Spring Care Tips for Your St. Augustine Lawn

With the arrival of spring comes colorful, blooming flowers, singing birds and the return of green St. Augustine lawns. Spring care for your St. Augustine is just around the corner and for us lawn and garden lovers, this is an exciting time of year!

It’s important to note that seasonal St. Augustine maintenance slightly differs each season as temperatures and soil conditions change. In the spring, St. Augustine is just starting to come out of dormancy and turn green again.

Depending on where you’re located, your St. Augustine may not have even gone dormant at all!

Read on for a list our turfgrass experts put together on some of the most important spring lawn care tips for your St. Augustine grass going into the spring season.

Be sure to also refer to our St. Augustine Homeowner Maintenance Guides for generic St. Augustine, Palmetto® St. Augustine and CitraBlue® St. Augustine. Each maintenance guide is divided into sections for spring, summer and fall maintenance.

Want us to do some of the spring lawn care for you?

If so, check out the Lawnifi Complete Program! The Lawnifi Complete Program is a year-round subscription for seasonal lawn care—specific to your grass type—delivered to your door. Our boxes include everything your lawn needs in one lawn care subscription. Products are curated by our turfgrass experts for each active growing season. Delivered spring, summer and fall.

Watch our series of St. Augustine spring lawn maintenance tips in the playlist below. Select the icon in the top right-hand corner to navigate through the playlist.

Jump to…

• 1. Begin Mowing Your Lawn at the Proper Height Again
• 2. Start Your Lawn Off Right with the Appropriate Spring Fertilizer This Year
• 3. Set Up a Spring Irrigation Schedule
• 4. Control Weeds with a Pre- or Post-Emergent Herbicide
• 5. Watch Out for Insects That May Begin Coming Out
• 6. Prevent Disease as Temperatures Begin to Warm Up

1. Begin Mowing Your Lawn at the Proper Height Again

The timing for which the first mow of the spring for your mature, established St. Augustine widely varies depending on the area you live in. St. Augustine can come out of dormancy differently depending on the environment and temperatures your area encounters.

For example, if you live in South Florida, your St. Augustine may have never entered dormancy at all during the winter. Many homeowners who live in South Florida will mow their lawn every other week during the winter—oftentimes starting in September and resuming a regular, weekly mowing schedule again in mid-March.

Generally speaking, mid-March is about the time for you to begin your regimen for spring green-up and mowing. It’s important to note that the first mow of the spring shouldn’t take place while your St. Augustine lawn is dormant—wait until it’s actively growing again before mowing and never remove more than a third of the leaf blade or you may risk scalping the lawn.

Keep your St. Augustine between 2–4 inches in height. However, these heights slightly vary for different cultivars of St. Augustine. For example, Palmetto should be maintained at a height of 1.5–2.5 inches whereas CitraBlue should be kept at a height of 2–3 inches during the spring.

Lastly, a good tip for spring is to make sure your lawn mower blades are sharpened so that the mower blades neatly slice through the grass in place of ripping them. If the grass blades aren’t cut neatly, the mower is ripping them and opens the grass up to the possibility of disease.

Performing regular maintenance on your mower is good practice for the end of the mowing season or before spring takes place.

2. Start Your Lawn Off Right with the Appropriate Spring Fertilizer This Year

With most St. Augustine grass coming out of dormancy, the spring is one of the most important times to use fertilizer. The best fertilizer for St. Augustine grass needs to promote healthy roots and the return of green leaf blades.

Be careful when making your first St. Augustine fertilizer application of the year though—it is common for homeowners to see their grass green up and immediately pull out the fertilizer and lawn mower.

We advise that you typically wait until the last frost has hit. If you fertilize your lawn and another frost hits, your St. Augustine will go right back into dormancy and you’ll have a harder time getting it to green up again. This does more harm than good.

The date of the last frost varies from location to location. In the Florida Panhandle, for example, St. Augustine may not go dormant and will reach its full green-up in early February (depending on how cold the winter was).

Even then, you won’t want to apply fertilizer until after Easter once the last frost has passed. Refer to the Farmer’s Almanac to figure out the last frost date for your area in 2023.

Sod University recommends two different options for St. Augustine spring fertilization: Lawnifi® Foundation, a slow-release granular option that comes in 25 lb. bags and lasts for three months, and our Lawnifi Spring Fertilizer Box, a liquid fertilizer program that includes three bottles of liquid fertilizer that can be applied monthly with a hose-end sprayer.

Each of the two options are great St. Augustine grass fertilizers that cover 5,000 sq. ft. Learn more in Granular vs. Liquid Fertilizers or by clicking the two products listed below.

Our patented nano-fertilizers with Catalyst Technology^TM give your St. Augustine lawn the jump-start it needs to emerge from dormancy, green up fast and thrive throughout the spring months.

Read Why Use Lawnifi Fertilizer? for more information about Lawnifi.

Next, it is important to mention that you may start to notice spots of brown or straw-like grass while the rest of your lawn comes out of dormancy. This is usually a sign of disease.

You do not want to apply fertilizer to a lawn with disease as the nitrogen in the fertilizer will feed the disease and promote its growth. Apply a systemic fungicide first and then wait several weeks before following with a fertilizer application.

3. Set Up a Spring Irrigation Schedule

Dormant St. Augustine doesn’t need much water until the active growing season kicks in and your grass starts to green up. In our Winter Lawn Maintenance Tips article, we state that if you have a dormant, warm season lawn, it is not dead—it’s just “sleeping”.

Although dormant grass requires much less water than it would while it is actively growing, it will still need water. Once it starts to come out of dormancy, St. Augustine requires about 1 inch of water per week including rainfall. The same can be said for the different brands of St. Augustine like Palmetto or CitraBlue.

If you aren’t sure how to measure how much water your lawn is receiving, an irrigation audit may be beneficial to you. Irrigation audits provide measurable information about how much water each area of your lawn is receiving within a given amount of time.

If you’re a homeowner who lives far enough south and your St. Augustine doesn’t go dormant during the winter, you may continue to regularly water your lawn in the winter.

However, if you live in South Florida, for example, you may turn your irrigation off completely during the winter and during the months of June–August when it rains a lot. The atmosphere in South Florida isn’t usually evaporating much water and the grass isn’t using it much during the winter, so frequent irrigation isn’t needed.

The next few tips in this article discuss spring applications for fungicides, herbicides or insecticides. If any of these control products or fertilizers are granular, you will need to water the product in so that your lawn absorbs it. This means that you will already be watering your lawn with the appropriate amount of water during the week of application.

The same can be said with any liquid products as they are either products that attach to the end of your garden hose or require tank mixing with water.

Above all, read and follow label instructions thoroughly before watering any products in.

4. Control Weeds with a Pre- or Post-Emergent Herbicide

Pre-emergents should be applied during the spring when ground temperatures reach about 55 degrees Fahrenheit. A pre-emergent herbicide functions to prevent weeds from emerging from the surface of the soil, as its name suggests.

The exact dates for these applications differ depending on the area you live in, but generally speaking, pre-emergents should be applied between the beginning and middle of March in the spring.

For more information, read our blog on spring pre-emergent applications and refer to our recommended pre-emergent herbicides below. 

Apply post-emergent herbicides throughout the spring as needed to control summer annual and perennial broadleaf or grassy weeds like knotweed, spurge, sandspur, dallisgrass, dandelion, chickweed, dollarweed, doveweed, lespedeza, crabgrass or goosegrass.

Atrazine-based post-emergents like the ones below are the most effective control product for St. Augustine lawns. They also serve as an excellent pre-emergent herbicide.

Be sure to follow product labels appropriately during application. Lastly, if you notice weeds and you aren’t sure which type of weed it is, check out our Identifying Common Lawn Weeds blog.

Note: St. Augustine and centipede lawns are sensitive to active ingredients like 2,4-D, MSMA or Mecroprop. Apply an Atrazine-based weed control product like Hi-Yield Atrazine to control weeds. Hi-Yield Atrazine serves as pre- and post-emergent herbicide and is the best spring lawn treatment for both grass types.

Pictured above from left to right: Crabgrass, goosegrass, clover, dollarweed, knotweed, spurge, lespedeza and doveweed.

5. Watch Out for Insects That May Begin Coming Out

If your lawn has suffered from insect damage around this time in the past, it is a good idea to apply a broad spectrum insecticide at this time to prevent them from coming back again. If the insecticide is a granular product, be sure to water it in so that it soaks into your soil. On the other hand, if it’s a liquid product, you will either need to attach it to the end of your garden hose or tank mix it.

Some of the most common spring insects in St. Augustine are white grub worms and chinch bugs.

Sod webworms are typically more of a summer or fall pest, however, they can still cause a significant and costly nuisance to lawns located throughout the Southern regions of the U.S. during the spring season.

Acelepryn is often used to treat currently existing grub worm infestations that may show up in the summer whereas Imidacloprid-based products like Imidacloprid 2F, which is included in the Lawnifi Complete Program, Merit 0.5 G and Merit 2F prevent them as it begins to warm up in the spring.

Bifenthrin products like Hi-Yield Bug Blaster Bifenthrin, Bifen L/P and Bifen XTS are also great for chinch bug or sod webworm infestations.

You can read more about these insects in our Insect Identification blog. Refer to some of our most popular and effective insect control products below and read product labels thoroughly before application.

Pictured above from left to right: White grub worms and a Southern chinch bug.

6. Prevent Disease as Temperatures Begin to Warm Up

As previously mentioned, disease may start to show up as St. Augustine comes out of dormancy. If this is the case, you may need to make applications of a systemic fungicide.

St. Augustine may be prone to gray leaf spot, a disease that shows up around this time that looks like little gray/brown spots on St. Augustine leaf blades.

If you notice any disease outbreaks, you may need to make applications of a systemic fungicide like Azoxy 2 SC Select, which is included in the Lawnifi Complete Program. Even if you don’t have disease in your lawn, it’s still good practice to apply it preventively to keep disease from taking over—especially if you’ve had disease in the past around this time.

Systemic fungicide applications should take place before you apply any spring fertilizer. If you have fungus in your lawn, the nitrogen found in fertilizers oftentimes feeds it and helps it spread. Apply a systemic fungicide and wait a few weeks before applying any fertilizer.

Read product labels thoroughly.

Pictured above: A closeup of gray leaf spot in St. Augustine grass.

There are a few other optional things that can be done to help your lawn thrive in the spring.

Before the onset of summer heat, lawn patchwork and light top dressing with a sand and topsoil mix is a great way to recover any weak areas. Plugs can be purchased to fill in areas of the lawn with bare spots. Learn more here.

Aerating your lawn is also an ideal way to help deliver nutrients and really break up compacted soils. We typically recommend doing this once every couple of years. If you notice thatch that is thicker than 1⁄2 inch, dethatch in late May. Read more in Aerating vs. Dethatching.

Spring maintenance tips differ from other practices that take place during the rest of the year. The weather starts to warm up and everything will turn green again. Be sure to check out our individual Homeowner Maintenance Guides for generic St. Augustine, Palmetto® St. Augustine and CitraBlue® St. Augustine.

If you have a new lawn and are looking to learn about spring lawn care treatment for new sod, we recommend starting with our establishment guide for the first 30 days after installation and then transitioning to one of the maintenance guides here.

And remember…if you want lawn care made simple, the Lawnifi Complete Subscription provides your lawn with what it needs during the current season and for years to come.