Tenacity Pre-em

Kentucky bluegrass, Fescue, Rye and Bent, etc
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bolson32
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Tenacity Pre-em

Post by bolson32 » May 5th, 2022, 2:36 pm

So, I dormant seeded last fall and while it was probably a waste of time, I want to give it a chance to come up this spring and use tenacity as a pre-em.

I have a pretty typical NoMix KBG, Rye, and overseeded with TTTF. I saw in another post that 16oz per acre is going to hurt/kill anything that's not KBG. Would 3oz per acre be an appropriate application amount as a pre-emergent in this use case? I have a ton of grassy weeds so I know it's going to look quite bleached after this first app and I'm wondering how the best way to go about this might be.

I live in the Twin Cities and we're a good 3 weeks behind normal years so far here but it's looking like we might just skip spring and go right from winter to summer. It was in the '40s all last week and we'll hit 80 next week.

Green
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Re: Tenacity Pre-em

Post by Green » May 6th, 2022, 12:22 am

I've done 3oz per acre for this purpose, but I prefer 4oz if possible as it's more effective and lasts longer. If I'm applying to fine fescue, which is sensitive, I only do 2-3 oz/A. If you really want it to work well and last as close as possible to the full 4-6 weeks without doing the 8oz/A rate, you can try 5-6 oz, which also works well.

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ronfitch
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Re: Tenacity Pre-em

Post by ronfitch » May 6th, 2022, 9:50 am

bolson32 wrote:
May 5th, 2022, 2:36 pm
So, I dormant seeded last fall and while it was probably a waste of time, I want to give it a chance to come up this spring and use tenacity as a pre-em.

I have a pretty typical NoMix KBG, Rye, and overseeded with TTTF. I saw in another post that 16oz per acre is going to hurt/kill anything that's not KBG. Would 3oz per acre be an appropriate application amount as a pre-emergent in this use case? I have a ton of grassy weeds so I know it's going to look quite bleached after this first app and I'm wondering how the best way to go about this might be.

I live in the Twin Cities and we're a good 3 weeks behind normal years so far here but it's looking like we might just skip spring and go right from winter to summer. It was in the '40s all last week and we'll hit 80 next week.
Heard on MPR (Mark Seeley) just this morning that as a state, the first four months of the year in Minnesota had colder-than-normal high temps (and half the days experienced wind gusts of at least 30 mph, which has never been recorded ... and, there will be one last weekend of skiing in Lutsen as they still have three feet of snow in some areas, the latest skiing since WWII).

Ground temps at the four inch depth were rising through the 40s and hit 50 three weeks ago, but started to backtrack. The temps at the four-inch depth have been in the 50s for the past week for me, just east of St Paul.

bolson32
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Re: Tenacity Pre-em

Post by bolson32 » May 6th, 2022, 12:07 pm

It sure has been a crappy spring!

Although with 80s showing Monday I think it's going to be pre-em time pretty quick. Soil temps at the surface were 55 yesterday for the first time in my zip code I think.

zhotster
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Re: Tenacity Pre-em

Post by zhotster » May 8th, 2022, 9:43 am

I am living this, I dormant seeded right before winter and I'm not far from the OP. I bit the bullet and put Pre-emergent down today. Like a lot of folks here, the spots I dormant seeded were near my driveway or curb. I just couldn't hold myself back from putting down the Pre-M and will do some extra watering to help those dry areas and hope they will fill in. Next week it's going to be in the 80's, going straight from winter to summer, it's nuts!


bolson32
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Re: Tenacity Pre-em

Post by bolson32 » May 10th, 2022, 4:06 pm

Based on Green's advice I went in the middle. Put down about 5oz over ~57k sq ft. Which comes out to about 3.75oz an acre or somewhere thereabouts.

Next question, which is probably splitting hairs, how long should I wait to mow? Conventional wisdom for foliar-applied herbicides is 48 hours, but since we're trying to work it down into the soil anyway can I just mow tomorrow before it rains tomorrow night? We're getting a little shaggy and tomorrow would be ideal given the incoming rain and compatibility with my schedule. Or should I wait until it rains and the mow sometime Thursday?

Green
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Re: Tenacity Pre-em

Post by Green » May 10th, 2022, 11:14 pm

Mow after about a day if you have to. Otherwise, give it 2 days.

I like using Tenacity this time of year as a combined temporary pre-M and post-M in one to hold me over. That way, being late with a regular pre-M has virtually no consequences, since the post-M feature of the Tenacity also gets any small Crabgrass that's starting to germinate now.

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ken-n-nancy
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Re: Tenacity Pre-em

Post by ken-n-nancy » May 11th, 2022, 6:39 am

bolson32 wrote:
May 10th, 2022, 4:06 pm
Next question, which is probably splitting hairs, how long should I wait to mow? Conventional wisdom for foliar-applied herbicides is 48 hours, but since we're trying to work it down into the soil anyway can I just mow tomorrow before it rains tomorrow night? We're getting a little shaggy and tomorrow would be ideal given the incoming rain and compatibility with my schedule. Or should I wait until it rains and the mow sometime Thursday?
Personally, when the grass is really growing, I mow on a schedule of every third or fourth day. I usually will make foliar herbicide applications the day after mowing, which gives it one or two days to work before cutting off leaf surface. I've generally had good success with this approach.

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