Unusually cool August. When should I start thinking about Pre-Emergent?

Kentucky bluegrass, Fescue, Rye and Bent, etc
Leifcat1
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Unusually cool August. When should I start thinking about Pre-Emergent?

Postby Leifcat1 » August 12th, 2017, 7:32 pm

With the unseasonably cool nights we've been having since late July, is it too early to start thinking about fall Pre-Emergent? This fall will be my first time using Prodiamine and I'm worried about applying it too late. Everything I've read says to wait until around Labor Day, but with the recent string of cool temps, I'm worried that poa annua could start germinating earlier this year. I realize the temps could swing back up past 90 at any moment, however I just wanted to get the opinions of others on this site.

Note: I live in NW Iowa.

Thanks!
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andy10917
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Re: Unusually cool August. When should I start thinking about Pre-Emergent?

Postby andy10917 » August 12th, 2017, 7:52 pm

The only "harm" in going early is that you may need a second application if the first one wears off before the Poa Annua germination period ends. When is that? No exact date either.
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micvog
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Re: Unusually cool August. When should I start thinking about Pre-Emergent?

Postby micvog » August 12th, 2017, 7:56 pm

I just sprayed it last night at 0.75#/A and watered it in today (dragging hoses for most of the day).

What would be the benefit of waiting? You could do a heavier app if it is your first of the year, and either way you are covered for the rest of the growing season.
Leifcat1
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Re: Unusually cool August. When should I start thinking about Pre-Emergent?

Postby Leifcat1 » August 12th, 2017, 8:01 pm

I just did a light Tenacity app earlier today. Hopefully, that will buy me some time. I'd rather wait about two more weeks before dropping the pre-em.
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HoosierLawnGnome
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Re: Unusually cool August. When should I start thinking about Pre-Emergent?

Postby HoosierLawnGnome » August 12th, 2017, 11:01 pm

I put mine down end of July. I had time in what's been a crazy busy summer, and it's better early than late, particularly if you're doing split applications.

By the time you see weeds, it's too late IMO.

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PSU4ME
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Re: Unusually cool August. When should I start thinking about Pre-Emergent?

Postby PSU4ME » August 13th, 2017, 10:12 am

I just put my second app down last week, 1tbsp per k. Should last me to Decenber
Leifcat1
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Re: Unusually cool August. When should I start thinking about Pre-Emergent?

Postby Leifcat1 » August 15th, 2017, 9:48 am

Leifcat1 wrote:
August 12th, 2017, 8:01 pm
I just did a light Tenacity app earlier today. Hopefully, that will buy me some time. I'd rather wait about two more weeks before dropping the pre-em.
So yeah....just noticed a small patch of Poa Annua in the south facing part of the lawn. I don't think I'll be waiting a couple weeks to drop the Pre-Emergent.
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ken-n-nancy
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Re: Unusually cool August. When should I start thinking about Pre-Emergent?

Postby ken-n-nancy » August 15th, 2017, 8:43 pm

I'm quite a bit farther north than you, but my philosophy is to make two lower-rate applications for poa annua rather than a single higher-rate application.

My first fall application of prodiamine 65 WDG was at the end of July at the 3-month rate (0.5Tbsp/1K), with my second fall application just short of 2 months later, notionally planned for Sept 25th, again at the 3-month rate of 0.5Tbsp/1K.

Your applications are likely appropriate to be about a month or so later than mine. The Sept 25th application should last us until Christmas, at which point our ground is generally frozen for the winter (although not always...)
Leifcat1
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Re: Unusually cool August. When should I start thinking about Pre-Emergent?

Postby Leifcat1 » August 15th, 2017, 8:51 pm

ken-n-nancy wrote:
August 15th, 2017, 8:43 pm
I'm quite a bit farther north than you, but my philosophy is to make two lower-rate applications for poa annua rather than a single higher-rate application.

My first fall application of prodiamine 65 WDG was at the end of July at the 3-month rate (0.5Tbsp/1K), with my second fall application just short of 2 months later, notionally planned for Sept 25th, again at the 3-month rate of 0.5Tbsp/1K.

Your applications are likely appropriate to be about a month or so later than mine. The Sept 25th application should last us until Christmas, at which point our ground is generally frozen for the winter (although not always...)
I may use this method next season. Just out of curiosity, when do you apply your spring apps?
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ken-n-nancy
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Re: Unusually cool August. When should I start thinking about Pre-Emergent?

Postby ken-n-nancy » August 15th, 2017, 9:06 pm

Leifcat1 wrote:
August 15th, 2017, 8:51 pm
I may use this method next season. Just out of curiosity, when do you apply your spring apps?
I've been making just one spring app, targeted for about 2 weeks after Forsythia bloom. (Yes, I know standard practice is at Forsythia bloom, but I find that to just be too early for me here, so I've been going a couple weeks late, which seems to have been more effective.) For me, Forsythia usually bloom around April 15th, and I usually get a 3-month rate app of prodiamine 65 WDG down around May 1st. I applied May 4th in 2015 and April 22nd in 2016. This year, due to non-lawn commitments, I was even later, on May 10th 2017.
Leifcat1
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Re: Unusually cool August. When should I start thinking about Pre-Emergent?

Postby Leifcat1 » August 15th, 2017, 9:18 pm

Thank you. I'll probably give that schedule a shot next year. I'll feel better about using smaller but more-frequent applications.

I have 2.5 gallons of Prodiamine 4L and I only have 10k sq ft. This bottle should last me for the next 45 years. If anyone in my area wants any free of charge, I'm more than willing to share.

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