The Fall Challenge for Warm-Season Grasses
Bermuda, Zoysia, and St. Augustine have performed well throughout the summer, and now it is time to prepare the grasses for fall. As the daytime and nighttime temperatures start to drop gradually over the next 2 months, warm-season grasses will start to slow in growth and prepare for fall and winter. As the warm-season grass photosynthesizes slows, the grass diverts energy from top growth to carbohydrate storage for the colder, winter months. When this occurs, the grass is slower to recover from wear and damage, and there is a reduced response to fertilization. Through this process, the grass can't produce as much energy, which affects density, color, and growth rate.
Cooler nights plus warm, humid days create prime environments for certain diseases to develop in warm-season grasses. Grasses that become weaker in the summer heat are most susceptible to diseases going into fall. Slow-growing warm-season grasses are less competitive and allow space for weeds to establish unless pre-emergent weed control applications are performed.
When do Warm-season Grasses Grow Best?
Warm-season grasses grow best when soil temperatures are in the range of 75 - 90 degrees fahrenheit. Once soil temperatures fall below 55 degrees, growth stops immediately, and the dormancy stage begins. Carbohydrate storage begins in the roots of the grass, rhizomes, and stolons. The carbohydrate reserves help the plant survive and provide fuel for spring green-up.
Over-fertilization with high nitrogen lawn fertilizer in the fall diverts energy away from the stored carbohydrates, which could make the turf weaker the following spring. Sunlight becomes less and less as fall arrives, which reduces the amount of UV rays. With this reduction in light, less energy can be produced, and the grass starts to decline faster in the fall when compared to summer.
How to Prepare Grass for Winter
Once the process of dormancy begins, the grass slows its growth and hardens off. Cell walls within the grass plant thicken, metabolism slows, and chlorophyll production decreases. This process is essential to surviving cold temperatures, even in the deep South. Regional time difference does affect the length of growing time and entering into dormancy. The deep south and coastal areas' growth can continue late into the fall. The “Transition Zone” shutdown can start as early as September and be completely dormant by late October, first of November. The subtropical regions sometimes provide mild winters that allow for continual growth, and the plant doesn't fully go dormant.
Proper Fall Lawn Fertilizer & Grass Care
Fall is a time to prepare the warm-season grasses to go to rest and sleep for the winter months. It is a time to protect, strengthen, and prepare for spring. Avoid high rates of nitrogen fertilizer in the fall while increasing K (potassium fertilizer) for winter hardiness. Maintain a consistent mowing height until dormancy occurs. Reducing the amount of traffic on warm-season grasses in the fall and winter will aid in spring greenup.
Fertilization in the fall is important for warm-season grasses. Avoid heavy nitrogen (N) applications after early fall because new, tender growth will be susceptible to frost. Potassium-rich formulas like Simple Lawn Solutions 3-18-18 or 0-0-25 can be applied to harden off the plant tissue and potentially protect from colder temperatures, and should be applied in early fall.
Maintain the recommended mowing heights (e.g., Bermuda: ½” - 1.5”, Zoysia: ½” - 2”) and avoid scalping going into fall, as this can reduce energy reserves going into dormancy. Reduce the frequency of irrigation, but avoid warm-season grasses going into drought going into the fall. Water as needed if rain hasn’t occurred in a while. Apply pre-emergent herbicide for winter annual weeds before temperatures fall below 70 degrees.
Core aeration plus application of Simple Lawn Solutions Soil Loosener will aid in soil management by increasing air and water in the rootzone. Applying Simple Lawn Solutions' humic acid soil amendments, like Seaweed Soil Hume or Root Hume, is great for soil health in the fall on warm-season grasses.
Mowing too Low, Over-fertilization, Disease Prevention, and Neglecting Soil Health in Your Lawn
Mistakes can be made when managing warm-season grasses going into fall. First, manage the amount of nitrogen being applied so as not to overstimulate the grass. New growth going into fall is vulnerable to frost and colder temperatures that occur at night. More focus should be directed towards the root system and soil by adding low-N and more potassium-rich fertilizers early in the fall.
Mowing too low, or scalping, before dormancy is not recommended because there is less leaf tissue for photosynthesis to take place. Additionally, scalping can weaken the grass going into winter. Maintaining the recommended height of cut is best to protect against colder temperatures.
Ignoring weed prevention is a common mistake that is made in the fall. Winter annual weeds such as poa, chickweed, and henbit germinate in early fall. Without using pre-emergent herbicides, weeds will take over slow-growing turfgrass.
Neglecting soil health in the fall of the year can lead to issues in the spring. Soil compaction and firmness can alter the root zone by not having pore space for air and water, and poor infiltration can increase disease risk. It is best to core aerate and apply humic acid products from Simple Lawn Solutions. Watering deeply and infrequently will allow soil to maintain moisture but not become overly saturated.
Skipping disease prevention is not recommended on warm-season grasses in the fall. In some regions, diseases like large patch, spring dead spot, leaf spot, take-all root rot, dollar spot, and pythium root rot can occur. Slower turf growth means less energy to recuperate from disease activity. Cooler temperatures and increased leaf wetness times are perfect conditions for diseases to grow.
Regional Timing Tips
1. Deep South (USDA Zones 8–9)
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Typical dormancy: Late November to January (if at all in the far south).
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Fertilization: Continue moderate feeding until mid-September; shift to low-N, high potash fertilizer by late September.
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Weed control: Apply pre-emergent for winter weeds early to mid-October when soil temps approach 70°F.
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Disease watch: Large patch can flare from late September through November — apply fungicide preventively if there’s a history.
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Traffic: Still warm enough for recovery through early fall, but recovery slows significantly by late October.
2. Transition Zone (USDA Zones 6–7)
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Typical dormancy: Late October to mid-November.
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Fertilization: Stop high-N applications by late August or early September; apply K-rich fertilizer in early September to strengthen roots.
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Weed control: Pre-emergent by early September for winter annuals (earlier than Deep South due to cooler nights).
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Disease watch: Large patch and spring dead spot prevention treatments should be made in September when soil temperatures drop into the 70s.
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Traffic: Growth slows rapidly by early October — avoid heavy play to reduce wear scars.
3. Coastal & Subtropical Areas (Southern FL, South TX, Gulf Coast)
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Typical dormancy: May not go fully dormant; growth slows in cooler months.
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Fertilization: Can extend moderate feeding through October, but reduce N as nights drop below 65°F.
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Weed control: Watch for prolonged weed germination due to mild winters; split pre-emergent applications in October and January.
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Disease watch: Large patches can be active from October to March in these climates.
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Traffic: Recovery is possible most of the year, but is still slower from November–February.
4. Desert Southwest (AZ, NV, SoCal Warm Zones)
- Typical dormancy: Late November to December.
- Fertilization: Reduce N by mid-September; in overseeded turf, manage fertilization for cool-season overseed without overfeeding dormant warm-season base.
- Weed control: Pre-emergent timing varies — often late September before winter rains.
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Disease watch: Less common due to dry climate, but a large patch can occur in irrigated turf during cool, wet periods
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Traffic: Overseeding can mask dormant turf wear but requires careful management to avoid damaging the base grass.
Preparing your Lawn for Next Spring
The best spring green-up starts in the fall. By prioritizing root strength, soil health, and proactive pest/disease management now, warm-season turf will enter dormancy strong and come out of it faster, denser, and healthier. The steps that are taken in the fall on warm-season grasses will determine how it wakes up in the spring. Don’t overfertilize and stimulate new growth during a time when growth needs to slow down. Soil testing is a sure way to know what nutrients and how deficient or abundant they may be for the plant to wake up next spring, 2026.
