# Why you should never EVER cut more than 1/3



## BXMurphy (Aug 5, 2017)

You have heard the experts say that you should never, EVER, cut more than 1/3 off the top of your lawn. Is it an old wive's tale? Is it "common knowledge"? As it turns out, the very structure of a blade of grass reveals the secret! Here is what I mean...

Most of the photosynthetic process of a blade of grass takes place in the middle third of the blade. The bottom third tends to be older and stemmier. The top third is younger, less developed, and tapers to a point. This taper cuts down on surface area.

Ah, but that middle third... it is the widest part of the whole blade! It is the most completely developed... It has everything it needs, and more, to be the powerhouse photosynthetic factory for the entire blade. Most of the life-giving effort of a blade of grass takes place in the middle 1/3.

When you let your grass grow too long and then mow it short in order to get ahead of it, you are cutting into that middle one-third. You are cutting into (or maybe cutting off) the life-giving force of that whole blade of grass.

Please be gentle with your grass. Mow it more frequently if you have to. The grass will thank you and your lawn will be the envy of the neighborhood.


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## crussell (Mar 12, 2018)

What is the rule of thumb for lowering, while following the 1/3rd rule? If I mow 1/3rd of my blade, how long do you wait to cut into the next 1/3rd?


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## g-man (Jun 15, 2017)

I call it the 1/3 guideline. We all have broken it from time to time.

To lower your hoc, go in steps. If you at normally at 3in, now on you normal now day at 3. Then 2-3 days later now at 2.75. Keep mowing there until you get the color back, then drop to 2.5 and wait. Don't do this in the middle of summer.


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## pennstater2005 (Jul 17, 2017)

Gotta say this is one of the things I struggle with the most. I almost always take more than a 1/3rd. How much more I don't know. I need this.....

https://m.youtube.com/watch?v=KE7O3dK07nQ


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## GrassFarmer (Sep 21, 2017)

No stripes not acceptable.


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## g-man (Jun 15, 2017)

I have a neighbor with one of these. 1) I dont like the cut. It looks like a string trimmer all over the lawn, 2) it cant handle long/wet grass, it just bends it down instead of cutting and 3) the mower leaves a wide area of uncut grass along the green cord, it either needs a real mower or a string trimmer. 4) it is a random pattern.


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## dfw_pilot (Jan 28, 2017)

pennstater2005 said:


> Gotta say this is one of the things I struggle with the most.


Jump in on the next PGR group buy.


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## pennstater2005 (Jul 17, 2017)

g-man said:


> I have a neighbor with one of these. 1) I dont like the cut. It looks like a string trimmer all over the lawn, 2) it cant handle long/wet grass, it just bends it down instead of cutting and 3) the mower leaves a wide area of uncut grass along the green cord, it either needs a real mower or a string trimmer. 4) it is a random pattern.


They would definitely need to improve upon it before I would consider buying. The random pattern is weird.


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## stotea (Jul 31, 2017)

Most of the time, I literally measure my grass height with a tape measure to make sure I'm not gonna cut off more than a third, haha.


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## BXMurphy (Aug 5, 2017)

stotea said:


> Most of the time, I literally measure my grass height with a tape measure to make sure I'm not gonna cut off more than a third, haha.


You are a sick, sick man! But don't worry, this is something that can be cured with a good beer and an amazing lawn.


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## MarkAguglia (Jul 13, 2017)

I cannot keep up with the 1/3 rule.... even before applying any fertilizer this spring, I'd have to mow every other day! I put down a tiny amount of starter fert this week and I can basically see the grass growing! Almost impossible for me in spring and fall.


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## Delmarva Keith (May 12, 2018)

Agreed, but often not possible. Right about now local tall fescue is growing about 1/2" per day. Let that go much more than a week and results are what you predict - a sickly yellowish tint for about two weeks. The turf does NOT like it.


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## BXMurphy (Aug 5, 2017)

That growth spurt in the spring is a killer. I can now appreciate the recommendations to not fertilize until Memorial Day. I used to think that was crazy talk until I tried keeping up with the one-third rule. Honestly, I have no idea how the guys with the big lawns do it. Quite remarkable.


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## g-man (Jun 15, 2017)

One word: PGR.


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## Sinclair (Jul 25, 2017)

BXMurphy said:


> That growth spurt in the spring is a killer. I can now appreciate the recommendations to not fertilize until Memorial Day. I used to think that was crazy talk until I tried keeping up with the one-third rule. Honestly, I have no idea how the guys with the big lawns do it. Quite remarkable.


I have a small front lawn that I love to mow, so I've got it really flying right now.

I haven't fertilized the back yet, as it's a pain to mow.


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## Butter (Nov 14, 2017)

Death, taxes and breaking the 1/3 rule!


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## BXMurphy (Aug 5, 2017)

MarkAguglia said:


> I cannot keep up with the 1/3 rule.... even before applying any fertilizer this spring, I'd have to mow every other day! I put down a tiny amount of starter fert this week and I can basically see the grass growing! Almost impossible for me in spring and fall.


Hmm... 4,000 SF and 32 years old. I'm guessing your constraint is time. Consider mowing half your lawn one day and the other half the next... or something like that...


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## MarkAguglia (Jul 13, 2017)

BXMurphy said:


> MarkAguglia said:
> 
> 
> > I cannot keep up with the 1/3 rule.... even before applying any fertilizer this spring, I'd have to mow every other day! I put down a tiny amount of starter fert this week and I can basically see the grass growing! Almost impossible for me in spring and fall.
> ...


Haha yes full time job, commute, and 2 dogs alone are enough of a time constraint.


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## DTCC_Turf (May 26, 2018)

http://www.turfnet.com/blog/4-dr-frank-rossi-frankly-speaking/

A lot of this discussion is golf course specific but does touch on the one third rule for tall fescue at lawn height.


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## probasestealer (Apr 19, 2018)

I was gone for 8 days, cut easily half the height of the lawn on Saturday with my mower at the tallest setting. The lawn had to be cut again today, the clippings were so thick I had to bag.
I don't think I did any harm breaking the 1/3 rule


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## social port (Jun 19, 2017)

probasestealer said:


> I was gone for 8 days, cut easily half the height of the lawn on Saturday with my mower at the tallest setting. The lawn had to be cut again today, the clippings were so thick I had to bag.
> I don't think I did any harm breaking the 1/3 rule


It seems that many of us have been in this position recently, including myself. I wish manufacturers would allow for higher HOCs (e.g. beyond 4.5) on mowers.

I had to bag as well (had to empty 8 times). I am expecting some yellowing, but I am confident that the color will recover quickly.
I think the key is that the 1/3 rule shouldn't be violated often, but once in a while won't break the lawn.


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## probasestealer (Apr 19, 2018)

social port said:


> probasestealer said:
> 
> 
> > I was gone for 8 days, cut easily half the height of the lawn on Saturday with my mower at the tallest setting. The lawn had to be cut again today, the clippings were so thick I had to bag.
> ...


You just don't want to cut off the"leaf"


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