# Fall Preemergent App



## bptexan (Jun 21, 2020)

According to Neil Sperry, today (9/1) is the first day of the preemergent window for North TX 9/1-9/15 is recommended. But, I've also seen advice stating that the fall preemergent should be applied once soil temps approach 70 degrees and falling.

Lastly year, I applied prodiamine around labor day, and I still had many poa popups. I wonder though if it had something to do with the abnormally warm December. I checked greencast and we did have soil temps bounce up into the upper 60's several times in December.

Looking at the 5/10 year averages, DFW doesn't get to 70 degree soil temp until mid-Oct. I know early is better than late, but what's the right plan of attack?

Thanks!


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## p1muserfan (Jul 7, 2019)

I follow Greencast, on average I end up applying around October 1st. My results are pretty good, but this year I'm gonna add simazine to my first split app of prodiamine and then apply prodiamine again 6-8 weeks later.


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## Bombers (Jul 14, 2020)

Agree. I'm not too far off from you guys and you need at least simazine with prodiamine for Poa. Prodiamine alone isn't cutting it even with split fall apps. Poa has developed resistance in the southwest for a while now. Ask around all the good spray companies or read up on universities published studies. They're stacking 2 or 3 pre-emergents now to fight off weed pressure.

Regarding the time frame. I had good results last year with mid September (9/12 first 1/4 rate app), and follow up with another 4-6 weeks later (10/25). Soil temp around your house is going to be a bit warmer too compare to weather app averages. There are also those rogue 2-3 days cold front where soil temp dips well below average which is just enough for some seeds to germinate. You might not see it, but it has broken out underneath the soil or below your canopy where you can't visibly see. By the time you try to time right at 70*F, a good bit of weeds will have flushed so you're not getting excellent prevention. When in doubt, apply early by 5 degrees or a week before your region's "historic" time. Especially if you don't have irrigation to push the AI into the soil.


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## Pannellde (7 mo ago)

Poa A. seeds can lay dormant for years. Both pre-emergents and post-emergent herbicides could be necessary to control it.

I use the 70°F soil temp for one week theory for pre emergent.


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## FATC1TY (Jul 12, 2017)

It's always better to be early than late, but I think right now is probably too early, but I don't know the area weather well.

In Atlanta area I've been pretty successful with 3rd or 4th week of Sept applications, as it aligns with my next 6 month application for the spring.


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## thelawnlife (9 mo ago)

Spectacle Flo 2 apps bout 35 -45 days apart 2nd app with Princep 4L (simazine) works for me. Depending on temps late Sept. early Oct for 1st app.


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## cldrunner (May 14, 2019)

@bptexan My recommendation is to get it down as soon as possible. We have rain on the forecast and that will help. I also agree that a second mode of action will help as well. Simazine is a good choice. Specticle Flo is even a better choice. Using all three works great. For example, Prodiamine now and Simazine and Specticle Flo in 30 days. Gotta make sure it gets watered in before our first cold front.


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## bptexan (Jun 21, 2020)

Thanks for the advice so far.

Specticle Flo would be great but damn it is pricey. I think I'll go with the Simazine.


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## thelawnlife (9 mo ago)

bptexan said:


> Thanks for the advice so far.
> 
> Specticle Flo would be great but damn it is pricey. I think I'll go with the Simazine.


Look in the marketplace for specticle FLO or equivalent


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## FATC1TY (Jul 12, 2017)

bptexan said:


> Thanks for the advice so far.
> 
> Specticle Flo would be great but damn it is pricey. I think I'll go with the Simazine.


It's actually not expensive when you look at cost per application and how good it is.


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## Woffski (Apr 26, 2020)

Can someone explain the difference between Dithiopyr and Prodiamine? I use Prodiamine, and have access to Dithiopyr. Is it better to use one or the other at different situations? Thanks.


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## rjw0283 (May 11, 2020)

+1 for simazine.. prodiamine alone does not cut it for me. I added simazine last fall and had 0 poa this spring. NC here I spray in late Sept or Early October... Poa hits hard in spring for me...


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## csl23 (Jul 22, 2021)

I plan on using spec flo for 1st time this year. Supposedly it's the best. Is it necessary to add an additional pre emergent along with spec flo? Traditionally I have used a split app of dimension in the fall


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## ag_fishing (Feb 3, 2021)

Prodiamine now and then split apps of simazine October 1/December 1 for me. I'll be adding in specticle flo in a year or 2 though.


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## DFW245 (Jul 23, 2021)

Applied simazine literally minutes before about an inch of rainfall today. September 15 I'm due for another round of Prodiamine. I may push it out to October 1 though. That should last me until spring time where I'll do another app of simazine in Feb and Prodiamine in March.


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## Pannellde (7 mo ago)

Woffski said:


> Can someone explain the difference between Dithiopyr and Prodiamine? I use Prodiamine, and have access to Dithiopyr. Is it better to use one or the other at different situations? Thanks.


https://www.centraltis.com/news/ask-the-expert-dithiopyr-vs-prodiamine/


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## dofdk3 (5 mo ago)

Pannellde said:


> Woffski said:
> 
> 
> > Can someone explain the difference between Dithiopyr and Prodiamine? I use Prodiamine, and have access to Dithiopyr. Is it better to use one or the other at different situations? Thanks.
> ...


Excellent article! Thanks for posting that!


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## Bombers (Jul 14, 2020)

Indaziflam (specticle or esplanade 200 sc) is better than simazine and lasts longer. I'll also relay the sentiment that you need very little. With Esplanade you only need .161 oz/1k yearly max. 1 oz of product will last your yard 3 years! With only 2k of lawn, you can buy a small split in the marketplace of either really and see how it works wonder when stacked with prodiamine.


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## Ken_K (Apr 16, 2020)

For people living in Atlanta here's a link to current soil temperatures from the Atlanta Athletic Club in NE Atl and are updated daily. They're listed at 2", 4" and 8" depths - http://www.georgiaweather.net/index.php?content=calculator&variable=CC&site=DULUTH


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## Highlife159 (May 19, 2021)

@Ken_K is the 2" the one we need to be paying more attention to?


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## Ken_K (Apr 16, 2020)

Good question and I don't know the correct answer. Maybe someone else will weigh in.



Highlife159 said:


> @Ken_K is the 2" the one we need to be paying more attention to?


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## DFWdude (Aug 28, 2020)

Is simazine avail in granular form?


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## Rick S (Feb 21, 2021)

I had a ton of weeds all season last year. I applied Prodiamine, Princep, and Esplanade in split apps last Fall. It worked very well for me.

Some people reported that Princep dings their Bermuda. I certainly saw that and I assume it was the Princep. My growth stopped instantly and I lost a lot of color. That lasted for 30 days. Then I started to see some decent color come back.

I am spraying just Prodiamine and Esplanade tomorrow. So, I will find out soon if it was definitely the Princep. I am near Richmond, VA and I apply my first split app between Sept. 1-7. As someone said before: There is nothing wrong with applying a little early. There can be a problem if you apply a little too late.


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## ag_fishing (Feb 3, 2021)

Is Specticle Flo a Fall only pre emergent? Debating on stretching it to go for 2 years on one bottle. 9oz/acre rate in the fall and 6oz/acre in the spring. Or is it better to just do those 2 apps 30-45 days apart in the fall and done for the year with maybe prodiamine in the spring?


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## Bombers (Jul 14, 2020)

It works very well on both for me, but if you have prodiamine on hand and works well for spring, it's better long-term to rotate herbicide to prevent resistance and help stretch the product and your wallet.


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## ag_fishing (Feb 3, 2021)

Bombers said:


> It works very well on both for me, but if you have prodiamine on hand and works well for spring, it's better long-term to rotate herbicide to prevent resistance and help stretch the product and your wallet.


I might move to a full rate of prodiamine in the spring and specticle in the fall then. Making specticle last 2 years helps the wallet not hurt so bad


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## Pannellde (7 mo ago)

DFWdude said:


> Is simazine avail in granular form?


Yes. https://www.pestrong.com/2066-princep-caliber-90-herbicide-simazine-25-lbs.html


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## Pannellde (7 mo ago)

Ken_K said:


> Good question and I don't know the correct answer. Maybe someone else will weigh in.
> 
> 
> 
> ...


USDA recommends 4". https://www.nrcs.usda.gov/wps/PA_NRCSConsumption/download/?cid=nrcseprd1356820&ext=pdf

This is corroborated by Greencast that reports 0-10 cm (3.9") soil temp


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## DFWdude (Aug 28, 2020)

Pannellde said:


> DFWdude said:
> 
> 
> > Is simazine avail in granular form?
> ...


Thanks. And holy sheet is that expensive.
Looks like it still has to be mixed with water and sprayed.


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## Batsonbe (May 9, 2019)

I was curious if I could use specticle on my lawn this year. Part of my lawn i seeded, therefore I will not spray specticle there due to the label restrictions. 
However my question is that over the last 3 years I have went from a salad bar of weeds to almost 90% weed free. Each year the bermuda continues to improve. 
Could I use specticle across my lawn or is that considered not "established" grass? I was looking at 4 lighter application rates 
Thank you


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## rbvar (May 28, 2020)

ag_fishing said:


> Is Specticle Flo a Fall only pre emergent? Debating on stretching it to go for 2 years on one bottle. 9oz/acre rate in the fall and 6oz/acre in the spring. Or is it better to just do those 2 apps 30-45 days apart in the fall and done for the year with maybe prodiamine in the spring?


Two apps of prodiamine March/May and two apps of Specticle Flo September/November is my plan for next year.


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## bptexan (Jun 21, 2020)

Okay, I wound up buying esplanade 200sc on the marketplace. I was about to apply but the AI rates are different between Specticle & Esplanade -- 19.05% / 7.4% respectively. I know the Esplanade is for Ag, but many have mentioned they used it on their lawns. The suggested rate from the labels are Specticle (6-10oz per acre) / Esplanade (3.5 - 7 oz per acre). 

I went low 3.5oz per Acre rate, but what are others using Esplanade doing?


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## Bombers (Jul 14, 2020)

bptexan said:


> Okay, I wound up buying esplanade 200sc on the marketplace. I was about to apply but the AI rates are different between Specticle & Esplanade -- 19.05% / 7.4% respectively. I know the Esplanade is for Ag, but many have mentioned they used it on their lawns. The suggested rate from the labels are Specticle (6-10oz per acre) / Esplanade (3.5 - 7 oz per acre).
> 
> I went low 3.5oz per Acre rate, but what are others using Esplanade doing?


I converted Esplanade's concentration and yearly max to match Specticle's which turns out to be a hair above 7 oz/A. This is lower than it's label of 10 oz/A yearly max, which is good because you can stretch the product longer. I had no issues with efficacy controlling weeds. In fact, only a handful (mostly sedges) in a year's worth of usage so far.


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## cldrunner (May 14, 2019)

bptexan said:


> Okay, I wound up buying esplanade 200sc on the marketplace. I was about to apply but the AI rates are different between Specticle & Esplanade -- 19.05% / 7.4% respectively. I know the Esplanade is for Ag, but many have mentioned they used it on their lawns. The suggested rate from the labels are Specticle (6-10oz per acre) / Esplanade (3.5 - 7 oz per acre).
> 
> I went low 3.5oz per Acre rate, but what are others using Esplanade doing?


 I agree with @Bombers . I think you will be very pleased with a 3.5 to 5 oz per acre. I am the same in that I never needed to blanket spray a post emergent app this year. I just did an occassional spot spray. I use Esplanade and you can really stretch it at those rates and it is highly effective. I am also mixing with a low rate of prodiamine and Simazine later in the Fall and early Spring and apply a 1/4 rate four times a year.


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## Ken_K (Apr 16, 2020)

_@Ken_K is the 2" the one we need to be paying more attention to?_

I'm using the 2" temp. As someone else pointed out, seeds don't generally germinate 4-6" deep in the soil. If anyone else has a different view I'm all ears.


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## justinlmowery (2 mo ago)

Bombers said:


> Indaziflam (specticle or esplanade 200 sc) is better than simazine and lasts longer. I'll also relay the sentiment that you need very little. With Esplanade you only need .161 oz/1k yearly max. 1 oz of product will last your yard 3 years! With only 2k of lawn, you can buy a small split in the marketplace of either really and see how it works wonder when stacked with prodiamine.


 how did you calculate this?


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## justinlmowery (2 mo ago)

Bombers said:


> Indaziflam (specticle or esplanade 200 sc) is better than simazine and lasts longer. I'll also relay the sentiment that you need very little. With Esplanade you only need .161 oz/1k yearly max. 1 oz of product will last your yard 3 years! With only 2k of lawn, you can buy a small split in the marketplace of either really and see how it works wonder when stacked with prodiamine.


How did you calculate this rate?


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## Bombers (Jul 14, 2020)

justinlmowery said:


> How did you calculate this rate?


Esplanade 19.05% concentration. S-Flo 7.4%. About 2.57x more concentrated.

Although I also did the math for lbs of AI per gallon they listed. Esplanade has 1.67 lbs/gal. S-Flo has .622 lbs/gal. That came out to ~2.68x. Negligible.

Then did some excel math to match the yearly max rate for S-Flo which is approved for residential lawns (esplanade's rate is for industrial usage) to come out with that number. Works extremely well for 1.5 years so far with only a handful of weeds. I currently stack it with only simazine for fall to target POA and at one point simazine and prodiamine when I had some leftover.


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