When to Fertilize St. Augustine Grass In Texas

Frisco, Fertilizer, Fertilization, Bermuda Grass, Lawn, LandscapingSt. Augustine grass is a Texas favorite, due to its resilience and it’s deep green blades. With broad leaves and thick roots, it provides a hardy, weed-resistant ground cover. 

With all manicured lawns, it’s important to know exactly what your grass type needs in order to stay healthy. Let’s explore some important information about maintaining a vibrant bed of St. Augustine grass. 

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St. Augustine Grass 101

Basic Features

St. Augustine grass has a medium to dark green color with dense consistency. It also has a low, compact growth habit. It grows well in almost all types of soil. Moreover, it tolerates shade, heat, salt and, to a certain extent, drought. However, it does not endure flooded land or prolonged periods of cold weather.

Growth Habits

St. Augustíne grass is an aggressive species. It spreads rapidly through the soil growth “branches” called stolons. If managed correctly, St. Augustine grass forms a dense cover that easily handles light foot traffic. Also, this thick cover competes well with most weeds, as they have a difficult time taking root.


St. Augustine is the most resistant shade grass in hot weather. Texas Common, Raleigh, Seville, Palmetto, and Floratam are some varieties of St. Augustine commonly used in the south. For successful, low maintenance lawn care, breeds like this one are a wise choice for North Texas homeowners.

A Simple Guide

Fertilizing 101

The best way to determine when to apply spring fertilizer to St. Augustine grass is to monitor its growth. There’s no need to apply any fertilizer until after it has grown enough to warrant mowing. Additionally, a good rule of thumb is to wait until about 3 weeks after it’s begun turning green. This way, fertilizer isn’t wasted on grass that’s not yet active.

Annual Schedule

A good annual schedule for fertilizing is about every 8 weeks, but there are some specifics to keep in mind. For instance, it’s important to apply a second round of fertilizer later in the spring, when your grass is in its maximum growth period. This optimizes the amount of nutrients it will soak up.

However, doing this too late in the season, when the daily temperatures are averaging above 90*, is hazardous. While fertilizers are made from naturally occurring compounds, they can still burn your lawn if applied during high heat.


Nitrogen is the most critical compound in fertilizer for North Texas lawns. Most modern formulas have less phosphorus than they once had, due to accumulation problems. Phosphorus is the formulation number of the medium. The first number indicates the percentage of nitrogen. However, the third and the last number represents the percentage of potassium.

Next, determine if you want a high, medium or low maintenance site. If you want a high-maintenance lawn, use the maximum amount of fertilizer specified in the bag. Lush growth will occur, and a lawn cut will be required once a week. The irrigation needs will be more significant and the potential for diseases, such as brown spots, will increase.

Fertilizing- March to May

When to Start

As we mentioned before, you want to start fertilizing three weeks after the grass turns green. This is when there is little chance of a late frost. Apply 1 pound of soluble nitrogen per 1,000 square feet of turf every eight weeks or 1½ pounds of slow-release nitrogen every ten weeks.

Soil Testing

Has your soil been analyzed to determine what additional nutrients your lawn might need? For information on soil testing procedures, contact your county extension agent. If you, however, have not analyzed the soil, use a complete fertilizer with a ratio of nitrogen, phosphorus and potassium 3-1-2. For Examples: 15-5-10, 21-7-14, etc. Each bag of fertilizer has The analysis nutritional printed on the bag.


To determine the amount of fertilizer needed to equal 1 pound of nitrogen per 1,000 square feet, divide 100 by the first number in the fertilizer analysis. For example, if you are using a 15-5-10 fertilizer, then you need 6.6 pounds per 1,000 square feet. To determine the amount needed to apply 1½ pounds per 1,000 square feet, replace 150 per 100.
100 ÷ 15 = 6.6

Then determine the size of the area for fertilization. If your lawn measures 5,000 square feet, you will need 33 pounds of fertilizer 15-5-10. (5,000 ÷ 1,000) x 6.6 = 33 pounds of fertilizer

Fertilizing- June to September

Additional Calculations

Continue the fertilization program started in the spring, applying 1 to 1½ pounds of nitrogen per 1,000 square feet every 8-10 weeks. Without soil test information, it is advisable to use ½ a fertilizer containing only nitrogen (21-0-0, ammonium sulfate) or having a low phosphorus content; for example: 03/06/21 or 15- 0- 15 to reduce the possibility of excessive accumulation of phosphorus in the soil. Such accumulations can lead to iron and zinc deficiencies.

Preventive Actions

Moreover, to prevent yellowing caused by ferric (iron) chlorosis, apply liquid or granular iron fertilizer throughout the growing season. Follow the instructions on the label for the application rate. Iron-based fertilizers can stain cement, brick or stone surfaces.

Fertilizing- September to February

Continue to fertilize as recommended for up to 4-6 weeks before the first frost sets in. At that time, apply a low-nitrogen and potassium fertilizer, for example, 5-10-10. Do not use more than ½ pound of nitrogen per 1,000 square feet. To calculate the amount of product needed per 1,000 square feet, replace 50 percent in the spring formula.

applying lawn fertilizerConclusion

Every homeowner has different goals with regards to achieving an ideal landscape, and what that looks like for them. Thus, there is no “one size fits all” for appropriate lawn care measures

Balancing Priorities

If you want a low maintenance lawn, consider what you would to do achieve an over-the-top landscape, and go in the opposite direction. You probably will not win the “yard of the month” award, but you will spend less time and money on lawn maintenance. The decision is yours.

Playing it Safe

Are you worried about the development of winter weeds? Plan to apply an approved herbicide by the end of this autumn. These products stop weed sprouting and kill emerging seedlings. Read the precautions on the label and use the product according to label recommendations. With proper maintenance, you can help keep your St. Augustine lawn healthy and attractive.


  1. Fertilizer Schedule For St. Augustine Grass
  2. Best Lawn Care Tips for a Good Garden
  3. When to Fertilize Bermuda Grass in Texas
  4. When to Apply Lawn Fertilizer
  5. Fall Lawn Care Tips
  6. When to Fertilize Your Lawn in Texas

4 thoughts on “When to Fertilize St. Augustine Grass In Texas”

  1. Is it better to skip fertilizing St Augustine in May since it is real green & do it in Oct. ?
    We live in San Antonio.

  2. my st. augustine yard is shaded 99% of the time and is well established, yet it is becoming sparse in areas . have not fertilized in 2 years. i need help, in n. texas!


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