# Should I scalp before spring preemergent applications?



## NCLawnLady (Jul 2, 2020)

Is it best to scalp your Bermuda prior to spring preemergent applications? Would it make a difference?


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## ionicatoms (Mar 8, 2020)

I don't think it makes a difference if you are watering in the pre-emergent.


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## FATC1TY (Jul 12, 2017)

Doesn't make a difference as long as it's getting watered into the soil.

I like to scalp and then apply, but I'm also scalping pretty low and in some instances, even taking up some dirt on the higher spots of my unlevel lawn. I like to think it's better to do after the scalp is possible/timed right.


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## Redtwin (Feb 9, 2019)

FATC1TY said:


> Doesn't make a difference as long as it's getting watered into the soil.
> 
> I like to scalp and then apply, but I'm also scalping pretty low and in some instances, even taking up some dirt on the higher spots of my unlevel lawn. I like to think it's better to do after the scalp is possible/timed right.


This is what I do as well. I think the product gets to the soil a little easier if you scalp first, but like mentioned above, as long as you water it in sufficiently it doesn't matter.


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## cldrunner (May 14, 2019)

I would apply the post emergent herbicide and kill those weeds first before scalping. @nclawnguy posted about having weeds in another post. If you scalp you will not have the leaf tissue exposed and taking care of the weeds is harder.


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## Jeremy3292 (Apr 30, 2020)

cldrunner said:


> I would apply the post emergent herbicide and kill those weeds first before scalping. @nclawnguy posted about having weeds in another post. If you scalp you will not have the leaf tissue exposed and taking care of the weeds is harder.


Interesting thought. I just bought some Negate for my Poa problem and was going to scalp, Negate, PreM graular all in the same day...


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## Redtwin (Feb 9, 2019)

I agree with @cldrunner. The scalp and PreM can be on the same day, but you are going to want leaf tissue for the Negate to soak into. Before the scalp would be best, but you could do it after if you allow the weeds to recover some tissue. My opinion is that the best practice is at least a week before the scalp.

I scalped and then put down pre-em. I am waiting to apply my post-em because the only weed I have that needs to be sprayed is Green Kyllinga. I am spot spraying Dismiss and don't want it affecting the green up so that will have to wait.


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## cldrunner (May 14, 2019)

@Jeremy3292 @Redtwin I am by no means an expert in Herbicide "ology". I am just trying to learn more everyday. Since you mentioned Negate I will clarify my statement. Some herbicides have *soil and foliar* activity. Negate is a sulfonylurea which has two active ingredients that are amino acid synthesis inhibitors that when applied to the soil will be activated by water into the soil.

*From Wikipedia*: Metsulfuron-methyl is an organic compound classified as a sulfonylurea herbicide, which kills broadleaf weeds and some annual grasses.[1] It is a systemic compound with foliar and soil activity, that inhibits cell division in shoots and roots. It has residual activity in soils, allowing it to be used infrequently but requiring up to 22 months before planting certain crops.

Rimsulfuron is a flexible herbicide in that it is both a pre-emergent and post-emergent herbicide. This gives the active flexibility in killing established weeds that have already germinated in an area, as well as keep weeds from growing in the first place.

From the label:Mode of Action: NEGATE 37WG contains Rimsulfuron and Metsulfuron-Methyl herbicides which belong to the sulfonylurea chemical family of herbicides. Herbicides in this family inhibit branched-chain amino acid synthesis in plants. NEGATE 37WG is absorbed through foliage of plants, rapidly inhibiting the growth of susceptible weeds.

https://www.domyown.com/msds/Detailer_Negate-1.pdf


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## Jeremy3292 (Apr 30, 2020)

cldrunner said:


> @Jeremy3292 @Redtwin I am by no means an expert in Herbicide "ology". I am just trying to learn more everyday. Since you mentioned Negate I will clarify my statement. Some herbicides have *soil and foliar* activity. Negate is a sulfonylurea which has two active ingredients that are amino acid synthesis inhibitors that when applied to the soil will be activated by water into the soil.
> 
> *From Wikipedia*: Metsulfuron-methyl is an organic compound classified as a sulfonylurea herbicide, which kills broadleaf weeds and some annual grasses.[1] It is a systemic compound with foliar and soil activity, that inhibits cell division in shoots and roots. It has residual activity in soils, allowing it to be used infrequently but requiring up to 22 months before planting certain crops.
> 
> ...


Yes, I actually purchased from domyown and was reading those labels beforehand. However, I do agree after more thought for maximum effectiveness I should probably give a week for foliar absorption and then root absorption will take over after that. Per UT (below) Negate is one of the best products for poa annua as it is an effective post emergent but also has some pre emergent effect for 6 weeks or so after.

http://www.mobileweedmanual.com/search-weed.aspx?SpeciesType=Turfgrass&PrePost=Post&TurfGrass=1&OrnamentalType=&Ornamental=&OrnamentalName=&WeedType=&WID=70


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## cldrunner (May 14, 2019)

@Jeremy3292 I think the bigger question is why did your Fall pre-emergent plan in August/September not do a better job of preventing the POA. Did you use more than one mode of action? What pre did you use?

I had very good results this year using Prodiamine/Isoxaben(broadleaf only), and Simazine.

In the Fall I am rotating to Spectilce Flo/Esplanade.

In the link you posted one of the herbicides that has peaked my interest for smaller lawns is a new herbicide mix called Coastal. It is a mix of prodiamine + imazaquin + simazine. With larger lawns it is more cost effective to just buy the 3 in larger quantities but for a smaller lawn it makes sense.

https://www.pestrong.com/1972-coastal-herbicide-simazine-prodiamine-imazaquin-05-25-gal.html
https://www.pestrong.com/file/3801-Coastal_Herbicide_Label

Disclaimer: I have never used Pest Strong. It was just a place I found it to be available and a label.

With a 6,000 sq ft lawn someone could get 3-4 years of a 3 mode of action approach for $100.


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## Jeremy3292 (Apr 30, 2020)

cldrunner said:


> @Jeremy3292 I think the bigger question is why did your Fall pre-emergent plan in August/September not do a better job of preventing the POA. Did you use more than one mode of action? What pre did you use?
> 
> I had very good results this year using Prodiamine/Isoxaben(broadleaf only), and Simazine.
> 
> ...


I am concerned about this as well as I did a split app of dithiopyr on approx Sept 5th and prodiamine on approx Nov 15th. Poa is a big problem in my area and I have had a lot of poa poke through now. The only thing I can think of is heavy rains caused a lot of leeching of my PreM. We tend to have wet winters here in upstate SC and my PreM worked for a while but then in the past month or so it's really gotten worse with the poa.

I actually just went outside this morning and put out an app of 0-0-7 prodiamine, roughly 4.5 lbs per 1,000 sq ft, just before it started raining. I am partial to granulars as I hate spraying and am ok spending more $ per app. However, I have heard of Coastal which is a relatively new herbicide I believe. I remember it being way more expensive than $99 so you have definitely peaked my interest on that.

My plan is as follows now:

Feb 26th: 0-0-7 prodiamine to get a new PreM barrier down (half annual max)
~March 1st: Negate to kill all winter weeds, mostly poa, chickweed, henbit, bittercress, and deadnette (the last 4 all look the same to me)
~March 10th: Scalp and bag clippings
~May 1st: 0-0-7 dithiopyr (split app)
~July 1st: 0-0-7 dithiopyr (split app)

I welcome any thoughts or comments.


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## Jeremy3292 (Apr 30, 2020)

As a follow up, I took screenshots from my Nest cams showing the increase of Poa over time starting end of Dec, end of Jan, and end of Feb (now). At first it was just the edges near the fence line which makes sense as there is a lack of bermuda there due to the shade or near the edges of the patio where I may not have applied it properly. But then it started to creep more towards the "middle or normal" areas of the yard which makes me believe it has leeched after rains and wet clay soil over 3-4 months.


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## cldrunner (May 14, 2019)

@Jeremy3292 Prodiamine(Group 3) and Dithyopyr(group 3) are the same mode of action. Your may have not applied fully to the edges

If you want to stay with granular I would look at adding Specticle G(Group 29) to your arsenal. . You may need to do a double pass on the edges. The soil around the edges and fence also warm up way sooner than the middle section of your grass.

I found Specticle G at SiteOne for about $101 for a 50 lb bag. A 50 lb bag would give you two Fall applications 45 days apart according to the label and I think that along with Prodiamine or Dithyopyr would be a good solution for the POA.


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