Final Urea App Question....

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Final Urea App Question....

Post by northeastlawn » November 25th, 2020, 11:32 am

Just curious if i should wait on my final urea app?

I have 0.7" of rain coming tomorrow. I have 3 days of 60deg, then a monsoon on 2" after that. I'd rather drop the urea for the 0.7" rain event as my sprinkler is turned off for the season.

On my last cut I had waited a week, and I was cutting about 1/4" off the tips at most and it didn't seem wide spread. Which seems to indicate it's still growing, but very slowly.

Will dropping the urea trigger top growth or is trace amounts of clipping enough to indicate the pause phase?

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Re: Final Urea App Question....

Post by MorpheusPA » November 25th, 2020, 2:46 pm

I'd say give a faint consideration to your temperatures. If they're holding sixty, the pause may reverse (it's not likely at November/December sunlight levels, which are abysmal, since not only are the hours limited at 9 maximum, the angle is very low at...math...about 25 degrees today at noon, fu...dge...more math...geez, we are in Solar Winter...24 degrees on Christmas Day) compared to (heck, yet more math) right around 70 degrees in late June. So relative solar power (0.4) stinks compared to summer's 0.95 and for a shorter time to boot.

And calculate the probability of the monsoon. While the urea will transfer over in 3 days, it won't completely absorb; some will get washed out. If that monsoon is highly probable, I might wait (I see a sixty percent chance of rain down here). Looking at the Boston forecast, that Monday rain is maybe, maybe not, and amounts are still up in the air depending.

If it were me? I'd probably pull the trigger. It's not perfect, but it's about as good as you can expect, my lawn is thick, and in 72 hours the grass should absorb a large percentage of the nitrogen. Monday's rain is not certain in amount or even if it's going to happen, and future temperatures show a progressive drop into late fall and winter.

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Re: Final Urea App Question....

Post by Bales9er » November 25th, 2020, 2:56 pm

I just finished dropping mine and I'm in Western MA, was debating the same thing but as Morph eluded to with future forecast temps it may be the last "best" opportunity for us without irrigation. I rolled the dice figuring worst case is it was juuust a smidge too early but still productive.

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Re: Final Urea App Question....

Post by northeastlawn » November 25th, 2020, 2:58 pm

Thanks for the suggestions.

I may have exaggerated the monsoon, they are predicting about 2", but that pretty much is as close to a monsoon as i have gotten all year :-)

Ill have to take another look at the weather and decide. I could technically run the sprinkler and just blow it out again, Im just trying to avoid that.

The 60deg predicted this weekend is kind of giving me the hint that I might want to take a chance and wait.

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Re: Final Urea App Question....

Post by MorpheusPA » November 25th, 2020, 3:45 pm

That with less math. :-)

I should add that "juuust a smidge too early" really isn't a problem. This is not surgery, which is fortunate. We don't have to be exact, we just have to get close. Even if you're a little early and only 98% of the nitrogen goes into storage and 2% goes into growth, it doesn't matter.

There's really no appreciable growth flush in November anyway, so have at. :-) Better a little too early than too late and miss the boat.


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Re: Final Urea App Question....

Post by Bales9er » November 25th, 2020, 3:51 pm

Agreed and well said Morph 👍

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Re: Final Urea App Question....

Post by Paul » November 25th, 2020, 3:53 pm

Drop it! The more you wait the more you risk cold temps with frozen ground that wont absorb anything. I dropped mine last weekend and had a nice rain the day after.

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Re: Final Urea App Question....

Post by northeastlawn » November 25th, 2020, 4:30 pm

[quote=Paul post_id=344839 time=1606334038 user_id=3972]Drop it! The more you wait the more you risk cold temps with frozen ground that wont absorb anything. I dropped mine last weekend and had a nice rain the day after.[/quote]

Really good point about the frozen ground, I never added that to the equation.

Two inches of rain over two days, isn't terrible if its already been watered in with about an 0.8" tomorrow.

After all who says any Urea you put down won't ben washed away, if you get a bunch of rain a week later.

This lawn stuff is complicated :-)

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Re: Final Urea App Question....

Post by SNOWBOB11 » November 25th, 2020, 10:32 pm

A lot of research now shows that a “winterizer” nitrogen app isn’t really necessary. Earlier in the fall the plant uptake is more than late fall and the result is it just sits on the soil until the grass resumes growth in the spring or leaches before that. With how difficult it can be to time your winterizer, research is leaning toward not needing to apply if you’ve properly feed earlier in the fall.

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Re: Final Urea App Question....

Post by Bales9er » November 26th, 2020, 7:50 am

Wheres the research to support that?

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Re: Final Urea App Question....

Post by andy10917 » November 26th, 2020, 10:24 am

When I was doing the research for the "Fall Nitrogen Regimens" approach and article (it took five years), I came across that research. Here's what I found:

A fair amount of the research took a perspective of "which is better - early Fall Nitrogen fertilization, or a single Winterization application in late Fall?".

And my own testing did prove out that they were right, if you stay strictly within the limits of the question they were addressing - a lawn will be better in the Spring with earlier Fall Nitrogen applications, when compared to a single late Fall winterization application.

But almost none of the research looked into the question of "what happens if you do *both* the early Fall applications and the winterization application?".

I tried answering the question myself through testing. I did an "early Fall only area", a "single winterization area", and an area that did both "early and late applications". There was no difference in the grass through the Winter, but the following Spring the grass woke-up a little earlier, was a little thicker, and lasted later into May in the areas treated with BOTH approaches. This was important since Nitrogen applications in Spring fertilize weeds as well as the lawn, and the later we deny Nitrogen to the weeds in Spring, the better the grasses are at competing and crowding out weeds.

Had the cost of Urea been high, I might have made a case for favoring "early Fall applications only", but Urea apps are quite inexpensive and there are some moderate differences in results. Remember that university researchers are considering the economic/budgetary factors on large-scale plots of land like golf courses and sports fields, and that isn't a major for the smaller amounts of plot size for residential lawn-enthusiasts. A moderate impact on results for $5 - $10 of Urea on a lawn is worth it to many of us. If that isn't your perspective, and you can only afford one or the other, I'd advise that you concentrate on early-Fall apps only. If the budget allows, do both and take the extra benefits.

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Re: Final Urea App Question....

Post by SNOWBOB11 » November 26th, 2020, 11:10 am

Bales9er wrote:
November 26th, 2020, 7:50 am
Wheres the research to support that?
It’s a fairly heavily debated topic as to whether it’s worth it or not. The general consensus at this time is not that a late application is bad for the grass or that there is necessarily a problem with applying it. It’s more whether there is much if any benefits over early spoon feeding and skipping the winterizer.

There has been a bunch of research done by Dr. Soldat in regards to this. Here’s a podcast that talks about it.

https://turfnet.wistia.com/medias/yq4djng1cb

If you don’t have time to listen to a hour long podcast here’s a article that is quicker to read that also talks about skipping the finale fertilizer app as most of it sits on the soil until spring or leaches.

https://turf.unl.edu/turfinfo/Fall%20Fertilization.pdf

This is the 4th fall since I did a renovation to KBG. The first 2 I applied a winterizer. Last year I skipped it and didn’t see any difference with how quick the lawn greened up. I skipped it again this season and I expect to see similar results.

With how difficult it can be to time the final winterizer app being irrigation is usually turned off by then, if it’s not going to give any real benefit the general idea is to skip it.

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Re: Final Urea App Question....

Post by northeastlawn » November 26th, 2020, 4:23 pm

All the above info has just made me appreciate the fall fertilizer program as a whole even if one or two parts can't be timed out perfect because of weather.

This my KBG lawns 3rd summer, this year it did much better in the summer and the weekly Urea apps just got it back to where it was in June. My last cut was 2" and i never had a lawn that was so full at 2" before. Come spring Im looking forward to some really good spreading and growth, just because of the feeding i did in the fall.

Maybe the winterizer is just icing on the cake, but I'm happy to be trying something to be a season ahead, as opposed to using next spring to repair last years summer damage, as has been mentioned Urea is pretty cheap.

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Re: Final Urea App Question....

Post by edslawn » November 26th, 2020, 10:22 pm

andy10917 wrote:
November 26th, 2020, 10:24 am
When I was doing the research for the "Fall Nitrogen Regimens" approach and article (it took five years), I came across that research. Here's what I found:

A fair amount of the research took a perspective of "which is better - early Fall Nitrogen fertilization, or a single Winterization application in late Fall?".

And my own testing did prove out that they were right, if you stay strictly within the limits of the question they were addressing - a lawn will be better in the Spring with earlier Fall Nitrogen applications, when compared to a single late Fall winterization application.

But almost none of the research looked into the question of "what happens if you do *both* the early Fall applications and the winterization application?".

I tried answering the question myself through testing. I did an "early Fall only area", a "single winterization area", and an area that did both "early and late applications". There was no difference in the grass through the Winter, but the following Spring the grass woke-up a little earlier, was a little thicker, and lasted later into May in the areas treated with BOTH approaches. This was important since Nitrogen applications in Spring fertilize weeds as well as the lawn, and the later we deny Nitrogen to the weeds in Spring, the better the grasses are at competing and crowding out weeds.

Had the cost of Urea been high, I might have made a case for favoring "early Fall applications only", but Urea apps are quite inexpensive and there are some moderate differences in results. Remember that university researchers are considering the economic/budgetary factors on large-scale plots of land like golf courses and sports fields, and that isn't a major for the smaller amounts of plot size for residential lawn-enthusiasts. A moderate impact on results for $5 - $10 of Urea on a lawn is worth it to many of us. If that isn't your perspective, and you can only afford one or the other, I'd advise that you concentrate on early-Fall apps only. If the budget allows, do both and take the extra benefits.
Great points! Thanks again for all you do Andy (and same to the rest of the experienced contributors who helps out) ... I have learned so much from this site. I also accept a diversity of opinions as we all work through the unique challenges of climate, turf types, personal goals, and budgets for our lawns. The basics are simple, but after that, it gets challenging out there :good:

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Re: Final Urea App Question....

Post by MorpheusPA » November 26th, 2020, 11:19 pm

Looks at lawn...looks at PDF...

This isn't Nebraska, which does feature a very different climate than I have (Hot summer humid continental versus my Oceanic), so there are certainly going to be different recommendations state per state. (That was a quick lookup off the Koeppen Climate Types, which I actually hate as being way too general).

People tell me I ramble on too much. So, to de-ramble, comparing general weather, humidity, and whatnot in November versus Omaha and points north (which is what the PDF discusses), versus mine...on balance and not discussing plenty of data points (rolling up the vector, in other words), I simply don't have the same considerations they discuss, or the same nitrogen uptake issues or challenges. I'll continue to winterize. My November is their October--at worst.

We won't discuss the weaknesses of the article because...I simply shouldn't have to.

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Re: Final Urea App Question....

Post by SNOWBOB11 » November 27th, 2020, 12:31 am

I don’t think the article has weakness at all. Just newer way of thinking about late nitrogen.

The difference between areas shouldn’t matter in terms of climate more than soil type. A sandy soil would hold onto even less late nitrogen than a less sandy soil.

You can ask yourself have you ever actually skipped the winterizer app and if so was there a big difference in the spring? Or could you just apply a spring app and have the lawn just as green?

Nothing wrong with looking at information from a turf professional who has done much testing on the matter.

Also good to look at your own results and as I said I’ve noticed no difference. I mean I could throw out some alfalfa meal in January on top of 2 feet of snow and hope it eventually gets to the lawn in spring and it won’t harm anything but is it really necessary or worth it? Probably not.

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Re: Final Urea App Question....

Post by bpgreen » November 27th, 2020, 1:56 am

SNOWBOB11 wrote:
November 27th, 2020, 12:31 am
I don’t think the article has weakness at all. Just newer way of thinking about late nitrogen.

The difference between areas shouldn’t matter in terms of climate more than soil type. A sandy soil would hold onto even less late nitrogen than a less sandy soil.

You can ask yourself have you ever actually skipped the winterizer app and if so was there a big difference in the spring? Or could you just apply a spring app and have the lawn just as green?

Nothing wrong with looking at information from a turf professional who has done much testing on the matter.

Also good to look at your own results and as I said I’ve noticed no difference. I mean I could throw out some alfalfa meal in January on top of 2 feet of snow and hope it eventually gets to the lawn in spring and it won’t harm anything but is it really necessary or worth it? Probably not.
Did you read Andy's post? If so, did you understand it?

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Re: Final Urea App Question....

Post by Green » November 29th, 2020, 3:19 am

Very interesting discussion here. I've been following the studies myself for a couple of years now. As I see it, the major issue in question indeed boils down to "how much Nitrogen gets taken up, and how much does not". And there have been an experiment or two using labeled N to discern that. As you'd expect, the colder it gets, the lower the evapotranspiration becomes, and that is correlated directly with N uptake.

But what I found, is that these studies are often putting a full spoonfeeding program up against a final late season app. Instead of having a pause, they consistently reduce the amount of N applied, and keep spoon feeding until growth stops. It's ok to do that because they are tapering down to miniscule doses by the time growth stops, and they're probably doing so because they're more often studying sand based systems which are low in organic matter and have trouble holding nutrients. It can be overkill on a home lawn with a good loam, not to mention too much labor when you have leaves to mulch in, wind to deal with preventing weekly spraying, etc. So, we don't generally do those tapered spoonfeeding programs often on home lawns. You can, if you want to, though.

However, I said to myself, what if I could sort of simulate that spoonfeeding by using a Nitrogen source that would reduce its own delivery as the microbes slowed due to temperature? In other words using microbial action as a proxy for growth rate.

I mentioned it last year, but said I didn't feel ready to talk a lot about it back then. A year has gone by. I feel like I can say more about my experiment now, since I'm in the middle of it as we speak and there is more research out there now so my experiment won't be dismissed easily by most people. I'm testing a beginning-of-the pause winterizing app with an altered formula (microbial breakdown-induced N source) against my previous formula and timing (end of season timing, mostly fast release formula).

There is a whole complicated backstory that led me to do this experiment. My experiences over the past 8 years have been what led me to do this. I'm extremely excited to see if there are any differences in Spring results. So far, there are no observable differences. My test app went down in late October (a week later than I wanted going strictly by weather, soil temps, and growth rate, but life happens). My other area's fertilizer (default final winterizing app) has not gone down yet, but will soon.

Also, inspired by a post above by Andy, I may add a test section: my experimental formula and timing plus the standard final urea app.

Exciting times...

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Re: Final Urea App Question....

Post by andy10917 » November 29th, 2020, 10:51 am

It's good to see additional folks experimenting and publishing their results, Sometimes I wonder about whether all the experimentation I do has made my soil different than the soil of other members, which might lead to them not getting the same results I do. Many years of mulching 24" - 30" of leaves per year and several years of humate supplementation probably makes my soil hold more than people that are less aggressive can hold. Does that affect results and the optimal point of Nitrogen? I don't know, but I scan the postings for reports of empirical outcomes to see what happens on others' lawns, not just mine.

In a broader picture that you touched upon, I know that trying to take the results of sand-based "soil" (golf greens, etc) and replicate the outcomes on loam-based soils (residential lawns) has a very-low success rate.

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Re: Final Urea App Question....

Post by MorpheusPA » November 29th, 2020, 11:05 am

I'm sort of wondering why we expect measurable differences when dumping around 3 pounds of nitrogen in fall, whether that's early or late, as long as it gets done on a reasonable schedule. (Note that isn't a question as, frankly, I don't expect much difference and my working hypothesis would be that there wouldn't be much of one). Year on year, that's borne out by years where I missed the last fertilization and years I didn't. While that costs a pound of N, spring green-up doesn't change much in the sense that the lawn really doesn't go brown anyway.

Personally, I think color is superior and thickness is better through spring and self-repair better as well, but... One has to be careful of confirmation bias.

My limited and rather icy critique of uptake timing above being entirely different; we're careful to specify "topgrowth stoppage" for last application, which sure ain't gonna be when temps are topping 32 in Omaha, as they are now in late November (and uptake of N is practically zero). Enough said on that. But, as noted, Omaha isn't Philadelphia, where it's pushing sixty again today. One's last chance app of N is probably, for Philly, in fact--today. We're expecting an inch of rain tomorrow, then the final drop into late fall temperatures. I still have a few blooming flowers in the garden.

At heart, I'm two parts scientist and about 1.5 parts artist (yeah, seriously, I do better at logic than art). But there are times when you play Follow Your Heart more than follow the calendar, and that last feed is one of them.

Is some nitrogen lost? Sure, it always is. No argument there. Is it lost at the rate of November in Nebraska on sand? No, because we're applying it long before that level of temperature/biological inactivity of the lawn and we're not working on sand.

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