My 2016 Poa Plan

[dave42]

Last year winter lasted until late-April. Then we had an unusually warm May and triv sprouted everythere! I applied multiple applications of Tenacity in May. This made the Triv angry, but it came roaring back when I fed the lawn plenty of Milorganite during our very wet June and totally filled in the yard by the 4th of July. To everybody but me, the lawn looked fabulous. Then it all faded away in July.

I did apply Certainty twice to the back yard and part of the front yard, but it wasn't until mid-August, when it was already dormant. I didn't overseed until mid-September, but the grass appears to be coming in OK. I used a northern mix that includes Award, Bewitched and Rhapsody KBG. I have 10-pound bags of each KBG seed on hand if I need to overseed and water all summer.

Here are pictures of the lawn taken on May 1st this year. Believe it or not, the yard was much worse last May:

Picture 1: Back Yard (lots of Poa A in the foreground). I applied 2 rounds of Certainty last year and overseeded in late September.


Picture 2: Front Yard. I Applied Certainty to the right side of this sidewalk last year and overseeded in late September. See how the rhododendron on the right side has almost no flowers on it? Could Tenacity and Certainty in the lawn do that?


Picture 3: Front Yard. I used Certainty to eliminate triv and tall fescue from the corner, only to have the sidewalk snowplow drive right over it. I know, first-world problems.


Picture 4: Utility island. Until last fall there were 4 bushes that formed a giant hedge that hid the transformer. The electric company cut them all down. Now I have a large annua infestation in the area. However, this entire area under the tree was probably 50% triv last year.


Here is what I have done so far this year:

April 16: Sprayed entire lawn with Tenacity at 4oz/acre and 1% DMSO. It affected the Poa Annua so fast it scared me. Seedheads out in 2 days!

April 23: Sprayed entire lawn with Tenacity at 2oz/acre and 1% DMSO.

April 30: Sprayed entire back yard and Poa Annua patches in the front with Tenacity at 2oz/acre and 1% DMSO.

May 7: I plan to do the same thing I did on April 30. But I'm concerned that if I hit the Triv too hard with Tenacity it might go dormant before I can hit it with Certainty.


My plan is to spray the entire lawn with Certainty on May 21 and June 11, following each spray with Iron Max AC 6% 15-0-0 at 9oz/1000 sq. ft.

I also have a lot of little patches orchardgrass in the back. Tenacity with DMSO makes it look sick but doesn't take it out. I might try Tenacity with triclopr this fall. Has anyone tried that combo?

Any suggestions? Before anyone mentions Renovation, it's not going to happen. When I'm not abusing it with Tenacity and Certainty, my lawn looks is the best looking in the neighborhood.
--Dave

[tlinden]

Is your seed sod quality? Double check the tag.. If it is then just continue the battle. Most here have similar struggles with poa.

If the patches are visible from tenacity then you might want to use glysophate. It will leave a bare spot whether it's killed by glysophate or tenacity so get it killed.

Also make sure you are using prem in the fall. Unfortunately it seems this is a battle over years not months.

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[andy10917]

Even though the label for Certainty on Cool Season grasses is old (2008), I'd swear it has changed. It now says that applications should be between June 1 and September 15. I never remember seeing that before, but it lines up with my experience - after the Spring flush and before Triv retreats from the heat. In NY, that seems to leave a window called "June". And Yes, it's a multi-year battle - my front-yard battle was 6-7 years, and my Backyard battle is in its third year (no win there yet).

[dave42]

Tlinden, Only the Bewitched is sod quality. I bought the seed at the end of the season with the intention of dormant seeding after Thanksgiving, and that's all Preferred Seed had in stock. I didn't end up dormant seeding due to an injury and the fact that it never really got cold until January. Should I discard the Rhaosody and Award?

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[dave42]

Andy, I've read about your multi-year battle and it gives me hope. The Certainty appears to have thinned out the PR and fescue a bit in the back yard too, so I'm hopeful that I can increase the percentage of KBG in the lawn to help crowd out the triv.

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[dave42]

Once the triv is brown, I assume I should rake up the dead grass and stolens. Or is that likely to help it spread?

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[tlinden]

Well the problem with the non sod quality seed is you don't know how much of it has the weed seed in it. So you could be re-creating the problem if you seed with it again. I'll leave the decision up to you.

[dave42]

Two quick questions:

1) My KBG is suddenly seeding like crazy. Is this a bad time to hit it with Certainty?

2) Section 9.0 of the old Certainty label says it can be applied to KBG/PR/FF mixtures. Section 9.1 says to apply at .25 oz/acre to control triv in creeping bent. Section 9.2 says to apply at .5 oz/acre to control triv in pure KBG. Nowhere does it discuss KBG mixtures. Has anyone (other than Purdue) tried multiple applications at .25 oz/acre?

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[TimmyG]

I don't have answers, but if it makes you feel any better that you have company, know that I'm in the same boat and will be proceeding as you are. I have a KBG/PR/FF NoMix (with random TF clumps), the KBG is in full seed, and I will be applying Certainly real soon for the first time to target triv. I've read all the same things as you and have had to extrapolate my own plan.

Subject to change, my plan is to spot spray (more like large patch spray) at the 0.25 oz/acre rate at roughly 14-day intervals, for a total of three applications. I don't want to be too aggressive given my NoMix species, at least not until I have more experience with this product under my belt. I expect to have to do this again next year, at which time I'll go more aggressive as needed based on my experience this year. I'll be happy with some suppression for now.

[dave42]

This is the study from Purdue regarding the addition of Iron and Nitrogen to Velocity and Certainty:

https://turf.purdue.edu/report/2008/PDF/508.pdf

It says 3 14-day applications of Certainty at 0.25 oz/A (with Fe and N) reduced PR cover to 70% compared to 47% at 0.50 oz/A and 85% for the check plot.

The effect on Triv is harder to determine because even the check plot was going dormant by the middle of the study. Applications were made on 6/11, 6/24, and 7/8. On July 8, the 0.25 oz/A plot had 19% PT cover compared to 7% cover for the 0.50 oz/A and 53% for the check plot. So even at the lower rate there is quite a reduction, and since Andy says PT is a "weak perennial" the PT should eventually go away.

My goal is to gradually eliminate the Triv and gradually reduce the amount of PR and FF in the lawn while filling in those holes with KBG. Maybe a few years of this light application is the answer.

So I'm planning to do a full 0.50 application on the back yard, which got two applications last August and September. I'm going to try the 0.25 rate on the front yard, to see how bad the CCS is at the lower rate. I'm adding Fe and N to both areas, probably in a separate spray so I can spray Certainty right up the to sidewalks without staining them with iron.

[bernstem]

There is nothing on the label to give rates for mix lawns as Certainty will kill the Rye and fescue in the mix.

[dave42]

Actually, section 9.0 of the 2008 label said "This product is recommended for use on creeping bentgrass, Kentucky buegrass and Kentucky bluegrass mixtures with perennial ryegrass and/or fine fescues".

[bernstem]

I stand corrected then. Even so, it will kill some of the PR and FF and TTTF.

[dave42]

Yep. And I'm fine with that, as long as I don't end up with huge bare spots. I need to apply Pre-Em this fall to stay ahead of the Poa Annua so I won't be overseeding this fall.

[dave42]

I got all of the Certainty sprayed yesterday. .25 oz/A in the front and .5oz/A in back. Even with a backpack sprayer, 15 gallons is a lot of work.

Now it looks like it's going to rain all weekend. Is there any point is spraying the IronMax in the rain?

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[dave42]

I ended up spraying the iron and nitrogen in the drizzling rain. I figured that was better than delaying it too much.

I haven't done anything to feed the lawn yet this spring. Should I spread Milorganite between Certainty/Iron/Nitrogen treatments or wait until after the last Certainty treatment? I want to encourage the KBG to spread and fill-in the bare spots that will soon be emerging, but don't necessarily want to do the Triv any favors.

Any opinions out there?

[dave42]

September Update:

Well it turns out either this plan doesn't work or I chose the wrong year to try it. Before my third Certainty application the Triv was already dormant. The patches remained brown all summer. A couple of weeks ago I mowed short, raked up the dead grass and stolens, spread KBG seed and top dressed. With twice-daily watering I have KBG germinating, but also Triv in the same areas as before.

Triv is harder to spot in a Northern Mix lawn, because the color isn't is obvious and it looks a lot like fine fescue when it starts. But pull it out and the stolens with tiny bundles of roots are there.

So my decision now is whether I should let the KBG mature so it can handle a round of full strength Certainty in May, or hit it now and have a thin lawn all winter.

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[seiyafan]

The best time to take out triv is in late spring.

[kbgfarmer]

One question. Asking because I want to attempt it but not necessarily kill my whole lawn. How did your no mix lawn look like after a .5 oz/acre blanket spray? Bare and thin everywhere or just some minor stunting that went away? If so how long did it look sick for. I asked a similar question in your soil test post but found this old post using the search field. Thanks for your thoughts and help in advance.

[kbgfarmer]

Few questions. I want to attempt a .5 oz/acre blanket app of certainty to combat trivialis and quack. Hesitant to do so because of the potential for killing the whole lawn. I saw you did it on a nomix lawn similar to mine. I think I have my sprayer calibrated pretty well and technique down to decrease any double spraying and overlap. How did your lawn look after? Thin and sickly looking or full of bare spots? If stunted and sickly looking how long did it last? I asked a similar question in your soil test post but later found this old thread. Thanks in advance for your help.