1/3rd rule

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jfoege
Posts: 105
Joined: July 12th, 2016, 2:39 pm
Location: New Haven County, CT
Grass Type: Northern Mix
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1/3rd rule

Post by jfoege » September 11th, 2017, 12:56 pm

Hey all,

I understand the 1/3rd rule in mowing and why it's used.

E.g. Your height of cut is set to 2", meaning you mow at 3" back down to 2" and you've only removed 1/3rd of the blade.

Here is where my confusion comes in:

A lot of grass types can be a bit floppy on top. So, if I put the ruler in and measure the average turf height including flopped over tops, I might get 3", say. But, if I unfurl and measure the longest blades held straight, then I might see 4"...

I've tried to ask this before, but no one seemed to have a definitive answer. Can anyone clear this up for me?

Thanks in advance!

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MorpheusPA
Posts: 18129
Joined: March 5th, 2009, 7:32 pm
Location: Zone 6 (Eastern PA)
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Re: 1/3rd rule

Post by MorpheusPA » September 11th, 2017, 2:58 pm

Since you're going to cut off that unfurled part with the rest of it (the mower has suction), count it. So if your unfurled length is 4" while the flopped-over length is 3", count the length as 4".

jfoege
Posts: 105
Joined: July 12th, 2016, 2:39 pm
Location: New Haven County, CT
Grass Type: Northern Mix
Lawn Size: Not Specified
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Re: 1/3rd rule

Post by jfoege » September 11th, 2017, 3:05 pm

Got it. Thanks!

jfoege
Posts: 105
Joined: July 12th, 2016, 2:39 pm
Location: New Haven County, CT
Grass Type: Northern Mix
Lawn Size: Not Specified
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Re: 1/3rd rule

Post by jfoege » September 12th, 2017, 2:31 pm

Hey MorpheusPA, I checked out your blog and I love the flower gardens. I see you love the marigolds and zinnias just like I do! Your flowers look great.

I was wondering if you could give me some advice? Just about every book I've read on lawns tells me I should aim for a height of cut of 2.5" on a PR/FF/KBG northern mix. My new reno project is coming in nicely and it looks like I'm getting broad germination on the KBG here at day 16. My only problem with waiting until the grass is at 3.5" and change to cut is that I'm worried about the PR shading out the newly gwrminated FF and KBG.

On the other hand, keeping it tall shades out newly germinating weeds and shades the soil, reducing my watering burden.

Do you all mow low here during establishment phase and switch to a taller HOC later on? Or is keeping it between 2.5 and 3.75 inches tall even as a brand new lawn with little KBG sprouts hiding underneath the PR just fine?

Am I worrying too much? I like the way lawns look at a 1
.5-2" HOC personally, but we wont be irrigating here except in July and August. And even then only enough to keep it out of dormancy.

Thanks in advance.

John

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MorpheusPA
Posts: 18129
Joined: March 5th, 2009, 7:32 pm
Location: Zone 6 (Eastern PA)
Grass Type: Elite KBG
Lawn Size: 10000-20000
Level: Advanced

Re: 1/3rd rule

Post by MorpheusPA » September 12th, 2017, 6:30 pm

Thanks! Yeah, I do love me some zinnia, marigold, and dahlia!

Really, it's dealer's choice on the length. It'll shade out weeds best, require less water, and have much deeper roots the longer you let it go (when established). But if you prefer it shorter, then simply accept that you'll have to weed more, water more, and it won't be as drought tolerant.

I mow at 3" to 3.5" all year--I prefer that. My mother mows at 2-2.5" spring and fall, and 3"-4" during the summer. Both methods work great. Shorter lawns tend to burn out more easily, but...

During establishment, the first mow is done as soon as you can reasonably do it to encourage tillering. For me, that was about 2" or so (my mower is a robot, though). Then adjust up to the height you want.


jfoege
Posts: 105
Joined: July 12th, 2016, 2:39 pm
Location: New Haven County, CT
Grass Type: Northern Mix
Lawn Size: Not Specified
Level: Not Specified

Re: 1/3rd rule

Post by jfoege » September 12th, 2017, 6:56 pm

Funny...I'm growing marigolds, zinnias and dahlias, too! :lol:

I'll take some pictures of my dahlias for you soon!

jfoege
Posts: 105
Joined: July 12th, 2016, 2:39 pm
Location: New Haven County, CT
Grass Type: Northern Mix
Lawn Size: Not Specified
Level: Not Specified

Re: 1/3rd rule

Post by jfoege » September 14th, 2017, 11:31 pm

Hey MorpheusPA, I added some pics of the latest blooms to open to my 'Dahlias 2017' album on my Google drive folder:

https://drive.google.com/open?id=0Bw2KO ... F9vVnpVOEE

If you click the above link, you'll be able to see all of the images. Obviously, the ones named IMG-20170914xxx are the latest ones. You can arrange in ascending or descending order to see oldest first or last etc.

In a week or two almost all of them should be open (I got them in the ground about 3 weeks too late, and they aren't in a full sun location - hence the lateness)! I'm excited, though! This is my first year growing dahlias, and I just got me some el' cheapo Walmart tubers. So far, I'm really happy. Dahlias make awesome cut flowers for inside the house, too, I'm finding!

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