Fall overseed 2018:

 

Spring 2019 after tenacity:

 

Spring 2019 2-3 weeks post tenacity:

 

I know this problem well, I lost 2 years wondering why I always dead spots in the summer, and why some grass was lighter than others. It was POA Annua the whole time.

First you have to figure out if it's POA Annua or POA Triv. Count your self lucky if the light spots have seed heads. That means it's POA Annua, Triv is impossible, Annua is a nuisance. Triv doesn't have seed heads like annua.

You have to realize there are millions of POA Annua seeds in the lawn. They last for years. Every year in late August to November they germinate if you don't put down a pre-m. Unfortunate that is when people also over-seed.

The only way I found to break the cycle was to reno with KBG that spreads on its own and very tolerant to high doses of Tenacity. I can kill large patches of POA and the KBG just fills in. That way I can always get the pre-m down. Yearly over-seeding is just as good for POA annua as it is for the grass your trying to fill in.

You don't have that luxury, maybe you can kill it with tenacity apps, then replace the areas with sod. Some people do that when they battle Triv that can only be killed in the spring.

Plan on battling POA Annua every year, even with a pre_m, but on my 1st spring after a pre-m I have a lot less. I should have smaller more isolated pockets every year, but there will always be some, and the tenacity will be a yearly spring practice.

Last bit of advice, don't assume the POA annua is dead even if it's all shriveled up, you would be surprised the spots that came back mid June on me once I reached the tenacity limit. Pull large clumps even if it seems dead, pull it out just in case. The sections I hand pulled never came back, the sections I thought would rot away, came back.

Good luck!

 

bkel101, can you give us some close up's of the lighter green grass? The light green in the fall overseed pictures is not poa A and I'm curious what it is. Not saying you have poa T but based on these pic's, the thought occurs to me, particularly the dead spots in July pics and I can see a couple huge oaks/maples? Does your front door face East? For this pics, would be good to get closeup of the leaf blade and the ligule. See the vid below for how to ID the ligule. Will try to help if I can.

https://www.youtube.com/watch?v=6JiqIbIM7OQ

 

bkel101, one more question. Did you examine the dead spots in July? Do they look like this

https://www.youtube.com/watch?v=bgKcG0ivCmQ

 

bkel101, can you give us some close up's of the lighter green grass? The light green in the fall overseed pictures is not poa A and I'm curious what it is. Not saying you have poa T but based on these pic's, the thought occurs to me, particularly the dead spots in July pics and I can see a couple huge oaks/maples? Does your front door face East? For this pics, would be good to get closeup of the leaf blade and the ligule. See the vid below for how to ID the ligule. Will try to help if I can.

This is great, I'll try and get pics and close ups posted this afternoon

 

I know this problem well, I lost 2 years wondering why I always dead spots in the summer, and why some grass was lighter than others. It was POA Annua the whole time.

First you have to figure out if it's POA Annua or POA Triv. Count your self lucky if the light spots have seed heads. That means it's POA Annua, Triv is impossible, Annua is a nuisance. Triv doesn't have seed heads like annua.

You have to realize there are millions of POA Annua seeds in the lawn. They last for years. Every year in late August to November they germinate if you don't put down a pre-m. Unfortunate that is when people also over-seed.

The only way I found to break the cycle was to reno with KBG that spreads on its own and very tolerant to high doses of Tenacity. I can kill large patches of POA and the KBG just fills in. That way I can always get the pre-m down. Yearly over-seeding is just as good for POA annua as it is for the grass your trying to fill in.

You don't have that luxury, maybe you can kill it with tenacity apps, then replace the areas with sod. Some people do that when they battle Triv that can only be killed in the spring.

Plan on battling POA Annua every year, even with a pre_m, but on my 1st spring after a pre-m I have a lot less. I should have smaller more isolated pockets every year, but there will always be some, and the tenacity will be a yearly spring practice.

Last bit of advice, don't assume the POA annua is dead even if it's all shriveled up, you would be surprised the spots that came back mid June on me once I reached the tenacity limit. Pull large clumps even if it seems dead, pull it out just in case. The sections I hand pulled never came back, the sections I thought would rot away, came back.

Good luck!

So basically overseed in fall and tenacity in spring? And just live with the battle?

I def have lots of seed heads

 

So basically overseed in fall and tenacity in spring? And just live with the battle?
I def have lots of seed heads

KBG is the secret weapon because....

1.) It spreads on its own so you can use a pre-m in the fall
2.) It is very resistant to tenacity, not sure how TTTF is
3.) You can allow the lawn to go dormant in the summer w/o dyeing, which kills the POA

In your case...

Check the Tencity labels for your lawn, but definitely at least come up with a tenacity schedule and kill what you can in the spring. I try to do a few tenacity apps, hurt the plants, then hand pull when I can because the roots are now weakened..

Come early August try to reseed, keeping in mind your trying to get your seed up before the nights get cooler and the POA germinates. Key to that would be use tenacity as a pre-m when over seeding. I have seem some do more tenacity sprayed at the 30 day mark, but that's with KBG, not sure how it is with TTTF.

Your goal is to get the TTTF to the point where you can get dimension down. Check the label but Dimension can be used 30 days after germination. If you got any new TTTF you were trying to grow and a few cuts in by Sept 1st, you can hit it with a Dimension app.

You may not prevent all the POA annua seeds with your Dimension app, and tenacity is not a fool proof way of preventing POA annua from germinating while seed, but that seems like one way to time it all to minimize POA Annua.

Some on here may disagree, but in my POA Annua infested yard, tenacity didn't do a great job as a pre-m when I was doing my KBG reno. But then again I watered too much also.

You will be back fighting it again in the spring, but you win the in increments, there isn't one magic herbicide that kills it all in one shot. A lot of peoples lawn problems would be solved if they were.

 

So basically overseed in fall and tenacity in spring? And just live with the battle?
I def have lots of seed heads

KBG is the secret weapon because....

1.) It spreads on its own so you can use a pre-m in the fall
2.) It is very resistant to tenacity, not sure how TTTF is
3.) You can allow the lawn to go dormant in the summer w/o dyeing, which kills the POA

In your case...

Check the Tencity labels for your lawn, but definitely at least come up with a tenacity schedule and kill what you can in the spring. I try to do a few tenacity apps, hurt the plants, then hand pull when I can because the roots are now weakened..

Come early August try to reseed, keeping in mind your trying to get your seed up before the nights get cooler and the POA germinates. Key to that would be use tenacity as a pre-m when over seeding. I have seem some do more tenacity sprayed at the 30 day mark, but that's with KBG, not sure how it is with TTTF.

Your goal is to get the TTTF to the point where you can get dimension down. Check the label but Dimension can be used 30 days after germination. If you got any new TTTF you were trying to grow and a few cuts in by Sept 1st, you can hit it with a Dimension app.

You may not prevent all the POA annua seeds with your Dimension app, and tenacity is not a fool proof way of preventing POA annua from germinating while seed, but that seems like one way to time it all to minimize POA Annua.

Some on here may disagree, but in my POA Annua infested yard, tenacity didn't do a great job as a pre-m when I was doing my KBG reno. But then again I watered too much also.

You will be back fighting it again in the spring, but you win the in increments, there isn't one magic herbicide that kills it all in one shot. A lot of peoples lawn problems would be solved if they were.

Just to make sure I get it....rather than wait till late summer / early fall , overseed in the heat of early August in order to get the new grass ready for dimension right?

 

Yes, early so you can get a dimension app down to take care of the POA Annua before it starts to germinate.

You won't beat it, but you can limit it, if you hold the TTTf germination to about 3 weeks. But I'm not that familiar with it, I'd work backwards from Sept 1st.

Assume your going to drop Dimension on Sept 1st, then read the dimension label on how long after germination you can apply dimension, then plan on the worse case of how long it takes TTTF to germinate. That will give you a date you need to start.

Obviously some kind of automatic watering is essential when seeding in August, plus enough water to keep it alive post germination. Its not an easy trick in August a lot can go wrong.

 

Not saying this is a cheap solution, but it is what I am considering doing this summer/fall.
-Apply low rate Tenacity in late summer/early fall as temps start to approach Poa Annua germination timing.
-7-10 days later, overseed lawn and apply another low rate of Tenacity.
-7-10 days later, apply third low dose of tenacity. Make sure you aren't going above yearly limit.
-In theory, once roots are established, prodiamine/dimension could be used to prevent any further germination of Poa. I think I am skipping this step because I don't want to risk killing all my new/young seedlings. I may do a good month and a half after overseeding with fescue.
-Once TTTF is strong, apply 1 oz/gallon/1k of 42% Ethofumesate (Poa Constrictor, RightLine ETHO 4 SC, etc.).
-If timing permits and you feel it is required. Repeat another 1 oz/gallon/1k of 42% Ethofumesate.

The Tenacity should prevent the Poa Annua from emerging while still allowing you to overseed/patch your fescue grass. The ethofumesate will kill any small amount of Poa that you may miss with the Tenacity. Hopefully the following spring, there will be both strong new fescue and no Poa. Following years should just be a pre-m routine in the late summer/early fall to prevent.

EDIT: Another tool possibly worth considering is to pre-soaking/pre-germinate your seed by keeping it in a bucket of water before throwing out the seed. TTTF only takes about a day in a bucket of water I have heard. The advantage being that you are shortening the window for your seed to germinate and therefore reducing the Tenacity that you have to apply. Also would be reaching the point where it is safe to apply Prodiamine and Ethofumesate quicker.

 

I have the lime green devil in my lawn too. I'm in Canada where it's a pita to get pre m and tenacity. My plan is to buy a ProPlugger, roundup the Poa and transplant some established grass into the spots I killed off.

As you don't have kbg you could consider this approach: apply pre m in the areas you had issues and pull some plugs from a place far away from the poa (backyard for example?) and then don't pre m that area and reseed there.

No idea if anyone's tried this approach before but worth pondering over.

 

bkel101, can you give us some close up's of the lighter green grass? The light green in the fall overseed pictures is not poa A and I'm curious what it is. Not saying you have poa T but based on these pic's, the thought occurs to me, particularly the dead spots in July pics and I can see a couple huge oaks/maples? Does your front door face East? For this pics, would be good to get closeup of the leaf blade and the ligule. See the vid below for how to ID the ligule. Will try to help if I can.

Thanks for the video.

Here is some of the light green spots. (I'll get the other info for you too).

 

Bkell101, looking at the first pic, that is a poa species which means it's very likely either poa annua, poa triv or poa pratensis (aka., kentucky blue grass). I've never seen a clump of annua look like that, particularly with no seed heads so I rule that out. I don't see any obvious ligule to rule out KBG but on the last pic, I THINK I can make it out. If there is a ligule then it's very likely Triv. If you watch that video I did showing the ligule, can you pull a few blades and see if you see that pointed, white-ish thing called the ligule? If you do NOT see it then it's likely KBG. Also, I don't see any obvious rhizomes in pic 1 but that is such a small piece that it doesn't make for a positive ID. However, everything else you've shown makes me think you've got a decent amount of triv in that yard. I don't doubt you also have annua and are seeing those seedheads but am saying you can easily have both. I'm asking about the front door because if those large oaks are blocking the southern sky then that furthers the case for triv. I don't need to know if they are oaks or maples, etc. Just curious what part of the sky they are blocking.

 

I've never seen KBG "string" that much when cut...

 

With Poa annua and tttf, I would seed late summer/ really early fall. Both mesotrione and ethofumesate can be sprayed at seed down. Repeat a second meso app and a second etho app. Then switch to a Prodiamine app. This will cover all winter and Poa annua won't be there in the spring. Repeat annually for a few years. This is only for tttf, not kbg or rye.

 

With Poa annua and tttf, I would seed late summer/ really early fall. Both mesotrione and ethofumesate can be sprayed at seed down. Repeat a second meso app and a second etho app. Then switch to a Prodiamine app. This will cover all winter and Poa annua won't be there in the spring. Repeat annually for a few years. This is only for tttf, not kbg or rye.

This is great. What would your regiment be if you
Have KBG and rye?

 

With Poa annua and tttf, I would seed late summer/ really early fall. Both mesotrione and ethofumesate can be sprayed at seed down. Repeat a second meso app and a second etho app. Then switch to a Prodiamine app. This will cover all winter and Poa annua won't be there in the spring. Repeat annually for a few years. This is only for tttf, not kbg or rye.

This is great. What would your regiment be if you
Have KBG and rye?

KBG would have some issues with this method. You need to wait 6 weeks after application to apply seed. Then you need to wait 8 after germination to reapply ethofumesate. Could use it the following year on established kbg though. Then let the kbg creep to fill gaps instead of overseeding.

Meanwhile with TTTF, ethofumesate can be put down at seed and reapplied 2-3 weeks after germinating.

 

@tgreen You mentioned a clump that big without seed heads, curious if you see Poa T with seed heads or is it a Poa A/KBG thing?

 

bkel101, one more question. Did you examine the dead spots in July? Do they look like this

Thanks for the great video @to green! Unfortunately it made me realize I have a few areas with extensive Triv in my backyard where every summer it does and pulls up like that in droves...always figured it was grub damage. Guess I have my work cut out for me...but it gives me even more reason to get moving on a KBG Reno I've been thinking about 🤔

 

Sorry to hear about the Triv, killing it is impossible.

You can kill it with round up, but it often still comes back, its a multi year process. You can try and kill it slow with multiple round up apps in the spring before it goes dormant, once it yellows for summer, you have to wait another year.

Even if you kill it with RU and remove the soil, it often comes back. If going the RU route, make sure you spray an area of about 1' past it. No matter what you do; sod or re-seeding will have to be done, but with Triv don't just assume it will be gone because you reno the lawn.

 

With Poa annua and tttf, I would seed late summer/ really early fall. Both mesotrione and ethofumesate can be sprayed at seed down. Repeat a second meso app and a second etho app. Then switch to a Prodiamine app. This will cover all winter and Poa annua won't be there in the spring. Repeat annually for a few years. This is only for tttf, not kbg or rye.

This is great. What would your regiment be if you
Have KBG and rye?

KBG would have some issues with this method. You need to wait 6 weeks after application to apply seed. Then you need to wait 8 after germination to reapply ethofumesate. Could use it the following year on established kbg though. Then let the kbg creep to fill gaps instead of overseeding.

Meanwhile with TTTF, ethofumesate can be put down at seed and reapplied 2-3 weeks after germinating.

Agreed. Kbg, I would do a reno and seed with meso. That's it. Poa annua will be there the first fall and spring but should die out in the summer heat. Apply Prodiamine late summer before poa annua germinates. Rely on kbg's spreading power to fill gaps and thicken. Use a proplugger for bigger gaps. Annual use of Prodiamine or some prem before poa annua germinates takes care of it.

Rye, seed and spray meso. In 2 weeks, you'll have a nice lawn. Rye establishes fast. In a month, if you have empty spots, repeat with seed and meso. Switch to Prodiamine later. Rye is easy...

I would only bother with etho for tttf. But, boy does it work! I did a reno and I'm poa free!

 

Thanks for the advice guys - sounds like a good plan moving forward. You make it sound almost manageable 😂

 

@tgreen You mentioned a clump that big without seed heads, curious if you see Poa T with seed heads or is it a Poa A/KBG thing?

Poa T does go to seed but a few major differences from annua. 1) Annua goes to seed at incredibly short heights (under 1 inch) vs Poa T. 2) Poa T is a spike seedhead like KBG whereas annua is an open, panicle shape. The look is totally different 3) Seed timing is different. Poa A practically goes to seed as soon as it emerges. I can have snow on the ground and see small Poa A seed heads. Triv seed timing is more like KBG where you get a flush later in Spring than Poa A. Here's another vid I did where you can see Poa A very short already seeding vs Poa T at 4 inches and no where close to seeding.