Analyzed my historical data - fine-tuning the "pause" start date

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Green
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Analyzed my historical data - fine-tuning the "pause" start date

Post by Green » November 12th, 2019, 10:13 pm

A slightly more advanced topic, and still a work-in-progress...

A few years ago, I started noticing that the pause period (between average first frost and when growth stops) was consistently dragging on for about 6-8 weeks in my area. I noted this, and asked on here if grass really needed that much time to "go to sleep". Andy gave me an honest answer: It shouldn't. 4-6 weeks is generally sufficient. A possible reason for a longer pause that he gave was a local micro-climate due to a body of water nearby, etc., which moderates temps and keeps growth going longer. I don't have anything like that near me.

Ever since then, I've been thinking about this every year, but I had never amassed enough data points until now.

After analyzing my data for the 7 years from 2012-2018, I found that my average date at which growth stops in my yard is Dec. 1st. (That incidentally turned out pretty close to what I'd have expected, based on my experience and recollections of years past.)

My average first frost date is October 16th (based on some really good data I got last year from the CT Ag station for a test location very close to me).
So, my pauses over the years have been averaging 6.5 weeks. On Andy's recommendation based on his info pertaining to average, effective pause durations, I made a modification this year: I added one more week to my Fall Nitrogen fertilizing window. This effectively shortened my artificially-long pause by one week. Instead of pausing on or near October 17th, I now continue with Nitrogen if needed for an additional week, and start my pause around October 24th.

So far, so good. We'll see how it goes the rest of this year. Comments and questions are welcome.

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Re: Analyzed my historical data - fine-tuning the "pause" start date

Post by Green » November 12th, 2019, 11:05 pm

Note that this modification still leaves room for a 4.5-week pause, based upon the earliest date I observed growth to stop, ever (which was in 2014, when I winterized on November 23rd).

In case anyone is interested in my historical data and how I analyzed it here is a list of my area's optimal lawn Winterizing dates from previous years:


2018: Nov 24th

2017: Dec 5th (Nov 35th)

2016: Dec 6th (Nov 36th)

2015: Dec 21st (Nov 51st)

2014: Nov 23rd

2013: Nov 29th

2012: Nov 30th

First thing you notice is that the dates have a consistent cluster around the middle of the span between Nov 23rd and Dec 21st. It turns out, the data is robust enough that including versus not including the 2015 data point (an outlier due to a warm Fall) only changed the average yearly by 2-3 days.

Note: I changed all December dates to November dates to make the statistics easier. I then found the mean of the data set.

Avg. = Nov 32.5 (Dec. 3rd)
Avg. without 2015 = Nov. 29.5 (Nov. 3th)
Round to: Nov 30 to Dec 3rd - That's where the December 1st number came from.

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andy10917
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Re: Analyzed my historical data - fine-tuning the "pause" start date

Post by andy10917 » November 12th, 2019, 11:49 pm

Off-topic, but you are one of the "students" that a person that teaches (like me) keeps doing teaching for - you can find the nugget of learnings that teachers have made, internalize them, and then build them into your own observations and new ideas. I wish there were 100 people that could do that on the site. Keep your eyes open (the above posting says you do) and find the next level.

Just so that doesn't go to your head, you made an error on the next-to-last line -- it should say "Nov 30th" :no:

Green
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Re: Analyzed my historical data - fine-tuning the "pause" start date

Post by Green » November 13th, 2019, 7:58 pm

Andy: Thanks. That's what learning is...collecting ideas, asking questions, observing, trying things, and seeing what happens. Then, figuring out why, and refining.

Keep teaching.

I've been doing this long enough to know that if the overall weather patterns keep up this year, the result will be similar to a normal year for date of Winterizing...regardless of a few cold days/nights. I'm still betting on the last week of Nov. to the first week of Dec.

One thing that's interesting, is that the grass seems to have a peak around the average first frost date. By 4 weeks later, you can visually see a big difference. The trick seems to be targeting the last regular-season N application during the beginning of that declining phase as growth is about to start to slow, but not so far down the curve that the grass is trying to go to sleep and actually losing color naturally. I've tried over and over to see if leaf drop from trees is directly correlated to loss of color/top growth, and it doesn't seem to be that close a correlation. Leaf drop seems to vary more, if anything.

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Re: Analyzed my historical data - fine-tuning the "pause" start date

Post by Oldschool » November 14th, 2019, 9:32 am

Good Stuff Green...

I too find the fall regimen intriguing. I’m glad to see you have quite a few years of data showing the actual first frost as compared to historic first frost. I have seen the same here, but only have 3 years experience.

The fall regimen and winterizing is very important to me. I have a very short season with a first frost date of September 11th. So the regimen plus winterizing is half my season. My experience so far has my actual first frost falling two weeks beyond first frost historical date. I adjusted my regimen start date and also added an eighth application of regimen urea.

My challenge each year, specifically this year, is my growth stoppage. It hits somewhere in the last week of October. But so does the snow and bitter cold. If the snow hits late October, chances are I won’t see my grass again till April and miss the winterize application. In 2018, I made it by one day. This year an unexpected overnight storm hit on October 28th, grass had not completely stopped growing and I missed my winterize window. I’ll readjust my winterizing moving forward and pay much closer attention to weather, maybe drop winterizer even with very minimal growth.

Anyway, thanks for sharing your research. This is why I love ATY.

Lonnie


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Re: Analyzed my historical data - fine-tuning the "pause" start date

Post by Green » November 14th, 2019, 2:08 pm

Oldschool wrote:
November 14th, 2019, 9:32 am
Good Stuff Green...

I’m glad to see you have quite a few years of data showing the actual first frost as compared to historic first frost. I have seen the same here, but only have 3 years experience.
Thanks. Just to clarify, the data I tracked was when growth stopped. I define stopped as "Grass doesn't need to be cut after 10-14 days and soil is cold enough (but not yet frozen!) that it won't grow noticeably again until March". I probably do have some data of actual frost dates, but I don't know how useful that will be for anything.
Oldschool wrote:
November 14th, 2019, 9:32 am

My challenge each year, specifically this year, is my growth stoppage. It hits somewhere in the last week of October. But so does the snow and bitter cold. If the snow hits late October, chances are I won’t see my grass again till April and miss the winterize application.
And that's what I was keeping records of. I think it's a little easier here, though...snow doesn't tend to stick around long until the middle of Winter. Even then, it tends to melt, and the grass will eventually show if we don't keep getting more snow to replace what gets lost. Last November (about this time) we got 10 inches. I think it was gone in 7-10 days. I winterized no problem after it (not to mention continued mowing and cleaning up the leaves that were under the snow). I could see how it would be tougher if the first snow means you're going to be buried until April.

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Re: Analyzed my historical data - fine-tuning the "pause" start date

Post by Oldschool » November 14th, 2019, 5:31 pm

Green,

I knew you were talking about growth stoppage, just misquoted myself.

I’m still getting used to my weather. Been here three years and it’s a challenge to figure it’s tendencies. I ask a lot of questions to the old timers and the native Montanans. Most have said any snowfall after November 15th will stick, which is true. But two years in a row, late October snow has also stuck. I’m also between two large mountain ranges and things change rapidly and unexpectedly.

Half the fun is trying to figure out what Mother Nature is planning on doing year to year.

Thanks again for your research.

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Re: Analyzed my historical data - fine-tuning the "pause" start date

Post by Green » November 14th, 2019, 10:08 pm

So, it looks like this year is going to be another outlier, but in the opposite direction and same magnitude as 2015. I noticed today that growth has already stopped in my upper back lawn, which is always the first area to stop and last to start up in Spring (because it gets direct cold air, being up on a hill). Once I noticed growth had stopped, I pulled out the thermometer to make certain the ground wasn't actually frozen. Well, there are a couple of odd pockets that appear very close to frozen, but most of it was around 35.

I then inspected the rest of the lawn areas. The lower back (second area to stop normally) appears to be in the process of stopping...it's a solid green-gray color.

I then mowed the side front (a warmer area and normally one of the last to stop growing), and got very little clippings. The front is also starting to have a grayish color, and temps are right around 40.

So, it looks like I'll be winterizing the upper back before the next rain next week...a record-early winterization date. And the other areas wont be far behind.

The leaves definitely dropped mostly already, so maybe there's some correlation between trees and grass going dormant.

Did I give myself enough time to pause? I want to say yes, it seems to have been about 4 weeks.

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Re: Analyzed my historical data - fine-tuning the "pause" start date

Post by andy10917 » November 14th, 2019, 10:29 pm

It's tough to get it perfectly, and I've learned not to try. I'm conservative in this area, and would rather miss a 0.5 lb/K app than look at Spring grass with Winter damage. I was right on time for the Pause-to-Winterizer length this year.

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Re: Analyzed my historical data - fine-tuning the "pause" start date

Post by Green » November 14th, 2019, 10:35 pm

andy10917 wrote:
November 14th, 2019, 10:29 pm
It's tough to get it perfectly, and I've learned not to try. I'm conservative in this area, and would rather miss a 0.5 lb/K app than look at Spring grass with Winter damage. I was right on time for the Pause-to-Winterizer length this year.
Did your Winterizer drop happen yet? Seems to me your area is usually a bit ahead of ours. Whenever I go to my cousin's house in Sullivan County (even colder than where you are?) it's often colder than here.

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Re: Analyzed my historical data - fine-tuning the "pause" start date

Post by andy10917 » November 15th, 2019, 12:05 am

Front Yard ("Emblem") yes, Back Yard ("Blueberry") no.

Green
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Re: Analyzed my historical data - fine-tuning the "pause" start date

Post by Green » November 25th, 2019, 11:22 pm

Update: so far, so good. Most areas are still in the pause at this time.

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