Fall Nitrogen Regimens

[Billybob]

I think he means not to push a lot of top growth after 1st frost. Hence the pause

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[andy10917]

I don't understand the pause. Here in central Virginia the first frost is usually mid October. But growth continues until usually the first part of December. That's almost 1.5 - 2 months of growth after frost, not a 3-4 week slowing down. The way I read your instructions is that there should be no fertilizer after frost until you make the winterizer application, which should be after growth stops but before the ground freezes.

If you know that your conditions are different, then adapt the program for your area as needed. Just make sure that it isn't continued fertilization that is keeping the grass growing. Are your neighbors all mowing into December? If so, then adapt the program. This isn't about hard deadlines - it's about feeding heavily, letting it go to sleep on it's own, and then winterizing when growth stops.

Please note that this program uses timeframes that are appropriate for many areas in the Northeast and North Central areas. Modifications may be needed if you are close to the shoreline or in the Transition Zone.

[virginiagal]

Okay. So the no fertilizer after frost isn't a rule but first frost is a general indicator for many areas on when to expect the slow down (and thus know not to fertilize). That's a good question on whether fertilization in late October could be pushing growth into December. I haven't been playing attention to when the neighbors stop mowing. It seems it would be prudent to do the last fertilization (other than winterizer) in the first half rather than the later half of October, if frost is expected mid-month. And maybe avoid slow release altogether in October?

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[andy10917]

There are no rules, other than to use your eyeballs and brain -- and apply local knowledge to make adjustments.

The Pause is designed to give the grass time to revert to its natural processes and slowdown.

I forgot to add something - the "aggressive" program is not that expensive to execute: with Urea going for $17 per 50 lbs this year, the cost of a 1 lb/K application of Urea is $0.34 per 1,000 sq ft. For a 5,000 sq ft lawn, that means it costs $1.70 per week to execute. If you have 7 weeks to first frost plus a full-winterizing application, the entire program costs $15.30.

I'm going to add that to the original posting...

[Wally]

Excellent post.

In regards to note #5, what was the thinking of the past on "Winterizer's"?

[gave20]

This same topic was discussed at length last year and has some good info to piggyback with this current topic.
http://aroundtheyard.com/post165437.htm ... ht#p165437

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[andy10917]

In regards to note #5, what was the thinking of the past on "Winterizer's"?

"Winterizer" fertilizers used to be high in Potassium and Phosphorus, and low in Nitrogen. Now, there is even some info that high Potassium in late-season may be a negative thing and increase the likelihood of Snow Mold. With Phosphorus bans, it has become Nitrogen + Potassium in many consumer products.

The below is from Colorado State -- read it with the perspective that many of the dates are accelerated due to the climate of Colorado.


The Myth Of Winterizer Fertilizer

[osuturfman]

Andy with the PGR I am using, Podium or generic Primo Max, I am told that the growth doesn't stop it is just redirected downwards.

It's the "I am told" part that concerns me. The manufacturers oversimplify stuff. PGR's work by being an "early" or "late" Giberellin biosyntesis inhibitor. Primo Maxx (and generic versions) are "late" Giberellin biosynthesis inhibitors. There is no magic to "redirect" growth - just no pressure to produce vertical growth. Now, that can mean better rooting and tillering since there is no pressure for vertical growth -- but I'm offering "be careful" caveats until I know that aggressive Nitrogen regimens are compatible with PGR's. I ain't betting on manufacturers' marketing drivel without real evidence.

Let's not get off-topic...

The energy is not "directly re-directed", it's just not used for the normal physiological process of producing shoot growth.

A couple of key points with PGR use and especially how to use them headed into autumn:

1.) Once you start apps during the season, DO NOT stop. The rebound effect, especially with Primo/Podium, is real and can throw the physiology of the plant for a loop if stopping and starting all the time. Lower rates and shorter intervals between are apps are ideal. The caveat here is you have to be irrigating and maintaining the turf to be green and growing all summer. If you're un-irrigated or let your turf go dormant just use Primo/Podium as an early season pre-stress conditioner.

2.) Heading into autumn, you want to time up your FINAL app to occur about 2 weeks before your first frost. The ideal scenario here is that the turf is still under regulation but, within a few days of coming out of regulation. Make the app too late and your "pause" will be like pressing "stop" for a month (trust me, I've done it). Too soon and you'll be hitting the rebound of the PGR with the first frost which in itself isn't a terrible thing but in my experience, not the best scenario. If you're looking for more info on how to time that app up please feel free to ask and I'll show you a rather simple way to calculate it within a reasonable window of time.

[virginiagal]

How would you adapt these guidelines to baby grass being planted now in an overseeding? Can new grass handle urea?

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[andy10917]

I like to be sure that Sprout-and-Pout is done before "pushing" young grass. I generally start applying Urea around Day 28-30, and I was very aggressive beyond that point. I had neighbors/friends (yes I have friends) swear I had installed a sod lawn at Day 60. It works well.

[tlinden]

Thanks! This explanation is very easy to follow.

[virginiagal]

I called Southern States yesterday to see if they had urea. Before they looked it up, they wanted my name and address. They had never asked me that when I had called about availability of stuff before. I wonder if I'm now in a database of "people inquiring about fertilizer." Anyway, they have 20 bags and price is $19.99.

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[ken-n-nancy]

There are actually three different periods in Fall, and applying Nitrogen during them is different for each one. ...

Early Fall
Where I live, this period starts around Labor Day. ... The idea is to have the last of the time-release Nitrogen peter out right around the time of average first-frost.

Mid-Fall/"The Pause"
You may wonder why I use the average first-frost date as a planning marker. After all, frost does not stop grass growth. That's all true, but first-frost date tends to precede the stoppage of top-growth in the lawn by 3-4 weeks.

When the first-frost occurs in your area, you want let the grass slow down the top-growth naturally -- continued Urea or AS treatments will force continued growth. ...

Average First-Frost Date by Zip Code

First off, thanks, Andy, for the excellent article summarizing Fall Nitrogen Regimens. I have found this article to be very educational and think it will be an excellent addition to the articles section of the site.

I do have a couple questions, though:

1 - What is the marker you use for the start of "The Pause" (the 2nd fall period)? In some places in the article (and in past posts of yours I was reading recently, when trying to learn about and plan my fall fertilizer applications), it seems like you use "average first frost date" as the start of the pause. In other places in the article, it seems like you are recommending the use of "first frost" (presumably the actual first frost) as this marker. Which do you use, or do you modify your plan a bit by what you observe about the lawn and the weather? The article could potentially use some clarification in this section, as it seems that some readers in their postings have focused on the "average first frost date" and others are focusing on the actual "first frost."

In any case, the "pause" is the tricky one, as it isn't directly determined by looking at the grass, as "the pause" starts about 3-4 weeks before the "slowdown/stoppage of growth." It's kind of like my recipe for toasting english muffins -- toast them until they start to get burnt but 30 seconds less. Alas, it isn't an easy recipe to follow, even though it is the right recipe (for the way I like my english muffins).

2 - Thanks for the link to Average First-Frost Date by Zip Code. That is a great resource for determining the likely date for first frost in a member's own area. However, which of the likelihood dates do you personally use for "average first frost date" -- the 50% Fall 32° date, or something else? Or, do you just use the dates for a general trend of when to expect the (actual) first frost (if you use the actual first frost as the marker in my question 1 above)?

Thanks!

PS: My impression from reading your other posts on this topic is that you would recommend the use of the "average first frost date" as the start of "the pause." This is the "50% Fall 32°" date from the tables at davesgarden.com, which is also the fall date in the first sentence of "Your results" on the davesgarden.com site, which reads "Each winter, on average, your risk of frost is from <insert date here> through <insert date here>." (For me in Bedford, NH (03110), that is September 21.)

[gendel]

Great article and please don't over do it with being too aggressive.
Just like people, lawns need a balanced diet, too. If you feed them too much, too little, or apply the wrong kind of fertilizer, they won't be healthy.
Phosphorus and potassium levels have to be adequate in the soil, for the mentioned nitrogen (N)fertelizer to be the most important nutrient for the fall.

[Pirate Russ]

Andy - Thanks for the article. Nonetheless, I have one question. If you use Milorganite, how many weeks should you leave between final milorganite application and the Avg First Frost Date?

[andy10917]

Just like people, lawns need a balanced diet, too. If you feed them too much, too little, or apply the wrong kind of fertilizer, they won't be healthy.
Phosphorus and potassium levels have to be adequate in the soil, for the mentioned nitrogen (N)fertelizer to be the most important nutrient for the fall.

Yup. This is why I stated that if you're on a soil remediation program, stay on it. High-Nitrogen can stress grasses if they are forced to grow from Nitrogen, without the other nutrients being available. Making good decisions toward a balanced soil is a critical step that can't be bypassed.

If you use Milorganite, how many weeks should you leave between final milorganite application and the Avg First Frost Date?

An extra week, if you want to be conservative.

What is the marker you use for the start of "The Pause" (the 2nd fall period)? In some places in the article (and in past posts of yours I was reading recently, when trying to learn about and plan my fall fertilizer applications), it seems like you use "average first frost date" as the start of the pause. In other places in the article, it seems like you are recommending the use of "first frost" (presumably the actual first frost) as this marker.

"First Frost" is the marker, but whether "actual" or "typical" is an on-the-spot decision for me. I look at how the Fall is proceeding and the 10-day temperature predictions and make up my mind -- no science or absolutes. After a couple of seasons, you'll just know and you'll be an expert for your area. Live and learn with your eyes and brain.

[dantis]

Great Article...and explains the browning I have going on which I though was mild disease..I will wait it out.

What is the opinion on using JDL starter fert to promote root growth now (SE Mass) and let "the pause" happen, then apply my 46-0-0 in mid-Nov??

In addition, am I wasting $$ and time if I do a Tenacity over spray on my Northern Mix front lawn to rid creeping bent and some Poa Annua then drop JDL 50/50 Rye/KBG seed (which I was happy enough with)? Is it too late to overseed and would my Fall N regime above be acceptable??

Thank you

[BoatDrinksQ5]

I would think the response the starter fertilizer is.... if determined by soil test.

But yes a typical storebrand fertilizer with fast and slow release - now ... and then a winterizer later when growth has stopped would work.

Killing undesireables/weeds is always a good call. I am always impressed with a mix or KBG lawn's repairability when you kill off other weeds. I wouldn't expect a huge need for seeding... by mid next spring it will be great.

[kevreh]

I have a two year old bag of fert with a good amount of slow release N in it. I also have my generic urea. I'm thinking of using the slow release in between the urea apps. Does this sound fine?

I'm waiting till the weather cools this weekend before doing my first fall app, and want the kick in the pants from urea, not a slow release.

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[andy10917]

I have a two year old bag of fert with a good amount of slow release N in it. I also have my generic urea. I'm thinking of using the slow release in between the urea apps. Does this sound fine?

Not really -- it's hard to figure out how much of the slow-release stuff is releasing at any moment, when you're pounding it with fast-release. The TOTAL amount released is the issue.

Either hold the slow-release for the Spring, or do "standard" N apps until 3-4 weeks past the last application of slow release. Don't try doubling-up...