# Pre emergent schedule



## Cincinnati guy (Mar 6, 2018)

What does your pre emergent schedule look like? Back in March I put down a dose of lesco deminsion with fertilizer, now I'm slowly starting to get some weeds growing again in my lawn. I plan to overseed in August. Would it be advisable to do a shot of pre emergent again so I can overseed in august?


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## Miller_Low_Life (Apr 12, 2017)

I would say you're ok to put some down within the next couple of weeks. That shouldn't interfere with your seeding. How bad are the weeds though?


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## Cincinnati guy (Mar 6, 2018)

The weeds are not extremely bad but more then what I am wanting! I've worked hard last fall getting the yard the way it is to have weeds overtake. Will preemergent effect how effective nutsedge killer will work if put down at the same times?


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## g-man (Jun 15, 2017)

I would not apply prem anymore if you want to overseed. Treat the weeds that show up with postm


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## jha4aamu (Oct 16, 2017)

g-man said:


> I would not apply prem anymore if you want to overseed. Treat the weeds that show up with postm


similar question to cincy guy's, but i missed my fall '17 overseed and preM and i had some heavy Poa A this spring. I dont want to end up w/ more Poa A next year but I also need to overseed too. Whats a timeframe and/or preM that would make this possible?


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## g-man (Jun 15, 2017)

The only option for jha4aamu is to use tenacity at seed down and then 30days later. I think that places you in a position that you might be able to apply prodiamine. It all depends on when you plan to overseed and how the weather is like.

If you have KBG, then there is no need to overseed. Just feed it nitrogen and it will fill in.


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## jha4aamu (Oct 16, 2017)

planned on seeding 9/8. so prodiamine app 2 months after seed down?


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## g-man (Jun 15, 2017)

Check the label for prodiamine, but I think it is safe 60 days post emergence.


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## Suburban Jungle Life (Mar 1, 2018)

For TTTF, I do what g-man said. I use tenacity at seed down and 30 days later. This gives 2 months of protection before switching to prodiamine. I do a prodiamine app at 60 after seed down and then another app in spring. For TTTF, I also use ethofumesate (poa constrictor) at seed down, 30 days after, and once in spring. This in combination with the tenacity schedule works well to control poa. This plan doesn't fit if seeding KBG though.


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## Ballistic (Mar 19, 2018)

You may want want to look into Tenacity, I believe it can be used even at the time of seeding.


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## jimmy (Jul 25, 2017)

g-man said:


> If you have KBG, then there is no need to overseed. Just feed it nitrogen and it will fill in.


For @jha4aamu, this is the answer.


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## jha4aamu (Oct 16, 2017)

Suburban Jungle Life said:


> For TTTF, I do what g-man said. I use tenacity at seed down and 30 days later. This gives 2 months of protection before switching to prodiamine. I do a prodiamine app at 60 after seed down and then another app in spring. For TTTF, I also use ethofumesate (poa constrictor) at seed down, 30 days after, and once in spring. This in combination with the tenacity schedule works well to control poa. This plan doesn't fit if seeding KBG though.


any particular reason why this plan wont work for kbg or prg?


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## Suburban Jungle Life (Mar 1, 2018)

jha4aamu said:


> Suburban Jungle Life said:
> 
> 
> > For TTTF, I do what g-man said. I use tenacity at seed down and 30 days later. This gives 2 months of protection before switching to prodiamine. I do a prodiamine app at 60 after seed down and then another app in spring. For TTTF, I also use ethofumesate (poa constrictor) at seed down, 30 days after, and once in spring. This in combination with the tenacity schedule works well to control poa. This plan doesn't fit if seeding KBG though.
> ...


The problem is ethofumesate. You could skip this but it really helps with poa. It has different seeding intervals for bluegrass and ryegrass. For bluegrass, you have to wait 8 weeks to apply after emergence of the new grass. That doesn't fit too well into this schedule. Probably because poa annua is also a bluegrass and too close in dna to poa pratensis, the desired bluegrass. Though as others have stated, if you have bluegrass, it spreads so you only need to fertilize it. Fescue and rye don't so they need to be seeded and ideally every year since some of the plants die and eventually will leave the turf thinner over the years.

The problem is poa annua germinates once summer temps come down so that is also the optimal time to seed other grass. How do you stop poa from germinating but not your desired grass seeds? Once the weather cools, using these herbicides to control poa while allowing desired grasses to germinate before switching to a non selective type of pre-emergent is the way to get around this problem. If you have KBG and it has decent coverage, you just use prodiamine year round and not worry about seeding anything. You can also transplant plugs to help with this.

PRG has a 2 week wait before and after germination. So spray and 2 weeks later, seed. Then 2 weeks after, spray again. This will allow the 2 apps to be done before switching to prodiamine.


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## Green (Dec 24, 2017)

g-man said:


> I would not apply prem anymore if you want to overseed. Treat the weeds that show up with postm


I disagree. If you know from experience how long your pre-M lasts, you can still apply a low rate (for Dimension, not Prodiamine).

I still have an area that I will be applying a low rate of Dimension on, the beginning of next week (middle of the month). We're only halfway to seeding time in my area, so I know from experience that I can sneak in a half app of 0.15% granular Dimension at this time. However, I don't think I'd push it past mid June. I'll be applying 2 lbs/K. Normally I'd have used 4 lbs/K in mid April.


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## jimmy (Jul 25, 2017)

Green said:


> g-man said:
> 
> 
> > I would not apply prem anymore if you want to overseed. Treat the weeds that show up with postm
> ...


I found in my renovation last fall, that my pre-emergent still remained in some areas of my yard, but was degraded in others. It was the shadiest areas that I had zero growth. I would have expected _some_ growth, even in the shade, but the prodiamine degrades much more slowly in shady areas. I also may have applied a slightly heavier rate since it was my first time using that backpack sprayer and I started in that corner of the yard.

Not telling the OP what to do here, but that conditions and chemicals remaining can be different if different areas, even in the same yard.


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## Green (Dec 24, 2017)

jimmy said:


> I found in my renovation last fall, that my pre-emergent still remained in some areas of my yard, but was degraded in others. It was the shadiest areas that I had zero growth. I would have expected _some_ growth, even in the shade, but the prodiamine degrades much more slowly in shady areas. I also may have applied a slightly heavier rate since it was my first time using that backpack sprayer and I started in that corner of the yard.
> 
> Not telling the OP what to do here, but that conditions and chemicals remaining can be different if different areas, even in the same yard.


Great tip! Some people don't even apply pre-M in shady areas because crabgrass doesn't like shade.


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## FuzzeWuzze (Aug 25, 2017)

Green said:


> g-man said:
> 
> 
> > I would not apply prem anymore if you want to overseed. Treat the weeds that show up with postm
> ...


True, but are you willing to risk hundreds of dollars in seed? 
I mean if you could just go look at your yard and see "Yup its worn off", but you cant..so its always a gamble.


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## Green (Dec 24, 2017)

FuzzeWuzze said:


> True, but are you willing to risk hundreds of dollars in seed?
> I mean if you could just go look at your yard and see "Yup its worn off", but you cant..so its always a gamble.


I'm not anticipating much seeding this year, and I can tell when it wears off by weed breakthrough along the edge. THe remaining barrier can be broken up easily at that point. Of course...Only do this if you're pretty confident it will work!


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