About a month ago I did what ill call a half lawn renovation, I did not have to kill the whole lawn and start from scratch. I had a very large patch of crabgrass and a lot of what I believe was nimblewill. I killed the un desired weeds and grass using an ortho product then dethatched the whole lawn to remove any dead grasses and weeds and to expose more soil. Then I put down Scott's sun and shade mix grass seed at approximately 10 lbs per 1,000 rate. I also used Scott's starter fert with weed prevention and a half dose of milorganite. I have had amazing results and have already had to mow the new grass at 4". The problem I have is that I am starting too see what I believe is poa annua and I'm unsure what to do about it. Should I just let it go this year till I start my pre emergant program in the spring or should I take a more proactive approach and try to stay ahead of the problem?
Poa annua in new grass
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Redbone46, welcome to the site.
Scott product does contain annual ryegrass. It will noticable next year to a trained eye. It could also be poa annua or the nimblewill. If you post a picture of the grass and auricles, we might be able to guess.
Disclaimer, grass is is hard and most of us get it wrong, so take our identification as a guess.
Scott product does contain annual ryegrass. It will noticable next year to a trained eye. It could also be poa annua or the nimblewill. If you post a picture of the grass and auricles, we might be able to guess.
Disclaimer, grass is is hard and most of us get it wrong, so take our identification as a guess.
That's does look like poa annua. The warm weather is making it go to seed. The other sign is the wrinkles in the leaf (left side of the second image).
So what to do about it? If not doing a reno/overseed, i would have recommended weekly apps Tenacity foliar at the 2oz rate and a PreM now. The PreM now will prevent those seeds from growing more poa annua. I would then continue more preM next year to continue a reduction in the amount that does make it thru. But you live in NY and NY does have restrictions around homeowner applications of PreM. I'm not familiar with what you could get or get someone to apply for you.
Since you have a reno, the weekly 2oz tenacity would be too much for a young lawn and the preM would also need the lawn to be more mature. You could do an application of tenacity after 4 weeks from germination, (except for fine fescues) to try to control what is growing now. Next year do plan for preM in August(therefore no Reno) to really get a handle on the poa annua.
So what to do about it? If not doing a reno/overseed, i would have recommended weekly apps Tenacity foliar at the 2oz rate and a PreM now. The PreM now will prevent those seeds from growing more poa annua. I would then continue more preM next year to continue a reduction in the amount that does make it thru. But you live in NY and NY does have restrictions around homeowner applications of PreM. I'm not familiar with what you could get or get someone to apply for you.
Since you have a reno, the weekly 2oz tenacity would be too much for a young lawn and the preM would also need the lawn to be more mature. You could do an application of tenacity after 4 weeks from germination, (except for fine fescues) to try to control what is growing now. Next year do plan for preM in August(therefore no Reno) to really get a handle on the poa annua.
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Redbone46, it sounds like the area in question is only about 1000 square feet. If you can identify any poa annua by the seedheads, I'd suggest hand-pulling any you can identify. If the soil is moist, the poa annua will pull out very easily, as it is shallow-rooted. If nothing else, you'll keep those specific plants from producing seeds this fall, and eliminate their competition with the desirable grasses.
Thank you everyone for the advice. Now that I know what it is I have a good idea on what I have to do. In a couple weeks when the grass matures I'm going to do a tenacity treatment followed by a preM plan next year. Whats everyone's advice for good preM for crabgrass, nimblewill and broadleaf weeds?
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Different folks have different preferred products and strategies. Personally, I use prodiamine as a pre-emergent, as it is reasonably inexpensive on a per-application basis. (Although the initial purchase of a 5-pound jug of water-dispersible granules is pricey, it lasts a long, long time!) I use Prodiamine 65 WDG.Redbone46 said:
I apply 3 times a year at the 3-month rate each time. This keeps me under the recommended maximum annual application amount and gives just about year-round coverage for the weeds I'm targeting.
I make the first 3-month rate application in the spring at the time of Forsythia bloom. This is typically the last week of April or early May for me. It will be earlier for folks further south. This application is to protect against crabgrass and other early summer weeds.
I make a second 3-month rate application at the beginning of August to protect against poa annua in early fall. I then make a second 3-month rate application around October 1st to provide additional protection against poa annua in late fall.
There are many other reasonable approaches, depending upon one's goals and primary weed threats in your area for your lawn.
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