in the North, treating weeds might not work well since the plants won’t absorb it properly. For example, around 45 degrees Fahrenheit seems to be the limit for this product.
Regardless of whether you treat with a post-emergent now, be sure to apply a pre-emergent in the spring to stop new crabgrass and unwanted weeds from coming back.
What I understand is that crabgrass is an annual. You should apply a pre-emergent before its seeds germinate in early spring. Then, shortly after, apply weed and feed for the lawn. Wait a month before overseeding your grass. Keep the crabgrass cut short and prevent it from going to seed. After a couple of years of this, you should see a significant improvement.