Assuming you're talking about Poa annua, any Poa battling has to be with Poa understanding. With spring pre-m I'm sure you prevented crabgrass and such, but it does nothing to prevent Poa because it does not germinate in spring. Just like any other bluegrass species, spring is Poa's growing season although there are other particulars about its life cycle that determine destruction despite your best efforts and even then, "best efforts" is still a relative subjective. The battle is more than once a year (which is all you did in effect) and it is more than one year. Moreover, winning the battle involves knowing just how effective the herbicide is on PA seeds to prevent germination and plants to prevent maturity. Most pre- and post-m products on the market have limited efficacy, which extends the battle onward. Once the plants are allowed to overwinter, grow in spring, and produce seeds, the battle starts all over again and previous efforts are rendered futile - ineffective - wasted. Furthermore, people have to make a choice of plans and understand that because battle and renovation coincide, efforts to do both have to be even more aggressive or decide on one rather than both, thereby opting to do the other at a later time.

I don't think so Best. I put out pre-m for fall 05 and fall 06 and then spring 06 and spring 07. I've applied pre-m spring and fall ever since I knew I had it. As far as pre-m goes, I doubt there is much more any one would propose that I haven't done.

I also dang near killed my yard last year in the summer trying to employ "cultural practices" that would favor the deeper rooted KBG over the poa annua. Despite all that, it seems to be holding its own. The bottom line is its just pretty tough and resilent.

Until they come out with a good poa annua specific herbicide, (besides the stuff only licensed applicators can put out) I think the best strategy is to put out pre-m spring and fall, don't water any more frequently than you have to... and get ready to not win the war.

I feel I am losing he battle myself. Last year was a boon for the poa annua. It was a very wet spring/summer--not at all hot and dry. The existing poa survived easily through until fall. And although I put down pre-emergent to cover spring through until fall, winter was unseasonably mild and I fear that some additional poa germinated during the mild December.

So as it stands, I have heavy investations, some unbelievably dense, and as much as 2 foot patches and very sparse showings here and there. The affected areas look gray from afar--solely due to the thousands of seedheads!

Plan: I am going to round up the large patches now. The seed that was already dropped hopefully will try to germinate this spring and be taken care of by Dimension (am about to put my 2nd application down now). I will try to patch these areas in the fall with the limited grass I've been able to grow in planters, and overseed the heavily affected areas as well (really only the very back of my backyard). So basically, my focus is on the large patches.

Hopefully a day will come when post-emergents like Prograss and Certainty will be easy and inexpensive to get so we won't have to worry about poa trivialis or poa annua.

It looks like i have more Poa Annua this spring than last year. I haven't really used pre-em so I probably should get started if i want to keep poa annua under control.

black medic is a very big problem in my subdivison with poa annua close behind... Black medic have overtaken the entire neighbor park which is right across the street from my house and the south winds really blow from the park toward my house. That means black medic seeds coming to my lawn. Oh boy...

You guys aren't listening. Pre-m right now (spring) has nothing to do with controlling Poa annua. It is not germinating in spring. It is growing and flowering (seed production). Killing it now isn't going to help you either. Subywu, you cannot renovate those areas in fall and expect to have the upper hand. It is fall when Poa germinates. And yes, just like crabgrass, it will continue to germinate as long soil temps permit. Some people think crabgrass germinates when the forsythias bloom, which is March normally. But it continues to bloom through June. Then they wonder why they still have crabgrass in summer. Poa will not stop germinating either, and all the mechanical practices don't help, such as core aerating and power raking. They bring Poa seeds to the surface, exposing them to air and light. But, you want to be able to those things in the fall. That's another reason I said Poa control and renovation coincide. The favorable time to renovate your lawn is also the best time to battle Poa annua. In my last response in this thread, I let him know that after the grass seeds germinate and the lawn is established, he still has to kill any Poa that had a chance to grow. That effort is in late fall and could well mean December.

Again.....
Do not think pre-m will help you with Poa right now. It will only help you with crabgrass and other grassy weeds, but not Poa.

Do not think you can pre-m in fall and that's all. It germinates throughout the fall growing season and as long as soil temps permit. When you're applying the last fertilizer for the season, you are also feeding Poa annua. Early season pre-m is not enough.

Do not think the pre-m you used is effective. Find out just how effective it is. It will do you absolutely no good if it only prevents germination by 50 percent because come spring, Poa doesn't care. You still have to find a way to kill off new Poa later in the fall. This may be done with pre-m products like Halts or Dimension that also have some early post-m effectiveness. But again, you want to find out which one is most effective on Poa.

Do not think battling Poa and renovating the lawn will be easy. It is not, and is often not effective because you are going to encourage Poa to germinate. You have to decide to do one and put off doing the other. If you do both, you still have to aggressively attack Poa later in the fall season without damaging your new grass.

Here are many herbicide labels and their facts sheets.

Is there an herbicide thats commonly available that I could use to kill off poa that is growing in my lawn? I have tons of it this year. I recognize that additional treatments will be required in the fall.

The only herbicides that will kill Poa without harming your grass are not commonly available and are extremely expensive.

Bestlawn, while most of the poa seeds germinate in the fall, they will germinate in the spring as well. Poa seedheads that I hand picked in the spring and throw into the adjacent flowerbeds (lazy) will germinate soon afterward. I've also thrown poa seedheads onto a pile in the driveway (lazy again) and noticed the seeds start sprouting just from spring rains. And it is not a given that the stuff will die out in the summer either. I hear what you are saying about fall coverage though and I think I may need to add an extra late fall application of pre-em to control late fall/early winter poa.

Here is my problem. I have large patches of poa out back that needs to be rounded up, or even if it dies this summer, will need to be reseeded. How do I reseed the patches without poa seed also taking over? Pre-em on fallow ground is not very effective. Luckily, I think the patches are manageable so I should be able to dig out an inch of soil and fill it back in with Scott's LawnSoil or other come seeding time. I may even apply pre-em early before this so all surrounding areas will still be covered.

The major downside of these new elite KBG (or any very dark green grass) is that any poa annua or poa trivialis infestations make the lawn look so much worse than if the lawn were lighter green!!! My neighbors have the same poa I do but you can't see it unless you specifically look for it!

which is???

Here's a link that indicates that poa annua will germinate in the spring.

Here is a link that might be useful: Poa Control