PINELLAS COUNTY, FLORIDA - Helpful information about Pinellas lawns & landscapes.

Your Mower is Killing Your Lawn

St Augustine Looks Best When Kept Tall
A St Augustine Lawn Looks Great and Thrives at 5" Mowing Height

Your mower is killing your lawn because you mow too low. A St Augustine lawn, to be sustainable (to survive, to be hardy, to thrive), must have a minimum canopy height of 4” to 5”.

How Mowing Too Low Happens

It’s all about the look. A freshly mowed lawn looks good because it is level. To make a lawn level, all the grass must be the same height which forces you to mow the lawn at or below the shortest grass in the lawn. At that setting the entire lawn will be short but level. The shortest grass is the weakest, thinnest part of the lawn – so mowing as low as the shortest grass dooms the rest of the lawn to the same fate. In the short term (after mowing), the lawn is level and looks great. In the long term, a short level St Augustine lawn will be a weak, thin lawn.

Why It Happens

St Augustine lawns do not grow uniform. Some areas are wet, some dry, some shady, some sunny - causing the lawn to grow at different rates. This uneven growth makes for an uneven lawn. The cure is to level it with a mower – just mow the lawn as short as the shortest grass.

What is the Solution?

Although the lawn will grow at different rates, all the lawn will grow to a height of 4” to 5” – eventually.  Once the shortest grass reaches 4” to 5”, mowing at that height – 4” to 5” - will create a smooth level lawn that looks great and is sustainable.

4” Lawn - How to Get There

Growing a lawn to a sustainable height or 4” to 5” tall can be done in two ways: 1) do not mow until the shortest part of the lawn is 4” to 5” tall or 2) set your mower to mow at 4” to 5” and mow on a regular schedule. Option 1 is the easiest – just let your lawn grow until the shortest part of the lawn is 4” to 5” tall. This may take months depending on the time of the year and the lawn will uneven with a lot of showy tall weeds. To mow the lawn, set your mower so the lawn is 4” to 5” tall (usually the highest setting) and mow the lawn. 

For Option two, set you mower to mow at 4” to 5” tall and mow the lawn on your regular schedule. It will seem odd that portions of the lawn are not being cut and the lawn will look uneven. Do not despair, eventually all the lawn will be 4” to 5” tall, level and sustainable.

 A third option is to combine Option 1 &2 – when you can’t stand the look of the lawn, mow at 4” to 5” tall. This will keep the lawn more acceptable – not level but presentable - while the canopy reaches the 4” to 5”.

All three options require you to delay gratification and to suffer with a “uneven” lawn for a season or more. The upside is that once the lawn reaches the sustainable height of 4” to 5” tall, you will be rewarded with a better lawn - a lawn that is durable, hardy, greener, require less water and recover quicker form damage or stress.

Be Patient - Your Reward is a Better Lawn

The homeowner is most likely to delay gratification with the promise of a better lawn. Getting out of mowing the lawn and improving the lawn is a win/win for the homeowner.

The least likely to delay gratification is the professional. The professional knows that a level lawn looks best, and an uneven lawn will not. And they want the recognition and possible more work from neighbors who see their “good” work. To raise the mower to the sustainable heights, will mean they lawn will be uneven and reflect poorly on their work.

The solution is to set a measurable standard of the professional's work and avoid terms like “attractive” or “best appearance”. Here is a suggested standard: After mowing, the tallest part of the lawn must be 4” tall as measured from the soil surface to the tip of the leaf. You can reassure your mow guy this is what you want, and you understand that his may not be the best look after mowing. If the mow guy persists on mowing too low, refuse to pay for any mowing that does not achieve this minimum standard. Most professionals will quickly raise the mower to be paid.


Related Articles: 

You Should Mow Your St Augustine Lawn at 3" and Here's Why

Lesson #1 - The Best Mowing Height for St Augustine Turf Grass Lawn

St Augustine Grass Mowing Height

Article by Rick Orr
APL Lawn Spraying Inc.

Rick Orr is the creator of, an Agronomist and the Owner/Operator of APL Lawn Spraying. Rick is a graduate from VA Tech in Agronomy (Turf Ecology). He has been a Golf Course Superintendent, Certified Arborist, Landscape Contractor, Irrigation Contractor and Adjunct Professor for Environmental Horticulture.

Rick is an expert at growing St Augustine turf. Since 1995, Rick has spent his time researching, developing and testing the best management practices for St Augustine turf grown in Pinellas County.

The results of that work is a one of the top rated lawn spray companies in Pinellas County – APL Lawn Spraying. APL Lawn Spraying is a family owned business serving residential and commercial properties in Pinellas County, FL.

APL Lawn Spraying provides lawn spraying to commercial properties, HOA’s and single family homes. To request a free quote for your property, click here: Free Advice or Price Quote

Speaking Engagments - Does it seem like you are only hearing one side of water restrictions, fertilizer bans, plant restrictions and many other urban landscape hot topics? Rick Orr is available for speaking engagements for your HOA, Community or Professional Association or Garden Club about a variety of subjects. Call or email for more information.

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