How Short Can You Cut St. Augustine Grass?

As a longtime gardener and lawn care enthusiast, one of the most common questions I’m asked is “How short can I cut my St. Augustine grass?” It’s an important thing to consider when maintaining a healthy, lush St. Augustine lawn. Over the years, through plenty of trial and error, I’ve dialed in the ideal mowing heights that keep St. Augustine looking its best.

Cutting your grass too short can damage it over time, leading to thinning, weed encroachment, and an unsightly yard. But letting it grow too tall creates its own issues with disease and mowing difficulty. There’s a careful balance to strike. The optimal height can also vary based on factors like season, variety, and more.

In this article, I’ll share the insider tips I’ve learned from decades of hands-on St. Augustine lawn care experience. I’ll provide specific recommendations for mowing height ranges based on time of year and cultivar. You’ll also learn why proper cutting length is so crucial for root development, density, and health. I’ll even cover key mowing techniques for lusher grass.

Armed with this advice, you’ll be able to master mowing height for your St. Augustine. Say goodbye to scalping, thinning, and leggy grass! Proper cutting is essential to bring out the beauty and vigor of this popular warm season lawn grass. Let’s dive in and unlock the secrets to lush, green grass that will be the envy of your neighborhood.

What is the Recommended Cutting Height for St. Augustine?

When mowing St. Augustine grass, you’ll want to maintain the blades at the proper cutting height for optimal lawn health. Through trial and error caring for my own St. Augustine turf, I’ve dialed in ideal mowing heights. Here are my top recommendations.

Start at 3-4 Inches

For most St. Augustine lawns, I suggest starting with a mowing height between 3 and 4 inches. At this cutting length, there is ample green leaf tissue to keep performing photosynthesis at a high rate to fuel growth. The grass still receives sufficient light as well.

This moderate height also enables St. Augustine’s blades and stems to elongate enough for the roots to grow deeper into the soil. The combination of robust top growth and an expansive root system makes for very vigorous, thick turfgrass.

I begin mowing my lawn at 4 inches early in spring. This provides a lot of leaf area to capture sunlight to feed rapid spring growth. Then I may adjust down slightly to 3-3.5 inches in peak season.

Adjust for Season and Variety

While 3-4 inches is ideal for most St. Augustine, the optimal height range can shift depending on climate conditions and cultivar. Here are some specific adjustments I make:

  • Raise cutting height to 4 inches or higher during summer heat to provide more leaf surface area for growth. Taller grass withstands heat stress better.
  • Dwarf St. Augustine varieties like Seville and Delmar can be kept slightly lower, 2.5-3 inches, due to their naturally shorter growth.
  • Floratam, a popular vigorous St. Augustine, thrives at a slightly higher 3.5-4 inch cut. It forms a dense mat at this height.

The proper cutting height truly maximizes each cultivar’s assets. I tweak my mower throughout seasons to optimize growth.

Never Scalp Below 2 Inches

Short St. Augustine Grass

No matter what, I never cut St. Augustine grass below 2 inches in height. That severe scalping exposes the crowns and soil, which can lead to thinning and weed invasion over time.

Such dramatic mowing shocks the grass plants as well. It stresses the St. Augustine, reducing density and leaving it prone to disease issues. Only cut below 2 inches if completely renewing a lawn.

Keeping St. Augustine at least 2.5-4 inches tall ensures lush, healthy turf. The specific height within this range depends on environmental factors and variety. Proper mowing matters!

Why is Proper Mowing Height Important?

You may be wondering why staying within the optimal mowing height range really matters for St. Augustine grass. From promoting density to building deep roots, proper cutting height provides key benefits. Here are some of the biggest reasons to mind your mowing height.

Prevents Scalping and Thinning

Mowing too short drastically thins out St. Augustine over time. Frequent scalping causes long-term damage to the crowns and stems at the base of the blades. This can lead to die off and bare patches.

Cutting at the proper height preserves ample healthy leaf tissue to keep performing photosynthesis. This fuels regrowth and maintains thick density. Proper mowing height prevents opening up bare areas prone to weed takeover too.

I adjusting mowing height instead of time between cuts to avoid removing too much leaf material at once. Gradual cutting prevents shock.

Builds Deep Root System

In addition to protecting leaf growth, maintaining adequate blade length also enables St. Augustine grass to develop a deep, extensive root system. Longer blades provide more surface area for increased photosynthesis.

This fuels the production of carbohydrates that supply energy for plants to grow roots down into the soil. Deep roots make grass more drought tolerant and nutrient efficient.

But scalping robs the grass of photosynthetic factories to power deep root development. Proper mowing height keeps your St. Augustine grass healthy both above and below ground.

Helps Grass Crowd Out Weeds

Getting your St. Augustine lawn thick and lush by optimal cutting also boosts its weed-fighting powers. Healthy, dense turf simply doesn’t leave room for weeds to sneak in and establish.

But mowing too short causes thinning and bare spots where weeds can gain a foothold. It creates openings in the turf’s protective canopy.

Maintaining proper mowing height promotes the competitive edge St. Augustine needs to choke out invading weeds. Thick grass prevents thin weeds.

Mowing Tips for Healthy St. Augustine

Now that you know the optimal cutting heights, let’s discuss some key mowing tips and techniques I use to maximize the health and beauty of my St. Augustine lawn. Proper mowing takes some finesse!

Sharpen Mower Blades

It may seem simple, but keeping your mower blades freshly sharpened makes a huge difference in the quality of cut. Sharper blades provide a clean, even snip. This helps prevent frayed, torn leaf blades that are vulnerable to disease.

Take a few minutes to sharpen your mower blades at least once a month. Or have them professionally sharpened annually before peak mowing season. The clean cut will be evident in your lush, green lawn.

Mow at Least Weekly

During active growing periods, I mow my St. Augustine lawn at least once a week, sometimes more. Frequent mowing is better than cutting off too much height at one time.

Never remove more than one third of the total blade height when mowing. For example, if your grass is 4 inches, don’t cut below 3 inches in a single pass. Stagger cutting heights over several mows instead.

Leave Clippings to Mulch Lawn

As long as your mower blades are sharp, there is no need to bag clippings after cutting St. Augustine. Letting the clippings mulch back into the lawn provides free fertilizer full of nitrogen to feed your grass.

The clippings also form a natural mat that helps suppress weed seed germination and growth. I use my bagger only when leaves or pine needles accumulate.

Proper mowing height and frequency keeps your St. Augustine lawn looking its best. And a few key tips enhance the results even further. Try them yourself for maximum lawn appeal!

Frequently Asked Questions

When it comes to mowing St. Augustine lawns, many common questions come up. Below I’ve addressed some of the key FAQs I often receive about optimizing cutting practices based on my years of experience.

How often should I mow St. Augustine grass?

During active growing seasons, plan to mow St. Augustine lawns at least once per week, and up to two or three times weekly if growth is particularly vigorous. More frequent light mowing is better than cutting off too much height all at once. Adjust your mowing frequency based on growth rate to remove no more than one third of blade height in a single pass.

When is the best time of day to mow St. Augustine grass?

The optimal time to mow St. Augustine is in the early morning or late afternoon when the grass is cool and dry. Avoid mowing midday when the heat and humidity place extra stress on the grass. Mowing when cool also minimizes evaporation after cutting the blades.

What setting should I use for mowing St. Augustine grass?

Mow St. Augustine at the highest setting possible without scalping based on your desired height, typically 2.5-4 inches. Raise your mower deck for taller grass and use lower settings only for the dwarf varieties under 3 inches. Keeping blades sharp for a clean cut also helps avoid ripping or tearing at any height.

Proper mowing practices are essential for growing a lush, green St. Augustine lawn. Let me know if you have any other questions!


Proper mowing height is crucial for luscious, healthy St. Augustine lawns. As we’ve covered, cutting too short damages the grass over time leading to thinning and weeds. But allowing it to grow too tall creates mowing challenges and disease issues. Finding the right balance is key.

I recommend starting with a 3-4 inch cutting height and adjusting from there based on season, variety, and growth rate. Never scalp below 2 inches. Monitoring your lawn and tweaking your mower height prevents shocking the grass. Proper height strengthens the turf, roots, and density.

But equipment and techniques matter too. Sharp blades, weekly mowing, and mulching clippings boost your results. Take the time to master mowing. Done right, it showcases the beautiful emerald color and texture of St. Augustine.

Armed with these insider lawn care tips, you can nail the perfect cutting height for your yard. Proper mowing will bring out the vigor and lush appearance of St. Augustine grass. Your neighbors will be envious of your expertly manicured, verdant lawn.

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