# Overapplied Prodiamine



## HadaGreatLawn (Apr 8, 2021)

Hello,

So i thought i did everything right before attempting my first spray application of Prodiamine. Bought a battery backpack sprayer, got some aftermarket nozzles, and practiced with some RGS and Air8 applications last week. Also calibrated the sprayer using a 1000 square foot section of my driveway. Timed everything and felt pretty confident going into my first pre-emergent treatment. Final step, bought a digital scale from Amazon.

Decided on a split app (figured if i screwed something up, this was the safest) at .185oz/1000. I have a 20k KBG mix in southeast Wisconsin. The scale i bought only displayed tenths of an ounce (0.1 or 0.2). I figured this wasn't accurate enough since 0.2 could fall somewhere in between 0.15 and 0.24 because of rounding. Figured no problem, i'll switch to grams and use Google to convert. 0.185oz = 5.2g. Here's where the problem happened. This same scale that displays every other measurement to tenths apparently only does whole numbers for grams. To make matters worse, the little g for grams is inconveniently displayed at the bottom in between two numbers, basically looking like a decimal place. So instead of applying at a rate of 5.2g/1000, i applied 10X that at 52g/1000.

I guess it could've been worse had i decided to apply at full rate instead of doing split apps. So by my calculations, I am somewhere close to 5X the max rate for the entire year.

What can i do to salvage my lawn? It was coming out of winter dormancy beautifully. Its a two year old lawn that I core aerated, detached, top dressed with compost, and overseeded last August. By October, I had the nicest lawn in the subdivision.

Im reading that microbes help break this stuff down along with light. Should i mow low and apply heavy milorganite? Would aerating now help? Ive also read some other forums to try and push a lot of RGS. How often can I apply RGS and at what rate? Ive been researching this since i realized my mistake last night I haven't found any specific examples for KBG so I am hoping you can offer some insight.

Ive been watering all night long and we have rain in the forecast for the next 72-96 hours.


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## M32075 (May 9, 2019)

It will kill young grass other than that I don't see the harm. You can pass up the second app I'm thinking &#129300;


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## HadaGreatLawn (Apr 8, 2021)

M32075 said:


> It will kill young grass other than that I don't see the harm. You can pass up the second app I'm thinking 🤔


How young is young? I mowed my overseed 4 or 5 times before the cold set in last fall.


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## g-man (Jun 15, 2017)

You are not the first one to post something like this. 10x is a lot and i think the lawn will suffer. The problem is that all that have over applied, never return to give us an update. More water won't help. Maybe activated carbon could help.


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## M32075 (May 9, 2019)

HadaGreatLawn said:


> M32075 said:
> 
> 
> > It will kill young grass other than that I don't see the harm. You can pass up the second app I'm thinking 🤔
> ...


I think it's mature enough to survive. Watering won't help much prodiamine attaches it self to the soil only time will break it down. Dimension can be broken down by water. I think I read that prodiamine can stunt root growth on new grass not positive on that.


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## g-man (Jun 15, 2017)

It can stunt growth on mature too.


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## HadaGreatLawn (Apr 8, 2021)

g-man said:


> You are not the first one to post something like this. 10x is a lot and i think the lawn will suffer. The problem is that all that have over applied, never return to give us an update. More water won't help. Maybe activated carbon could help.


What do you recommend for activated carbon? Would you try to push growth with milorganite? I'll post updates throughout the season.


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## M32075 (May 9, 2019)

I read in another forum that microbes activity can break it down and the guy really seemed knowledgeable . Dropping some Milo and mulch mowing can't hurt worth a try. You could also send a email to the manufacturer with your situation they should have some good information for you.


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## Dkrem (Mar 16, 2019)

About all you can do it wait it out and treat any symptoms that appear.


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## HadaGreatLawn (Apr 8, 2021)

So my plan is to do an app of RGS/Humic/Air8 this evening. We are supposed to get another 1/2"of rain tomorrow so that'll help get this stuff down to where it needs to be. I ordered Sea-K as well. I'll re-apply the above at 3oz/1000 rates every two weeks for the foreseeable future. Its supposed to cool down in Wisconsin to daytime temps in the low 50s and nights in the mid 30s so I am holding off on any nitrogen for now. I was low on P and K on my soil test so I'll do a starter fert along with milorganite around May 1st. Thankfully, they practically give away milorganite in Wisconsin (normal retail is $8.99 but on they always go on sale around Memorial Day/4th of July/Labor day for 5 bag for $30). I plan to spoon feed milo throughout the season and supplement with some synthetics too.

Added the picture of my lawn so we have a documented starting point. It needs a mowing but its pretty soggy out there. I'll try to post updates every couple of weeks unless something changes significantly.

Thanks for all the feedback so far.


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## HadaGreatLawn (Apr 8, 2021)

3 weeks since the overdose. No ill effects that I've noticed. I haven't fertilized yet and decided to just maintain my normal routine. I did put down gypsum about a week ago since I am trying to slowly amend my heavy clay soil. I will be due for another round of RGS/Humic 12 next weekend. I might fertilize then too. I am planning on spraying 2,4-d this weekend. Still debating on whether to do a blanket app or just spot spraying. I have a bunch of weeds from last year when the section closest to the pond was seeded. I didn't have a chance to spray in the fall since the grass was young and I decided to do a full topdress and overseed. I'll post another update in a couple of weeks or so.


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## Bob38 (Jun 4, 2021)

Hey I did the same thing. So how is your lawn doing? Does it show any signs of stress?


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## CanadianGrassMan (Apr 25, 2020)

Beautiful strips


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## jeffjunstrom (Aug 12, 2019)

Those stripes are on point. I wish I had your sense of direction, balance, and order.


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## thin_concrete (Sep 11, 2020)

@HadaGreatLawn - that looks fantastic (post on 29 APR)! What striping kit are you using?


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## Lawn Whisperer (Feb 15, 2021)

WOW!!! :shock: How do you keep those lines so straight?

Do you think the over application of pre-emergent had much negative effects on root growth? Are you having to water more often?


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## HadaGreatLawn (Apr 8, 2021)

Lawn Whisperer said:


> WOW!!! :shock: How do you keep those lines so straight?
> 
> Do you think the over application of pre-emergent had much negative effects on root growth? Are you having to water more often?


That was a 21" Honda HRN217 mower without a striping kit. I just take my time mowing, focus on a fixed point in the distance and try to follow the previous stripe as long as it's straight. I have now upgraded to a Ferris FW15 with a checkmate so my stripes have gone to the next level.

As for updates to my prodiamine mishap, hard to tell what the effects were of my overdose. We had a terrible summer in SE Wisconsin between drought and heat. I had a lot of issues with fungus and am not sure if that was due to the effects of prodiamine, mother nature, or both. The pics are from Memorial Day when my lawn was at its peak. It went downhill from there.


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## HadaGreatLawn (Apr 8, 2021)

June 27th pics below. Started going downhill fast. I applied propiconazole but i think too was late (planning on doing preventive apps going forward beginning next year). I have really bad drainage in the backyard too. I'll update this weekend what it looks like in its current state. Started the fall blitz already and this weekend will be round 2 so I am hoping the damage shows signs of repair by Labor Day or I will have to overseed. My main problem areas are in the back and the prodiamine OD was on the entire lawn. So i am really thinking my issues are more from drainage then anything since the front yard still looks pretty decent. More updates to come this weekend.


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## g-man (Jun 15, 2017)

You won't need to overseed. Water + nitrogen and this should recover.


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## HadaGreatLawn (Apr 8, 2021)

g-man said:


> You won't need to overseed. Water + nitrogen and this should recover.


I hope you're right. Pictures from previous post are almost 6 weeks old and those spots got exponentially worse. I'll post some current aerial pics this weekend of the entire lawn but this should give you an idea of the severity. There is some green in there so hoping it's enough that the blitz will fix it.

The main spot (two angles of it taken) is where I had all the lumber stacked for when my deck was built this February. Guessing that really compacted things. Aeration is on the table for sure. Front lawn looks to be normal drought/heat stress so not worried about that at all.


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## keneil01 (Sep 15, 2019)

Any updates on the overdose of prodiamine?


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## HadaGreatLawn (Apr 8, 2021)

keneil01 said:


> Any updates on the overdose of prodiamine?


Back to normal. Did the nitrogen blitz and it helped it recover from fungus, summer heat/drought and any effects of the prodiamine OD


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## VALawnNoob (Jun 9, 2020)

Is it fair to assume you had NO weeds this season? :lol:


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## HadaGreatLawn (Apr 8, 2021)

VALawnNoob said:


> Is it fair to assume you had NO weeds this season? :lol:


ZERO crabgrass in the turf which is crazy considering both my neighbors had major issues. As for weeds in general, I had more weed pressure this fall then I ever have but one blanket application of speedzone fixed that. I skipped the fall pre-emergent app so I expect some issues next spring but I'll just deal with it then.


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