In my opinion, one of the reasons many so called ‘experts’ recommend a three inch cut for rotary lawn mowers is that they know it is NOT really a three inch cut. The reality is that the length of the grass blade left after mowing with a rotary lawn mower set to cut at three inches will always be much closer to two inches…read more.
What is the best HOC for the grass plant? If you look around the internet you may find that three inches seems to be a favorite recommendation. Why? There are many reasons for recommending a three inch cutting height, especially when using a rotary lawn mower. Interestingly, three inches is not the best HOC for the grass plant for many agronomic reasons.
What is the best height of cut for the grass on your lawn? There is no perfect or exact answer to this question so let’s discuss some of the variables that will impact this decision and why longer is often not better when mowing your yard. The very first thing to consider is what type of grass you have. This will be directly influenced by where in the country you live. If you live in the south or the west, you probably will have what we refer to as warm season grass, most typically a Bermuda grass variety, although there are many non Bermuda warm season grasses as well. If you live in the north down through the heart of the country or the mid-Atlantic, you probably have cool season grass, most likely Kentucky bluegrass, perennial ryegrass or a blend, although others exist here as well. The growth habit and physiology of these two types of grasses differ dramatically and we will discuss the differences elsewhere, but for now the important thing to remember is that warm season grass can tolerate and actually thrive at a very short mowing height, while cool season grasses generally prefer to be mowed slightly higher. What is not true is that either likes to be kept at an excessively long length and excessively long can legitimately be described as anything above three inches and shorter for warm season grass. Grass plants develop chlorophyll, the property that gives them their green color and nourishes them through a process called photosynthesis. This process is encouraged by sunlight. That is one of the reasons you have such a hard time growing grass under those large shade trees in your yard, no sun. Three inch grass blades and longer only serve to shade themselves, like when we wear a hat and this shade inhibits photosynthesis. At two inches, you have 33% less shade and a better developed leaf blade…
I am a big fan of your site. I’ve been reading it personally for a while now. I like that it’s simply designed and lawn focused in an ecologically sound way.
I especially loved the way you feature those tremendously cool antique lawn mowers. You really are doing a great job educating people about lawns, equipment and correct techniques!
I’ve been meaning to get in touch with you. I was quite interested to come across your article (Height of Cut Part 2) on cutting lawns to correct heights; I like the way you detail the information. There are far too many incorrect generalizations being made in the name of green lawn care these days.
My company has spent years developing and now promoting a fully enviro-friendly, low maintenance lawn alternative called Eco-Lawn. A proprietary blend of 7 fine fescues, Eco-Lawn is a potentially perfect lawn for fans of ecomowers.. Fine fescues grow naturally in the woods and in open meadows so they perform well in the shade as well as the full sun. I wanted to bring this to your attention because of your comment “That is one of the reasons you have such a hard time growing grass under those large shade trees in your yard, no sun. Three inch grass blades and longer only serve to shade themselves, like when we wear a hat and this shade inhibits photosynthesis. ” In fact, Eco-Lawn germinates faster in the shade! You can check it out at http://www.eco-lawn.com .
I’d love for you to try it. Please be in touch and keep up the great work.
Miriam Goldberger
Widlflower Farm Inc.
http://www.wildflowerfarm.com
1-866-GRO-WILD
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I just purchased a property in Houston, TX. I’m originally from the Mid-Atlantic and then lived in New England for over 15 years. I have no experience with warm season grasses. I’m having a hard time determining if my lawn is Bermuda or St. Augustine grass. I think it is St. Augustine, because it seems much more coarse and broad leaved, but all the images I can find using a quick Google image search aren’t high enough resolution to be certain. Is there a simple way to tell the difference? I want to be sure I’m setting my reel mower to the correct height.
Thanks.
Hi Jim,
This is an excellent question.
To identify St. Augustinegrass one of the most useful characteristics is the leaf collar. While the blade and the sheath are broad, the collar is narrow and constricted. The blade usually takes a 90-degree angle from the sheath at the collar. St. Augustinegrass also has a “boat shaped tip” vs. a flat tip.
Bermudagrass has small hairs around its inner ligule (the structure which grows from the collar on the inside of the leaf). The leaf should be folded (not rounded) in vernation.
This is a great topic – we’ll be sure to talk more about this later. Please let us know if you have any more questions!