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Reseeding and trimming #925366

Asked March 03, 2026, 3:28 PM EST

Hi- Thank you for your guidance for my 2 questions. 1- I've read that reseeding when the ground is 40 degrees or less is the ultimate time because it will grow early and I can still put down crabgrass pre-emergent. Today, I read that that is not true. What is your opinion? 2-I've been waiting to trim my yews and fir trees for the beginning of March. Is it still ok to trim even in these wild temperatures? Thanks so much!

Hennepin County Minnesota

Expert Response

Thank you for reaching out.

I think you could go ahead and put down seed.  It will germinate when the temps are warm enough. I would not put down any pre- emergent down.  In normal situations a rule of thumb is to apply crabgrass killer when the lilacs bloom, but with the temps not being normal that may be up in the air.

For grassy weeds, such as crabgrass, the best time to apply pre-emergent herbicide is in late spring or early summer. This is because these weeds germinate later in the season than other types of weeds.  You want the temps to be at a constant 50 degrees.

One other factor to consider is that applying both together may possibly prevent grass seed from germinating.

You can go online and get more information.

Yes you can go ahead and trim your yews and firs.

Deb Kroon Replied March 04, 2026, 5:46 PM EST
Thank you for answering my questions.

On Wed, Mar 4, 2026 at 4:46 PM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied March 04, 2026, 6:10 PM EST

You're welcome!

Deb Kroon Replied March 04, 2026, 7:48 PM EST

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