Question
QUESTION: i believe we have the same problem that Kenneth Joergensen answered in 2004 about unwanted bent grass.  i have had a great 3/4 acre lawn for nearly ten years. on the same advice that ken gave, my local golf course manager examined and agrees with him. we have started the eradication process using round up - the area keeps getting larger. as we look around we seem to find more and more areas where little patches are starting to develop.  are there other ways to stop this from happening?  where does it come from? is there another method or herbicide to control these smaller areas? will reducing watering next year help top kill off these areas and let the ryes, fescues and kentucky's take over again?  it is starting to get colder here in Michigan, can i still put the new seed down this year? This is starting to be a much larger job than originally thought. thanking you in advance, mike

ANSWER: Hi Mike,

I do deal with this one regularly.  Honestly, all you can do is keep at it.  Each year, plan on spraying the bentgrass with Roundup in about August and reseeding in September.  My only advice to simplify things would be to use a core aerator instead of ripping out the dead stuff.

http://www.thelawncoach.com/Past_Columns/Entries/2008/8/12_Bentgrass_is_Best_Lef

The above link is to a column I wrote a while back on this very topic.  Take a look.  I think it'll explain your procedure well.

Here's the thing to keep in ming though.  After a few seasons, you should be all set with only the occasional little patch popping up here an there.  If you keep in top of those with a small roundup spray can, you should be all set.

Good luck and keep at it!

C.J. Brown
www.thelawncoach.com

---------- FOLLOW-UP ----------

QUESTION: I am using Round Up (red cap)as the medium for mass bent grass destruction. This new product shows results within 12 hours seems to be killing it off.  Am I on the right track?  How long should i wait before seeding?  I do not want to waste all this seed if it will not grow.  I do own a core machine b/c I aerate on a regular basis.  It still puzzles me of where this all came from in the first place. Again, thanks for you added help.   Mike in Michigan

Answer
Hi Mike,

I'd give it a week before re-seeding.  The roundup tends to dissipate quickly, and usually needs to be absorbed by the leaves in order to work.  This is why seed isn't too threatened (no leaves yet).  That said, if you spray the seed directly, you'll probably have some problems with growth and germination.  That's why I recommend at least a week wait.

As to where it all came from?  I can't say for sure, but I do know that bentgrass seed used to be one of the varieties in a standard home lawn mix.  It was a while before they realized that it didn't blend well, but by then many people had very patchy lawns.  You've probably got some that has been lingering and surviving ever since.

-C.J. Brown
www.TheLawnCoach.com