# Follow-up Pre-m (tenacity / dimension) after overseeding



## Dan1234 (Aug 31, 2018)

Hi All,

On 8/10 I overseeded with PRG to get a quick establishment and fill in of bare spots. Would expect germination in another day or two (hopefully!)

I applied this with Scotts Starter with weed preventer. I do have liquid tenacity, but felt more comfortable with a granular approach.

I understand this will give me several weeks of pre-m coverage.

I've never done any pre-m coverage in late summer / early fall, so I'm glad to get coverage this time of year.

My question is, when can I and should I apply more pre-m to this overseeded lawn to keep the coverage through the fall?

I have plenty of dimension in the garage and could also get more scotts starter with weed preventer if that works too.

appreciate the input!


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## Virginiagal (Apr 24, 2017)

Here is some information from Purdue on herbicide delays after seeding:
https://www.agry.purdue.edu/turfnew/tips/2008/04_10delays.html


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## Dan1234 (Aug 31, 2018)

Thanks, that is a great article!

I think a follow up app of the Scott's starter w/ tenacity seems to be my best bet.

Thinking it should be safe with PRG by sept 7/8 and good timing for whole lawn to get a shot of nitrogen.

Dan


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## Virginiagal (Apr 24, 2017)

Read your bag too about subsequent applications. My bottle of Tenacity says to wait until after two mowings or four weeks after emergence. Keep in mind that it will provide only about a month of protection. Also keep in mind that you are limited in how much Tenacity you can use in a year (16 oz/acre). What are you trying to protect against? Poa annual or just ordinary winter weeds like chickweed? Maybe it might make sense to use it if you want want to use Dimension but want to hold off on it for another month.


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## Dan1234 (Aug 31, 2018)

Will do.

Would want to avoid poa annua, chickweed and other grassy weeds I saw early spring.

I feel like dimension in October would be late, but not sure when these various things germinate


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## tgreen (Oct 20, 2018)

Dan1234 said:


> My question is, when can I and should I apply more pre-m to this overseeded lawn to keep the coverage through the fall?
> 
> I have plenty of dimension in the garage and could also get more scotts starter with weed preventer if that works too.
> 
> appreciate the input!


You can run the dithiopyr/ dimension now. There are labels that allow dimension 2 weeks after first emergence. I would go even sooner. See video below.


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## rtdad (Jul 13, 2019)

Dan1234 said:


> Hi All,
> 
> On 8/10 I overseeded with PRG to get a quick establishment and fill in of bare spots. Would expect germination in another day or two (hopefully!)


On a related note, in general should we expect germination that quickly? 4-5 days?
And how often are you watering during that time?

I ask because I overseeded recently and I'm not expecting much for a week or two. Thanks


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## Dan1234 (Aug 31, 2018)

@rtdad - what did you overseed with (TTTF, KBG, PRG)? i went with perenniel rye grass, which should have a fairly quick germination. I'm hoping to see initial germination tomorrow (day 4) and widespread easily by the weekend. My sprinkler timer is set for 4 times a day, but have gotten light rain past two days so mother nature is helping.

@tgreen - will have to get some time to watch that video. Seems interesting. I always thought dimension or prodiamine would negate grass seeding, but will have to watch for the timing and methods, thanks!


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## rtdad (Jul 13, 2019)

@Dan1234 Scotts sun & shade which has a mix of ryegrass, fescue and blue grass..


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## Dan1234 (Aug 31, 2018)

@rtdad - ah, you should see a variety of germination times starting with the rye, then fescue and then the kbg.

how many days since seed down are you?


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## rtdad (Jul 13, 2019)

Dan1234 said:


> @rtdad - ah, you should see a variety of germination times starting with the rye, then fescue and then the kbg.
> 
> how many days since seed down are you?


Going into day 4.. lots of watering


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## Dan1234 (Aug 31, 2018)

I would bet the ryegrass in that mix should pop today/tomorrow for sure.

I put some in a pot when I overseeded and had a ton of germination yesterday (day 3) and today I checked the yard and saw some initial germination (day 4)


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## wingnut (May 6, 2020)

Bringing this thread back to life rather than starting a new one.

Very similar situation to OP. I'm in Atlanta, aerated and restored/overseeded a lawn on September 17th that had been decimated by Poa Annua in the spring. After the disappointing spring of poa (tenacity did not work as well as hoped), I kind of let it go in the summer to crabgrass knowing I'd have to wipe out large swaths of it.

So, I nuked it in early sept and seeded fescue earlier (Sept 17) rather than my usual October. My goal is to get the fescue up and then hit it with a tougher pre-emergent than tenacity (Dimension?). Atlanta is running in the mid-80s now with nights in the mid 60s, now a full week and a half after seeding. Fescue popped early - saw sprouting in 5 days. Lots of rain and heat are working to help it sprout. I'm doubtful that poa is yet active underground, but I know it will come soon, probably when daytime highs hit the lower 70s. I have yet to mow, but probably can do so this weekend.

So, when would you all put down dimension? Tgreen posted a video above saying the original poster could put it down early, but that video seems de-activated.

Racing against time here to beat the poa annual - my lawn killer extraordinaire.


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