# Environmental Conditions Courtesy of Extension



## BXMurphy (Aug 5, 2017)

There was some discussion on the cool season side about growing degree days and how it helps you with the best time to re-apply plant growth regulator (PGR). Many hobbyists are using Greenskeeper app to generate that data.

I groaned at that degree of complexity but was delighted when I learned that my county extension provided that info in one of their monthly newsletters:

http://ag.umass.edu/landscape/landscape-message-jun-7-2019

UMass rocks! (Of course.) Check with your own extension to see if they do something similar if you want this kind of control. I thought it was pretty neat.

Murph


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## Ware (Jan 28, 2017)

BXMurphy said:


> ...I groaned at that degree of complexity but was delighted when I learned that my county extension provided that info in one of their monthly newsletters...


Good info, but unfortunately monthly GDD reporting would not be much help to someone applying PGR. I track daily as I am approaching my reapplication interval.


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## BXMurphy (Aug 5, 2017)

Yep... my reapplication date is tomorrow but I'm only going by the Rule of Thumb suggestion of every three weeks. I understand that as the days get warmer, I should be switching to every two weeks, right?

This info will help my learning curve without having to learn and look at an app every day.

The way I look at it (and this is just for me), I will begin to get a feel for what Growing Degee Days mean for my lawn (plus everything else I'm doing with flowers, veggies, and drip irrigation)... How the lawn looks, how the temps feel, and what effect the PGR has on all that without getting too crazy. For me, if it gets too over-the-top, it won't get done.

This is only year #2 for me. I learned about GDD just this year and want to learn more as time permits. Maybe others find themselves in the same boat. All this info can be a bit overwhelming.

I would encourage budding newbies to explore everything their extension offers - right down to GDD. It is mind-blowing all the LOCAL info that is available - and paid for with your tax dollars! 

Murph


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## g-man (Jun 15, 2017)

BXMurphy said:


> Yep... my reapplication date is tomorrow but I'm only going by the Rule of Thumb suggestion of every three weeks. I understand that as the days get warmer, I should be switching to every two weeks, right?


If the app says to reapply tomorrow, then that's it. There is no rule of thumb of 3 weeks. As the days get warmer the application window will change, but the app keeps track of all that. The science behind gdd is very sound.


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## BXMurphy (Aug 5, 2017)

g-man said:


> BXMurphy said:
> 
> 
> > Yep... my reapplication date is tomorrow but I'm only going by the Rule of Thumb suggestion of every three weeks. I understand that as the days get warmer, I should be switching to every two weeks, right?
> ...


Hmph. Bummer. I thought I was doing something good for my lawn by applying PGR but it seems like it's just for Lawn Wizards who also use the app?

Disappointed. I wish I didn't buy this stupid stuff and spend all that time reading through all the threads here about the wonders of PGR.

I might suggest someone post a sticky or correct the threads so other newbies don't fall for this... Wizard Dust.

I _swear_ I read in The Lawn Forum that a good rule of thumb was every three weeks.

Arrggggh! I wish a Three Mule Team would run me over with a thimble of Borax. Why would the extension even bother posting useless information? I feel like a fool for pointing out this report.

My bad...

Murph


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## dfw_pilot (Jan 28, 2017)

BX, FWIW, I used a simple 21 day window for PGR without issue. You can make lawn care as simple or complex as you wish.

I can promise you though, that PGR isn't wizard dust, but a very helpful tool in the lawn care tool box.

Cheers!


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## BXMurphy (Aug 5, 2017)

dfw_pilot said:


> I can promise you though, that PGR isn't wizard dust, but a very helpful tool in the lawn care tool box.
> 
> Cheers!


That's what I thought, too. I just started using it and am seeing fantastic results on my 90 year-old Granny Lawn! I can't wait to kill it this fall and plant something worth the effort.

I would have never... NEVER!... come to this point without help from The Lawn Forum. You guys are the BEST! The absolute best.

I'm sure @ware and @g-man didn't mean it but when I posted what I thought was a solid contribution to the forum... Growing Degree Days delivered straight to my inbox to get the hang of it and prepare for the next step in my progression... their response was pretty heavy-handed. "Not be much help," said one. And, "that's it," said another.

Gosh, lighten up a little, guys! I'm struggling to keep up and value every nugget you share from your years of solid experience, trials, and errors. Thank you so much for taking time out of your day and sharing your passion.

It's not easy to do... writing... thinking... taking pictures and posting them... but, believe me when I tell you, it means so much to a guy like me.

I'll get there, eventually, I'm sure, but in the meantime, I'll grow a thicker skin and continue making mistakes and learning from them. Sometimes a 2x4 upside the head is what this thick-headed Irishman needs.

I don't feel so bad about my mulch thread anymore. 

Murph


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## Ware (Jan 28, 2017)

@BXMurphy, I'm sorry if you took it the wrong way, but I stand by what I said. If someone chooses to make their PGR applications on a set GDD interval, there is really no way to use a report in a monthly newsletter to time their applications. They would pass their GDD interval every time. A source that reported GDD data daily would be a different story.


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## BXMurphy (Aug 5, 2017)

Ware said:


> @BXMurphy, I'm sorry if you took it the wrong way, but I stand by what I said. If someone chooses to make their PGR applications on a set GDD interval, there is really no way to use a report in a monthly newsletter to time their applications. They would pass their GDD interval every time. A source that reported GDD data daily would be a different story.


Gotcha. No harm done. I understand what you mean now.

Can a monthly gdd report be useful for anything? I do a lawn, of course. I also grow some flower beds and a couple of small veggie gardens. I've been installing drip irrigation to put watering on auto-pilot.

I suppose a monthly report of past conditions is just about as helpful as a report on last month's temperatures. Not really much help except for satisfying curiosity, right?

Maybe it's useful for trouble-shooting. Like... why did all my pretty flowers die when I've been watering on the same schedule? 

Yeah, I guess you're right... Never mind...

All my best,
Murph


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## krusej23 (May 8, 2018)

The greenkeeper app is easy to setup and can be useful for more than just PGR applications. It's probably not much help to put pgr down on a lawn that you don't like and you are going to kill this fall unless you are just practicing the applications. I would say just setup greenkeeper and that will tell you exactly when to put the pgr down.

3 weeks is not something to go off of. For example, right now my pgr is lasting about 2 weeks to 2.5 weeks because of the heat we have going on right now.


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## Ware (Jan 28, 2017)

Also worth noting, the GDD formula is not difficult. It would be pretty easy to calculate/track your own GDD's in a spreadsheet - you just need the high and low temperature for your location each day. The base temp is a constant (e.g. 50°F).

Just remember there are no negative GDD's. If the formula yields a negative number, GDD = 0.


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## BXMurphy (Aug 5, 2017)

That's it? THAT'S IT?!? Are you kidding me?? 

Man, I read that whole thread about the Greenskeeper app maybe three weeks ago and came away more confused than convinced!

And in the end, all I have to do is add the maximum and minimum temperatures together, divide that by two, and subtract out some (arbitrary?) base number and I'm good to go?

Yeah, I remember... some guys subtracting out 0° C... others taking away 32° F... Others doing 50° F... then a lot of debate on how many GDD to go out...

If I remember correctly, people where spraying every 200 GGD or so...?

But that formula... that's it... THAT'S IT? Sheesh!

Good grief, man! I installed that app. I set up a "golf green." And then got tired of the ads or nagging to upgrade... screwing around trying to find GDD out of all the different options... and finally said...

"You know what? I'll just put a reminder in my calendar. If every third weekend is close enough for government work; it's close enough for this stupid grass."

Ware, hold the window for me, will ya? I'm coming in off the ledge...

Murph


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## BXMurphy (Aug 5, 2017)

Well... will you look at that... just look at it...

The county report I just posted is using 50° F for a baseline...

Will you look at that... Saints be praised!

And now I'm thinking... all I have to do is look at my grass to find optimum GDD length. Discover when my grass rebounds and reapply 1.5 weeks earlier than my NEXT anticipated rebound.

Easy-peasy, lemon squeezy!

Murph


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## Ware (Jan 28, 2017)

Yes, that is how GDD are calculated. And by all means do what works best for you, but understand there are other reasons many of us choose to use the free GreenKeeper app.

GreenKeeper knows which base temperature to apply based on the grass species/location. It also automatically calculates the ideal PGR GDD re-application interval based on the PGR selected, application rate, grass species, and HOC. All of these factors influence the longevity of a PGR application. It is a great tool for tracking applications of other products as well.


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## krusej23 (May 8, 2018)

I love the greenkeeper app because it estimates when I should apply again so I can plan ahead a little.


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## Ware (Jan 28, 2017)

krusej23 said:


> ...3 weeks is not something to go off of. For example, right now my pgr is lasting about 2 weeks to 2.5 weeks because of the heat we have going on right now.





krusej23 said:


> I love the greenkeeper app because it estimates when I should apply again so I can plan ahead a little.


Agree. 21 day application intervals will no doubt suppress growth, but I believe the GDD approach helps maximize suppression. The lifespan of my current PGR app is forecasted to be 15 days.


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## BXMurphy (Aug 5, 2017)

Hmph. 15 days... will you reapply in 10 days?

I'm going to have to look at that app again.

What else can you do with it? Will it do enviro-transpirational calculations? THAT looks complicated...

What else can you do with GDD?

Thank you, gents...
Murph


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## BXMurphy (Aug 5, 2017)

krusej23 said:


> I love the greenkeeper app because it estimates when I should apply again so I can plan ahead a little.


Yes... GreenKeeper App. No "s." It's a web-based situation. Not in the app store. Mobile-friendly.

https://www.greenkeeperapp.com

Lemme tackle this again...

Murph


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## krusej23 (May 8, 2018)

I also use it to track my other applications I put down. It's not much better than any other way of tracking that sort of stuff for a diyer but it's nice to have it in one place. I'm kind of ADD sometimes so I like to put my fertilizer, FAS, or PGR applications in GreenKeeper first and then it prints out a nice report that I use when I go to put everything together in the sprayer or spreader. Here is an example of the nice report.


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## BXMurphy (Aug 5, 2017)

krusej23 said:


> I also use it to track my other applications I put down....


Yeah... I saw that... nice PDF and everything. I'm going to do the same thing because I'm like you. I'm so anal that I'm going to export the data at some point so it doesn't get lost or the site goes away.

That really is a nice little app. It has weather data in there and everything.

I'm glad I started this little thread. I've learned a lot over the past couple of days. I wish it didn't start out so badly... but, you know, what are you going to do? 

I'm going to have some other questions about this app. Is there a way to bookmark this thread so I don't lose track of it?

B


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## Stuofsci02 (Sep 9, 2018)

Click on your name at the top right and then select your profile an$ you can see the 5hreads you participated in..


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## Ware (Jan 28, 2017)

You can also click the wrench icon and select "Bookmark topic". Bookmarked topics can be managed within the User Control Panel.


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## BXMurphy (Aug 5, 2017)

Nice... PERFECT! Thanks, boys...

I noticed that Greenkeeper app changes the date of the next PGR application as we move through the season. I imagine that's because because the PGR lifespan changes with the temperature, right?

How cool is that?

Murph


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## Babaganoosh (Apr 21, 2019)

What app is this greenkeeper app? Is it greenkeeper or greenskeeper?

What's the app's symbol look like?


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## Ware (Jan 28, 2017)

Babaganoosh said:


> What app is this greenkeeper app? Is it greenkeeper or greenskeeper?
> 
> What's the app's symbol look like?


https://www.greenkeeperapp.com/

It is a web app, not an "app store" app.


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