Why Is My St Augustine Grass Turning Yellow

The tropical St. Augustine grass is the warm-season grass for lawns and yards in Zones 7 to 12. Although it doesn’t need much upkeep, it rewards you for your attention with a lush, green lawn.

However, occasionally you can see the leaf blades start to turn yellow. What causes St. Augustine grass yellowing or browning? One reason is that if St. Augustine grass doesn’t get enough water or has too much water quickly, such as in too much rain, it can yellow. You can also find St Augustine grass yellow tips from nitrogen deficiency or iron deficient soil.

In our guide, we run through all the reasons such as insects, disease, excess fertilizer, incorrect mowing, and high temperatures can leave you with yellow grass. By the end, you’ll have many fixes on knowledge of how to deal with fungal diseases and brown patches and how to revive your lawn to the lush green it was. (Learn How To Kill Morning Glory)

St Augustine Grass Turning Yellow

Causes of Yellow St. Augustine Grass and Fixes

The family Poaceae includes the exceedingly decorative St. Augustine grass, perfect for lawns thanks to bluish-green grass blades forming a dense mat.

It thrives along coastlines since it can survive saline settings, but when growing conditions aren’t optimum, the leaves turn yellow and can end up leaving you with a brown patch and losing their color.

Here is a quick overview of the more common causes of yellow grass and how you can fix it.

1. Insufficient Water

The spring and summer growing season are ideal for St. Augustine grass, which prefers a consistent moisture level in the soil.

Particularly in the first year, drought causes the grass to wilt quickly and turn yellow. If you have an irrigation system for lawn care, you’ll see brown and yellow spots where your sprinklers don’t reach.

Fix: You can wait between irrigations until the top inch of the soil dries out once it has established itself. Consider the rainfall when providing the grass with 1 inch of water every week.

2. Too Much Water

For St. Augustine grass, over-watering is an issue because it causes root rot. The leaves lose their bluish-green hue because of the injury to the roots.

Fix: Check the soil’s drainage and give it time to dry between irrigations. Then, with your finger, feel the soil’s surface. The grass needs water if it’s dry; if not, wait a little longer.

3. Lack of Nitrogen

St. Augustine grass requires soil with high nitrogen content, and a lack of this nitrogen slows the development of the grass.

Fix: Apply suitable nitrogen fertilizers. However, it may take repeat applications before your grass revives to its natural colors.

4. Iron Deficiency

On the blades of St. Augustine grass, an iron deficiency results in yellow patches and streaks on the affected area.

This ailment, iron chlorosis, causes the grass to appear patchy and in various hues of yellow.

Fix: To solve this issue, apply liquid iron topically to the leaves. Using chelated iron supplements is another option.

5. Cutting Grass Too Short

Keep your St. Augustine grass between 2 and 3 inches tall when you mow it.

If you trim it below 2 inches, there’s a danger that you’ll expose the turf to intense light and sever the leaves’ nutrition supply. As a result, they become less vibrantly bluish-green.

Fix: Fertilize your lawn, and let it grow back, so the leaves regain color in the affected area over the next couple of weeks. (Read Peach Tree Leaves Turning Yellow – What To Do)

St. Augustine Grass Best Fertilizer

St. Augustine Grass Fertilization

Although St. Augustine grass needs nutrients, particularly nitrogen and iron, over-fertilization can have the unintended consequence of causing root burn.

From early spring to late summer, feed the grass every 6 to 8 weeks, and use an all-purpose grass fertilizer.

Don’t be tempted to fertilize at the end of the summer and wait until the following spring.

Spread your fertilizer from north to south in one direction. Then repeat the application going from west to east.

To avoid over-fertilizing, walk straight, and ensure your water is in after each application to avoid root burn.

Alternatives: Why Is My St Augustine Grass Turning Yellow?

Root Rot

A dangerous fungal disease called root rot causes yellowing in grass that resembles nutrition deprivation.

Not treated and controlled can cause your grass to die and thin out. You may have root rot if you notice yellow rings around your St. Augustine grass in the spring or summer.

Use an ammonium nitrogen fertilizer to stop your grass from yellowing and becoming brittle.

Use fungicide containing azoxystrobin to prevent and manage the illness by combining half an ounce with every five gallons of water, which is excellent for 1,000 square feet of grass.

Wear protective clothing when applying the mixture to your grass once every month.

Chinch Bugs

The presence of dead grass patches surrounded by circles of yellowing grass shows a chinch bug infestation.

Chinch Bugs attack when your grass is most vulnerable, which is when it has a lot of thatch and are frequent pests of St. Augustine grasses.

Apply a chinch bug spray to control a chinch bug infestation and remove thatch where they hide using a vertical mower.

Extreme Temperatures

For St. Augustine grass, the suitable temperature ranges from 60 to 80 degrees Fahrenheit.

The chlorophyll that gives the plant’s blades their green color is lost when exposed to heat for an extended period. Without chlorophyll, the blades turn yellow.

Due to “freeze injury,” a too chilly environment might harm underground rhizomes. In addition, St. Augustine grass cannot grow normally because of the excessive cold, which causes browning where new shoots have appeared. (Read Lemon Tree Leaves Turning Yellow – What To Do)

Inadequate Sunlight and Water

Warm-season grass called St. Augustine grass needs at least six hours of sunlight each day.

When the grass does not receive enough sunlight, it turns yellow as the chlorophyll in grass leaves is lost when there isn’t enough sunlight.

When a plant’s tissue is injured by cold weather or depleted of nutrients from inadequate sun exposure, yellowing takes place.

Additionally, St. Augustine grass turns yellow when it goes for a lengthy period without getting enough water.

Its leaves’ cells become dehydrated when there is not enough water. While also prohibiting roots from absorbing typical levels of nutrients.

Lack of water can also cause St. Augustine lawns to turn from dark green to a light yellowish green.

St Augustine Grass Problems and Solutions

St Augustine Grass Turning Yellow More Problems and Solutions

St. Augustine grass has a dark green hue that contributes to a lovely lawn. The grass plants have broad, flat blades. Through runners, which are aboveground stolons, the grass spreads.

It naturally grows in the southeast United States, Mexico, Texas, Central America, and South America. Many lawn keepers adore it for its elegance.

1. St Augustine grass has yellow streaks and spots

Iron chlorosis is most likely to blame for this. As a result, the blades of St. Augustine have spots and streaks of yellow tint.

When the soil lacks iron, this occurs because of your grass’s inability to absorb iron at the rate it grows; this disorder is typically seen in the summer.

This is because your soil has a high pH; to get the balance, you can send off soil samples or buy a soil pH test kit and do it yourself. Your lawn should have slightly acidic soil between a pH of 6 – 6.5

To fix this, you need to provide your lawn with iron in a form that it can easily absorb. Here, your lawn will benefit from using iron chelate and iron sulfate.

Though costly, chelated iron works best, although iron sulfate is an excellent substitute.

Iron sulfate is an acid-forming soil that not only directly provides iron to the soil but also aids in releasing the iron already there.

The best way to treat your soil’s iron shortage is to apply an iron supplement throughout the year rather than just in the summer months, such as iron sulfate, as it doesn’t offer the desired effects when you add it one time.

2. My St Augustine grass is yellow in the spring

Do you see your St. Augustine grass turn yellow in the spring?

Rains are to blame for this occurrence. The nitrogen in the soil is removed whenever it rains. Because there is not enough nitrogen in the soil, the grass turns to turn yellow.

There will be instances when the rain will leave your lawn in a state of water logging with too much standing water. St. Augustine grass can’t absorb the nutrients when grown on water-saturated soil.

If you haven’t done so, you should put some nitrogen fertilizer on your lawn in August. This fertilizer helps revitalize the soil, which is lacking in nitrogen.

If the yellow grass turns to turn brown, this is a sign that a fungal infection is present, and you will need to treat your grass with s fungicide. (Read Pumpkin Leaves Turning Yellow – What To Do)

3. My St Augustine Grass Has Yellow Circles

St. Augustine grass is susceptible to attack by a wide variety of fungi. The appearance of yellow circles on the grass blades indicates a fungal infection. Typically, just a small portion of the lawn will be affected by illnesses of this kind.

An infection with a fungus is the root cause of take-all root rot. This disease is brought on by abnormally high levels of rainfall as well as excessive fertilization.

You will need to apply a fungicide with a sprayer to the infected areas. The spring and the fall are the best times to apply this fungicide to your plants.

Myclobutanil and azoxystrobin are pretty effective in treating severe cases of root rot. Apply the solution to an area of one thousand square feet of lawn turf after combining half an ounce of water with four gallons of water.

4. Why Is My St Augustine Grass Turning Yellow In Summer?

In the summer, St. Augustine lawns succumb to chlorosis. Due to this disorder, which results from a lack of chlorophyll, the lawn may turn yellow.

Because the grass cannot absorb vital nutrients like iron and nitrogen, chlorosis results.

You can add some organic matter to lower pH and improve the grass’s ability to absorb nutrients. However, applying an acidified compost layer is best before adding the liquid seaweed with iron.

5. Why Does St Augustine Grass Turn Yellow After Adding Fertilizer?

Over-fertilizing will turn your St Augustine lawn yellow if you add excessive amounts of fertilizer, as too much fertilizer causes harm like not enough to your lawn.

The fertilizer’s excess nitrogen salts cause the grass blades to burn. Leaf scorch is the term for this. As a result, the lawn turns brown at the top and yellows at the bottom.

Only quick-release fertilizers cause this to occur. Use of slow-release fertilizers, such as Milorganite, is therefore advised.

If you’ve noticed any nutrient burn early, it is an easy fix, and all you have to do is water the affected areas as this washes away any excess salts present in your lawn.

Why Is My St Augustine Grass Turning Yellow

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