Fall Nitrogen Regimens

Kentucky bluegrass, Fescue, Rye and Bent, etc
Post Reply
User avatar
andy10917
Posts: 29116
Joined: February 23rd, 2009, 10:48 pm
Location: NY (Lower Hudson Valley)
Grass Type: Emblem KBG (Front); Blueberry KBG Monostand (Back)
Lawn Size: 1 acre-2 acre
Level: Advanced

Fall Nitrogen Regimens

Post by andy10917 » September 1st, 2014, 11:13 am

***Updated for 2020***

The below is a Regimen, which is an approach that has been tested to address an element of lawn care. Mixing this regimen with other regimens (seeding, irrigation, fungal disease control, pre-emergents, etc) is up to the lawn owner.


Fall Nitrogen fertilization is probably one of the single most important aspects of the entire lawn calendar, and casual lawn owners get it wrong more than any other item in the year. There is more incorrect material out there on the Internet that gets repeated again and again, and it gets quoted as gospel just through sheer repetition.

This thread will try to gather up some practices that work well together. After discussion and clarifications, it will be permanently posted in the Articles area for reference.

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 very large bodies of water or in the Transition Zone (longer time between first-frost and growth stoppage), or in higher-elevation areas (shorter time between first-frost and growth stoppage). A good calculator for first-frost dates is at the bottom of this first posting.

While this thread will recommend that you do a little research go get rough dates to determine how to apply it to your area, it is critically important to realize that every year is different and that reliance upon a calendar is a huge mistake. The best use for a calendar is in the compost heap -- there it can provide value as organic matter. It can rest there comfortably next to your notes about air temperatures and soil temperatures. The only things that you need to rely upon are some facts about what is typical for your area, and your eyeballs.

If you have managed to keep your lawn out of dormancy in late Summer, just before Labor Day (in my area, just north of NYC), grass goes through a shedding period -- this is the grass realizing that the high sunlight period is over and done with. It typically aligns with a week or two after the evening temperatures begin to decline. It looks like there is a browning of a percentage of all of the grass blades. It may be mistaken for a mild fungal disease, but it is very even in its distribution across the lawn. Typically, it is less-pronounced in shadier areas. This is the grass changing from its high light pattern to the pattern of Early Fall. I use this signal as my sign that it is time to begin lowering the mower deck toward Fall heights, which are lower. This may actually (very temporarily) make the shedding brown blades appear a little more pronounced, but it is needed to get the Fall regimens underway without sudden dramatic height changes.

Once the shedding period is over, the lawn begins to really perk up. If you have weeds, you will notice that they really start to show up again too. Under the grass canopy, fall-germinating weed seeds and grass seeds begin to germinate, but will be too small to see for a while. Poa Annua begins to germinate too, but you won't see it.

This is the time to begin the Fall Nitrogen applications.

Some folks say that this period is when 2/3 of all Nitrogen should be applied, but it's a little more complex than that. There are actually three different periods in Fall, and applying Nitrogen during them is different for each one. They are:

Early Fall
Where I live, this period starts around Labor Day. I like to apply a mild "wake up" dose of Milorganite a couple of weeks before Labor Day, to gently move the grass from any dormancy to active growth - I don't like synthetics for this job. Where you are, it is probably the 6-8 weeks prior to average first frost date, but in any year it varies, and the "perking up" is the sign to watch for. If you are on a soil remediation plan, stay with it and make sure that you're getting a full complement of Nitrogen down with any other nutrients specified. If you're not on a soil remediation plan, make a decision about how you're going to add Nitrogen: (1) standard or (2) aggressively. If you are going to do a Standard regimen, begin applying a slow-release (coated) Urea or Ammonium Sulfate fertilizer, or Milorganite. Do it so that you deliver about a pound of Nitrogen per 1000 sq ft, per month. The idea is to have the last of the time-release Nitrogen peter out right around the time of average first-frost.

For those that want to really be aggressive about Fall Nitrogen fertilization (recommended except for Renovations), and don't mind the extra application work, pure (fast-release) Urea or Ammonium Sulfate fertilizer can be applied weekly to deliver about 0.5 lbs/K of Nitrogen. For Urea, this is right about 1 lb/K of 46-0-0 Urea. The techniques are "borrowed" from sports field techniques to keep football and soccer fields healthy and dense under heavy usage. This is not the full amount of Urea that could be applied at once, but increases the safety factor for homeowners by doing smaller, more-frequent applications instead of a large single application, where a mistake can hurt the lawn. Make sure to water in any fast-release fertilizer applications - don't rely on "predicted" rainfall. Do not do very aggressive weekly Nitrogen techniques with coated slow-release fertilizers - it is very difficult to figure out how much Nitrogen is still available from previous applications. I'll repeat it once more - don't use coated or extended release fertilizers for the "Aggressive" regimen.

You will not find fast-release Urea and/or AS fertilizers at big-box stores - don't waste your time trying. The best sources are farm-supply stores and places where landscapers and golf courses shop. Urea and AS will not come with homeowner instructions - it will be in very plain unbranded paper or plastic bags. The "aggressive" program is not 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. Done properly on a lawn that has no other growth-limiting nutrient shortages, you will see a turf that becomes denser and darker. Yes, you will be mowing more.

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 to let the grass slow down the top-growth naturally -- continued Urea or AS treatments will force continued growth. I call the period of natural slowdown and stoppage of growth "The Pause". During this period, no Nitrogen applications should be made. The grass will follow its natural progression to stoppage of growth. Continuing your Nitrogen apps through "The Pause" period may cause tender new growth to occur, which may increase the likelihood of winter damage.

Late-Fall/Winterizing
Continue the mowing of the lawn during The Pause, and watch for signs of slowdown/stoppage of growth. The day will come when you mow the lawn and nothing gets cut. When that happens, stoppage has occurred. DO NOT PULL THE TRIGGER EARLY ON THIS STEP. There is a period of about three weeks after top-growth ceases where the roots continue to grow and store nutrients. This is the time to apply the fast-release Urea as a Winterizer. The lawn will store the Nitrogen in the roots for use at Spring Green-Up. Done properly, you may not need Spring fertilizer until almost Memorial Day next Spring, and green-up will be earlier.

Apply the Winterizer as fast-release Urea or AS, all at once. The application should be 1 lb/K of Nitrogen which is a tiny bit more than 2 lbs/K of 46-0-0 Urea. Burning is less-likely as top-growth will have ceased.


A few notes:

(1) If you prefer organic sources, you can use them successfully for Early Fall treatments, but they can't be used as Winterizers as the microherd goes to sleep around the same time as grass top-growth stoppage.

(2) Don't follow air temperatures or soil temperatures to determine Winterizer dates. If the soil temperature says the time is right, but the grass is still actively growing, you are still in "The Pause". Applying Winterizer too early will cause top-growth to continue, which can definitely cause Winter Kill and damage to the grass.

(3) I don't recommend the use of a fertilizer containing Potassium after first-frost. There is at least one study that indicates that this can increase Snow Mold occurrence.

(4) Grass heights should continue to be shortened as the Fall season goes on. Do it steadily, not all at once.

(5) Many commercial fertilizers continue to be sold as "Winterizer" that follow the "science" of 15-20 years ago, which has been disproven. They do it because many people will ask for it and buy it, and they are happy to sell their products. Don't fall for "if a big company sells it, it must be right".

(6) Using slow-release fertilizers for Winterizer is not a good idea. The short window of root-only growth may not get all the benefit and nutrients from the fertilizer before root-growth stops.

(7) The use of the Aggressive N programs on lawns with PGR's is not yet tested, and I do not know if they can handle the same amount of Nitrogen in a compressed period. If you're doing that on a PGR-treated lawn, keep your eyes open.

(8) The grasses of newly-seeded renovations should not be treated with the Aggressive program until you are certain that the Spout-and-Pout stage is fully completed and the lawn is at least 30 days old. Failure to follow this point may lead to forced top-growth when the grass should be pausing to accomplish root-growth.

(9) If you are using an annual Humic Acid regimen, be aware that the Humic Acid may hold Nitrogen in the upper regions of the soil. While this is good, it may mean that the frequency of Urea can/should be adjusted (downward) a bit. Keep your eyes open for any signs of overapplication, and adjust your application rate as needed.

So, that's it -- time to watch the grass for signs and get to work. I'll make adjustments and clarifications within this first posting as questions are answered.

Average First-Frost Date by Zip Code

Advice to folks doing this for 2+ years: chart how long it is between Average First Frost and growth stoppage, and do that for a few years before using an average of the values to replace my best estimate for you (3-4 weeks). This will evolve the program from Andy's best guess to YOUR best information.
Last edited by andy10917 on August 15th, 2016, 4:58 pm, edited 2 times in total.

User avatar
SW315
Posts: 643
Joined: April 10th, 2011, 2:37 pm
Location: Indianapolis, Indiana
Grass Type: Front Yard: Bewitched, America and Beyond United Seed Super Turf 1 overseed 9/2017 / Back yard: TTTF Mutt
Lawn Size: Not Specified
Level: Not Specified

Re: Fall Nitrogen Regimens

Post by SW315 » September 1st, 2014, 11:45 am

Great thread. Thanks for posting


Sent from my iOS device using the Yard Help App

User avatar
HoosierLawnGnome
Posts: 9587
Joined: May 22nd, 2013, 5:59 pm
Location: Indianapolis, Indiana
Grass Type: Blueberry KBG
Lawn Size: 1 acre-2 acre
Level: Advanced

Re: Fall Nitrogen Regimens

Post by HoosierLawnGnome » September 1st, 2014, 12:17 pm

What is the guideline for incorporating Milorganite and it's equivalents into the aggressive regimen?

On a high pH soil like mine I need it for iron.

My current plan is to use Milorganite in conjunction with urea by decreasing the amount of urea base on the WSN % in the milorganite.

I kind of ignore the WIN.

Oh and beware of fungi that love high fertility environments!

[ Post made via Android ] Image

Billybob
Posts: 1484
Joined: May 5th, 2012, 11:29 pm
Location: Central NJ
Grass Type: TTTF
Lawn Size: Not Specified
Level: Not Specified

Re: Fall Nitrogen Regimens

Post by Billybob » September 1st, 2014, 12:20 pm

Very helpful... Glad it's going into Articles. Good to reference year to year

[ Post made via iPhone ] Image

User avatar
andy10917
Posts: 29116
Joined: February 23rd, 2009, 10:48 pm
Location: NY (Lower Hudson Valley)
Grass Type: Emblem KBG (Front); Blueberry KBG Monostand (Back)
Lawn Size: 1 acre-2 acre
Level: Advanced

Re: Fall Nitrogen Regimens

Post by andy10917 » September 1st, 2014, 12:29 pm

What is the guideline for incorporating Milorganite and it's equivalents into the aggressive regimen?
I will skip a week of the Urea apps whenever I decide to use Vitamin M instead. I may go a little lighter on the Urea the following week, but I haven't seen bad effects if I go back to the Urea at 1 lb/K (0.5 N). YMMV, keep your eyes open when doing any aggressive technique - including this one.

BTW, you triggered a thought that I meant to put into the original post -- I have no idea or experience with this technique on lawns that are using PGR's. I'm adding a note to it.


fun4me2
Posts: 533
Joined: May 19th, 2013, 9:46 am
Location: Western MA (upper pioneer valley) ZONE 6A
Grass Type: Northern Mix
Lawn Size: 3000-5000
Level: Some Experience

Re: Fall Nitrogen Regimens

Post by fun4me2 » September 1st, 2014, 12:39 pm

What about those who are using synthetic fertilizer for fall?
So far I dropped 8 bags of Milo 36lb for 5,000 sq ft.
Last drop was about 3 weeks ago.
I have a bag of Scotts Turf builder 32-0-4, is it ok to drop it now at bag rate?

User avatar
rydaddy
Posts: 423
Joined: June 10th, 2013, 6:43 pm
Location: Kalamazoo, MI
Grass Type: KBG
Lawn Size: 20000-1 acre
Level: Experienced

Re: Fall Nitrogen Regimens

Post by rydaddy » September 1st, 2014, 12:44 pm

Holy cr@p Andy. Thanks for all the effort you put into that!


Sent from my iOS device using the Yard Help App

SNJlawn
Posts: 276
Joined: November 27th, 2011, 10:24 am
Location: South Jersey
Grass Type: KBG
Lawn Size: Not Specified
Level: Not Specified

Re: Fall Nitrogen Regimens

Post by SNJlawn » September 1st, 2014, 12:47 pm

Is the aggressive plan strictly a kbg thing or can it be done on tttf, prg, or northern mix lawns?

[ Post made via Android ] Image

User avatar
andy10917
Posts: 29116
Joined: February 23rd, 2009, 10:48 pm
Location: NY (Lower Hudson Valley)
Grass Type: Emblem KBG (Front); Blueberry KBG Monostand (Back)
Lawn Size: 1 acre-2 acre
Level: Advanced

Re: Fall Nitrogen Regimens

Post by andy10917 » September 1st, 2014, 12:48 pm

What about those who are using synthetic fertilizer for fall?
So far I dropped 8 bags of Milo 36lb for 5,000 sq ft.
Last drop was about 3 weeks ago.
I have a bag of Scotts Turf builder 32-0-4, is it ok to drop it now at bag rate?
Urea is interesting -- today it is almost completely derived synthetically. Even though it exists in nature, I consider it "synthetic" as it bypasses the Nitrogen Cycle that occurs with grains, Milorganite, etc.

The 32-0-4 is a good product for use as a high-Nitrogen source (although it is much more expensive than plain ol' Urea). As long as none of it is slow-release, it could be used at bag-rate in a Standard or Aggressive regimen. If it is slow-release, it is OK for a Standard approach only.

User avatar
likeasponge
Posts: 611
Joined: November 27th, 2010, 9:04 am
Location: Northern Idaho
Grass Type: Bewitched/prosperity
Lawn Size: 5000-10000
Level: Experienced

Re: Fall Nitrogen Regimens

Post by likeasponge » September 1st, 2014, 12:52 pm

andy10917 wrote: This thread will try to gather up some practices that work well together. After discussion and clarifications, it will be permanently posted in the Articles area for reference.

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. I call the period of natural slowdown and stoppage of growth "The Pause". During this period, no Nitrogen applications should be made. The grass will follow its natural progression to stoppage of growth.

Average First-Frost Date by Zip Code
I'm not sure how to say this with clarity.....

Some years, the difference between winter and spring is during the 3-4 weeks of "the pause" here in zone 7a (clt area). Some years you get growth stoppage and some years the growth wont stop. Watching what your grass is doing may be different than your neighbors.

Great article; thanks Andy

User avatar
andy10917
Posts: 29116
Joined: February 23rd, 2009, 10:48 pm
Location: NY (Lower Hudson Valley)
Grass Type: Emblem KBG (Front); Blueberry KBG Monostand (Back)
Lawn Size: 1 acre-2 acre
Level: Advanced

Re: Fall Nitrogen Regimens

Post by andy10917 » September 1st, 2014, 12:55 pm

Is the aggressive plan strictly a kbg thing or can it be done on tttf, prg, or northern mix lawns?
It can be done on KBG, TTTF, and PR. For NoMix lawns, I'd be a little less aggressive, especially if Fine Fescues or Hard Fescues are a larger part of the mix - they don't care for high fertility levels. I would not use the Aggressive technique on a northern Zoysia lawn -- Zoysia does not follow the same growth stoppage cycle as true Cool Season grasses.

SNJlawn
Posts: 276
Joined: November 27th, 2011, 10:24 am
Location: South Jersey
Grass Type: KBG
Lawn Size: Not Specified
Level: Not Specified

Re: Fall Nitrogen Regimens

Post by SNJlawn » September 1st, 2014, 12:56 pm

Sounds good. Thanks

[ Post made via Android ] Image

fun4me2
Posts: 533
Joined: May 19th, 2013, 9:46 am
Location: Western MA (upper pioneer valley) ZONE 6A
Grass Type: Northern Mix
Lawn Size: 3000-5000
Level: Some Experience

Re: Fall Nitrogen Regimens

Post by fun4me2 » September 1st, 2014, 1:01 pm

andy10917 wrote:
What about those who are using synthetic fertilizer for fall?
So far I dropped 8 bags of Milo 36lb for 5,000 sq ft.
Last drop was about 3 weeks ago.
I have a bag of Scotts Turf builder 32-0-4, is it ok to drop it now at bag rate?
Urea is interesting -- today it is almost completely derived synthetically. Even though it exists in nature, I consider it "synthetic" as it bypasses the Nitrogen Cycle that occurs with grains, Milorganite, etc.

The 32-0-4 is a good product for use as a high-Nitrogen source (although it is much more expensive than plain ol' Urea). As long as none of it is slow-release, it could be used at bag-rate in a Standard or Aggressive regimen. If it is slow-release, it is OK for a Standard approach only.
Thanks Andy.
Reading the label there is some slow-release product. So Standard approach it will be. Sounds like that will be it for me this season.
Need to wait for rain however.
Lately, it's been going all around my neck of the woods. :banghead:

User avatar
andy10917
Posts: 29116
Joined: February 23rd, 2009, 10:48 pm
Location: NY (Lower Hudson Valley)
Grass Type: Emblem KBG (Front); Blueberry KBG Monostand (Back)
Lawn Size: 1 acre-2 acre
Level: Advanced

Re: Fall Nitrogen Regimens

Post by andy10917 » September 1st, 2014, 1:06 pm

Some years, the difference between winter and spring is during the 3-4 weeks of "the pause" here in zone 7a (clt area). Some years you get growth stoppage and some years the growth wont stop. Watching what your grass is doing may be different than your neighbors.
This is why I describe visual signs and cues to use in your area, instead of hard dates. In Presque Isle, Maine there will likely be frost three weeks from now -- they get 364 days of winter and a day of crappy skiing. In deep Transitional areas, there may be little or no growth stoppage. Adjust the techniques based on your climate and observations. If I had a 3-week "winter", I'd skip the Winterizer step, personally -- I'd go Early Fall, The Pause, and then pick up things when stable growth resumed.

Pway
Posts: 735
Joined: May 29th, 2014, 5:42 pm
Location: Piscataway NJ
Grass Type: Northern Mix
Lawn Size: 20000-1 acre
Level: Some Experience

Re: Fall Nitrogen Regimens

Post by Pway » September 1st, 2014, 1:11 pm

Just super, many thanks!

User avatar
HoosierLawnGnome
Posts: 9587
Joined: May 22nd, 2013, 5:59 pm
Location: Indianapolis, Indiana
Grass Type: Blueberry KBG
Lawn Size: 1 acre-2 acre
Level: Advanced

Re: Fall Nitrogen Regimens

Post by HoosierLawnGnome » September 1st, 2014, 1:35 pm

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.

This is my first year using so I don't know whether I should decrease feeding or not.

At the moment I am not applying it, but I fully intend to resume after an experiment and my sprinkler installation turf damage repairs itself.

[ Post made via Android ] Image

User avatar
andy10917
Posts: 29116
Joined: February 23rd, 2009, 10:48 pm
Location: NY (Lower Hudson Valley)
Grass Type: Emblem KBG (Front); Blueberry KBG Monostand (Back)
Lawn Size: 1 acre-2 acre
Level: Advanced

Re: Fall Nitrogen Regimens

Post by andy10917 » September 1st, 2014, 1:46 pm

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...

User avatar
HoosierLawnGnome
Posts: 9587
Joined: May 22nd, 2013, 5:59 pm
Location: Indianapolis, Indiana
Grass Type: Blueberry KBG
Lawn Size: 1 acre-2 acre
Level: Advanced

Re: Fall Nitrogen Regimens

Post by HoosierLawnGnome » September 1st, 2014, 3:21 pm

Well, I got that information from a guy who spent years managing golf course turf, but I also haven't had the opportunity to ask him if they reduced fertilization etc. Granted, it's a golf course, so I doubt they pump the turf up to the levels we do here.

User avatar
HoosierLawnGnome
Posts: 9587
Joined: May 22nd, 2013, 5:59 pm
Location: Indianapolis, Indiana
Grass Type: Blueberry KBG
Lawn Size: 1 acre-2 acre
Level: Advanced

Re: Fall Nitrogen Regimens

Post by HoosierLawnGnome » September 1st, 2014, 3:31 pm

LOL - sorry for the double post. I was rereading some stuff on Tenacity and poa annua and came across the MSU article on sports field management for KBG, which is basically the aggressive program above.

http://sturf.lib.msu.edu/article/2009apr58.pdf

virginiagal
Posts: 638
Joined: January 18th, 2014, 4:26 pm
Location: Richmond VA
Grass Type: tall fescue
Lawn Size: Not Specified
Level: Not Specified

Re: Fall Nitrogen Regimens

Post by virginiagal » September 1st, 2014, 3:40 pm

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.

[ Post made via Android ] Image

Post Reply

Who is online

Users browsing this forum: No registered users and 2 guests