When To Fertilize Lawn In South Texas

Knowing when to fertilize lawn in South Texas is the key to keeping your grass healthy through the heat and sporadic weather. Getting the timing right makes all the difference between a thriving green space and a constant battle with brown patches.

This guide cuts through the confusion. We’ll walk you through the essential seasonal lawn care schedule tailored specifically for South Texas’s unique climate. You’ll learn exactly what to do and when to do it, from fertilization to watering and weed control.

Your fertilization schedule in South Texas revolves around two main growing seasons: spring and fall. The intense summer heat puts your lawn under tremendous stress, so fertilizing at the wrong time can actually cause harm.

The golden rule is to feed your lawn when it’s actively growing, not when it’s dormant or struggling in extreme heat.

Spring Fertilization: The First Major Feeding

Spring feeding kickstarts your lawn’s growth after the mild winter. The ideal time is after the last frost has passed and your grass has fully “greened up.” This is usually from late February to mid-March in South Texas.

Watch for soil temperature. When it consistently hits about 65°F at a 4-inch depth, your grass roots are awake and ready to feed.

Use a high-quality, slow-release nitrogen fertilizer.
A 3-1-2 or 4-1-2 ratio (Nitrogen-Phosphorus-Potassium) is often a good choice for our soils.
This first feeding builds strong roots and dense turf to crowd out weeds.

Summer Caution: Proceed with Care

Summer is not the primary fertilizing season. Applying high-nitrogen fertilizer in peak heat can burn your lawn and promote rapid, weak growth that succumbs to drought and disease.

If your lawn looks pale in early summer, a very light application of a slow-release fertilizer in late May or early June might be okay. But often, proper watering is more important than food during this time.

Fall Fertilization: The Most Important Feeding

This is the non-negotiable, critical application for South Texas lawns. Your goal is to fertilize in early fall, around late September to October.

The summer heat is breaking, and grass enters a vigorous growth period. This feeding strengthens the root system for the winter and stores energy for a strong spring green-up.

Choose a fertilizer similiar to your spring blend, focusing on slow-release nitrogen.
This is also the perfect time to apply a winterizer fertilizer later in the season, which is higher in potassium to boost cold and drought tolerance.

Winter: A Time for Rest

Do not fertilize in the winter. Your warm-season grasses (like Bermudagrass, St. Augustine, and Zoysia) are dormant. Fertilizing now feeds winter weeds instead of your lawn.

How to Apply Fertilizer Correctly

Mow your lawn a day or two before you plan to fertilize.
Use a calibrated broadcast spreader for even coverage. Hand-spreading often leads to streaks and burns.
Apply fertilizer to dry grass, then water it in lightly. This helps the granules dissolve and move into the soil without washing away.
Always follow the product’s label rates precisely. More is not better.

Choosing the Right Fertilizer for Your Grass Type

Your grass type influences your product choice. Here’s a quick breakdown:

Bermudagrass: Thrives on regular feeding. It handles a bit more nitrogen and benefits from 4-5 applications per year in a strict schedule.
St. Augustine: Requires consistent feeding but is sensitive to over-fertilization. Stick to 3-4 applications max with a balanced, slow-release formula.
Zoysiagrass: Has lower nitrogen needs. It typically does well with 2-3 feedings per year, one in spring and one or two in fall.

The Full Seasonal Lawn Care Schedule

Fertilizing is just one piece of the puzzle. Here’s your round-the-year checklist for a healthy South Texas lawn.

Late Winter / Early Spring (February – March)

Apply pre-emergent herbicide to prevent spring weeds like crabgrass.
Sharpen your mower blades. A clean cut prevents disease entry and stress.
Apply your first round of fertilizer as grass greens up.
Begin mowing regularly, setting your blade to the recommended height for your grass type.

Late Spring / Early Summer (April – June)

Monitor for signs of insect pests like grubs or chinch bugs.
If needed, apply a light, slow-release fertilizer in early June.
Adjust your watering schedule as temperatures rise, aiming for deep, infrequent soakings.
Treat for weeds with post-emergent herbicides if they appear, being careful to choose a product safe for your grass.

Peak Summer (July – August)

This is survival mode. Your focus shifts from growth to protection.

Raise your mower blade height by about 1/2 to 1 inch. Taller grass shades the soil, conserving moisture and protecting roots.
Water deeply and early in the morning, about 1-1.5 inches per week, including rainfall.
Avoid any nitrogen-heavy fertilizers. If you must, use an organic, micronutrient-rich product instead.
Watch for fungal diseases like brown patch, which thrive in hot, humid conditions.

Fall (September – November)

Apply your crucial fall fertilizer in early fall.
Apply a second pre-emergent herbicide to prevent winter weeds like poa annua and henbit.
Core aerate if your soil is compacted. This allows water, air, and fertilizer to reach the roots.
Apply a winterizer fertilizer in late fall (October-November) to build hardiness.
Gradually lower your mower blade back to its normal height as growth slows.

Winter (December – January)

Mow only occasionally if needed.
Water only during extended dry spells to prevent desiccation.
This is a great time to service your lawn equipment so its ready for spring.
Plan any major landscaping changes for the upcoming season.

Essential Lawn Care Tips for South Texas Challenges

Watering Wisely in the Heat

Overwatering is as common a problem as underwatering. Your goal is to encourage deep root growth.

Water early in the morning (before 10 AM) to reduce evaporation and fungal growth.
Provide about 1 inch of water per session, enough to moisten the soil 6-8 inches deep.
Water less frequently but deeply. A good schedule might be 1-2 times per week, depending on rainfall and temperature.

Mowing for Health and Resilience

How you mow directly impacts your lawns health.

Never remove more than 1/3 of the grass blade in a single mowing.
Keep your mower blades sharp. Dull blades tear grass, creating brown tips and open wounds for disease.
Vary your mowing pattern each time to prevent soil compaction and rutting.

Managing Common Weeds and Pests

South Texas lawns face specific invaders.

Weeds: A consistent pre-emergent schedule in spring and fall is your best defense. For existing weeds, identify them and use a targeted post-emergent.
Grubs: If you see irregular brown patches and can easily pull up turf, you may have grubs. Treat with a curative product in late summer.
Chinch Bugs (St. Augustine): Look for yellowing patches that turn brown, especially in sunny areas. Confirm by flushing a section with soapy water; bugs will float to the surface.

Frequently Asked Questions (FAQ)

What month is best to fertilize in South Texas?

The two best months are March for spring feeding and late September for the critical fall feeding. Timing can shift slightly based on your specific location and that year’s weather patterns.

Can I fertilize my lawn in the summer in Texas?

It’s generally not recommended. The stress of high heat combined with fertilizer can damage your lawn. Focus on proper watering and mowing instead, and save the fertilizer for early fall.

When should I put down pre-emergent in South Texas?

Apply your first pre-emergent in late winter (February) before soil temperatures reach 55°F for several days. Apply the second application in early fall (September) to block winter weeds.

Is it too late to fertilize in October?

October is still a good time for your fall fertilizer application in South Texas. If you havn’t applied a winterizer yet, late October into early November is ideal for that step.

How often should I water my lawn in South Texas summer?

During peak summer, water 1-2 times per week, providing about 1 to 1.5 inches of water total per week. Always adjust based on recent rainfall. Watering deeply and less frequently is far more effective than daily light sprinklings.

Sticking to this South Texas seasonal lawn care plan takes the guesswork out of maintenance. By fertilizing at the right times—especially that vital fall feeding—and combining it with smart watering and mowing, you’ll build a lawn that can better withstand our challenging climate. Remember, consistency is more important than perfection. Start with a soil test if you can, as it provides the best blueprint for exactly what your soil needs to support a lush, healthy lawn.