Removing dead crabgrass?

[Teoteodore]

I may have made the mistake this year of overseeding at the expense of pre-emergent. I've used crabgrass killer recently with pretty good (not 100%) success, but now I have many, many large patches of dead crabgrass. Should I remove the dead grass --- if so, is there a mechanical means rather than hand pulling? Should I leave it to rot until Spring? If I do remove it now, should I overseed?

 

[oneeye]

I may have made the mistake this year of overseeding at the expense of pre-emergent. I've used crabgrass killer recently with pretty good (not 100%) success, but now I have many, many large patches of dead crabgrass. Should I remove the dead grass --- if so, is there a mechanical means rather than hand pulling? Should I leave it to rot until Spring? If I do remove it now, should I overseed?

You can kill the mother plant, but it doesn't do anything about the seeds left behind. If you look closely at the dead seed bracts, you will see the main problem. Crabgrass seed can remain viable for up to 15 years. That means you have millions of seed from the past years which is the problem. The best time to deal with crabgrass is in the beginning and not the end of the Season. This is why many people give up after a few years of trying.

To kill crabgrass before the seed sprouts apply a pre-emergent herbicide like prodimain or dithiopyr in early spring when the temperatures get up to 50-55°F. You have to be diligent and stay with it. Watering in the product into the soil to create a shield that stops seeds from germinating. Some people swear that using corn gluten meal as an organic pre-emergent works, but I have never had good results with that product. There's no machine that will remove crabgrass seed. Good luck friend.

A crabgrass plant can produce up to 150,000 seeds in a single season, and those seeds can remain viable in the soil for years. This creates a large "seed bank" that can cause problems for many seasons to come. AI

 

[cpp gardener]

To remove dead crabgrass you will have to hand pull. The pre-emergent will kill most of the seeds next year as they sprout. If you want to reseed the lawn with desirable grass, you need to do it before you use the pre-em. Allow about a month before applying the pre-em to let the good grass grow.