Winter Kill in Warm Season Turf: What You Need to Know
Winter kill in Warm Season Turf can cause severe damage, but the right care can help prevent it.
Did you know that rapid temperature drops below 23°F can cause lethal damage to your lawn? Many homeowners are shocked when brown patches appear in their turf come spring. Unfortunately, winter kill isn’t always noticeable until the damage is done.
At Vinedresser Lawn and Landscape, we help homeowners in Wilmington, NC, keep their warm-season lawns healthy year-round. Understanding what causes winter kill and how to prevent it can save your lawn from severe damage. In this guide, we’ll cover:
- What winter kill is and how it affects warm-season turf.
- The key causes of winter damage, including surprising factors you may not expect.
- Simple yet effective tips to protect your lawn during winter.
Factor | Description |
Winter Kill Definition | Occurs when freezing temperatures damage turfgrass cells, leading to dead patches in warm-season lawns. |
Main Causes | Includes direct low temperatures, winter desiccation, excess moisture, poor potassium fertility, late nitrogen applications, and physical damage. |
Prevention Strategies | Avoid late nitrogen applications, maintain proper soil moisture, improve drainage, minimize traffic on frosted turf, and select resilient turfgrass. |
Turfgrass Susceptibility | Turfgrass susceptibility is influenced by shade, drainage, irrigation, thatch levels, and species-specific cold tolerance. |
Best Turfgrass Choices | Zoysiagrass and Bermudagrass are most resilient; Centipedegrass has moderate tolerance; St. Augustinegrass is highly vulnerable. |
Final Tips | Maintain proper watering, ensure good drainage, avoid excessive fertilization in late fall, and reduce foot traffic on frozen lawns. |
What is Winter Kill in Warm-Season Turf?
Winter kill, also known as cold-weather injury, happens when freezing temperatures damage turfgrass cells, disrupting their ability to function. The result? Large brown patches that stand out in an otherwise green lawn. This issue is especially common in warm-season grasses like:
- Centipedegrass
- St. Augustinegrass
- Bermudagrass
- Zoysiagrass
These grasses are most vulnerable during the fall transition and when coming out of dormancy in late winter or early spring. If not properly cared for, winter kill can leave you with dead turf that won’t recover when temperatures rise.
Key Causes of Winter Kill and Prevention Tips
Several factors contribute to winter kill. Luckily, there are steps you can take to reduce the risk.
1. Direct Low-Temperature Exposure
When temperatures drop below 23°F, ice crystals form inside turfgrass cells, damaging tissue and causing dead patches. These areas may appear matted and develop an unpleasant odor as they decompose.
How to Prevent It:
- Avoid late-season nitrogen applications that promote tender growth.
- Reduce overwatering in the fall so the turf can harden off naturally.
- Ensure gradual exposure to frost to help turf adapt.
2. Winter Desiccation
Even dormant grass needs some moisture. Dry winter winds and frozen soil can prevent turf from absorbing water, leading to dehydration and winter damage.
How to Prevent It:
- Water your lawn during dry winter periods, especially in exposed or windy areas.
- Maintain proper soil moisture without overwatering.
3. Excess Moisture and Poor Drainage
Too much water can be just as harmful as too little. In areas with poor drainage, water can freeze in the soil, damaging turfgrass cells and leading to winter kill.
How to Prevent It:
- Improve drainage lawn aeration, topdressing, and proper grading.
- Monitor shaded areas where water tends to collect.
4. Poor Potassium Fertility
Potassium strengthens turfgrass by regulating water movement and reinforcing cell walls. It also lowers the freezing point inside plant cells, improving cold resistance.
How to Prevent It:
- Conduct a soil test and adjust potassium levels during the growing season.
- Apply a potassium-rich fertilizer before winter to improve turf resilience.
5. Late-Season Nitrogen Applications
Applying nitrogen too late encourages weak, tender growth that drains energy reserves. This makes the turf more vulnerable to freezing temperatures.
How to Prevent It:
- Focus on early-season fertilization for strong, healthy turf.
- Avoid nitrogen applications in the late fall to prevent winter kill.
6. Physical Damage During Frost
Frozen turfgrass is brittle. Walking, driving, or placing heavy equipment on frozen grass can break the blades, leading to visible damage in spring.
How to Prevent It:
- Minimize foot traffic on frosted turf.
- Avoid using vehicles or heavy equipment on frozen grass.
Factors That Increase Susceptibility to Winter Kill
Some lawns are naturally more prone to winter damage than others. If you want to reduce the risk, consider these key factors:
- Shade: Limited sunlight weakens turf, reducing its ability to harden off before winter.
- Drainage Issues: Poor drainage increases the risk of freezing damage, especially in compacted or over-irrigated areas.
- Improper Irrigation: Excess moisture heightens cold stress, while too little causes desiccation.
- Thatch Build-Up: Thick thatch layers can insulate the crown of the grass, increasing moisture retention and susceptibility to freeze damage.
- Turfgrass Type: Some warm-season grasses handle winter stress better than others.
Best Warm-Season Turfgrass for Winter Resilience
The type of turfgrass you choose makes a big difference in how well your lawn withstands cold temperatures. Some species recover better than others due to their natural growth patterns.
Ranking Warm-Season Turfgrass by Cold Tolerance
- Zoysiagrass – Excellent Cold Tolerance: Slow-growing but highly resilient to winter stress.
- Bermudagrass – Medium to Excellent Cold Tolerance: Durable and sun-loving, with improved cultivars offering greater cold resistance.
- Centipedegrass – Medium Cold Tolerance: Low-maintenance but more vulnerable to cold, especially in shaded areas.
- St. Augustinegrass – Poor Cold Tolerance: Thrives in shade but suffers severe damage in freezing conditions.
Why Choosing the Right Turfgrass Matters
If you live in an area prone to winter kill, selecting the right turfgrass can prevent future headaches. Consider these key factors:
- Rhizomatous grasses (like Bermudagrass and Zoysiagrass) regenerate more easily after winter damage.
- Shade tolerance is crucial—St. Augustinegrass does well in low light but struggles in cold weather.
- Drainage and soil conditions should match the needs of your chosen turfgrass.
For expert recommendations, consult a lawn care professional to determine the best turfgrass for your region and property.
Final Tips to Reduce Winter Stress
Want to keep your lawn looking great year-round? Follow these essential tips:
- Choose a cold-tolerant turfgrass species suited to your region.
- Maintain proper soil moisture to prevent desiccation.
- Improve drainage to avoid standing water and crown hydration injuries.
- Conduct soil tests and adjust potassium levels as needed.
- Avoid late-season nitrogen applications that encourage weak growth.
- Minimize foot traffic on frosted or frozen turf.
Winter kill in warm-season turf is a serious problem, but with proper care, you can reduce the risk and keep your lawn healthy. By understanding the causes of cold damage and taking preventive steps, you can ensure your turf bounces back strong in the spring.
Next Steps:
Now that you know how to protect your lawn from winter kill, the next step is learning about winter watering. Proper irrigation prevents desiccation, while avoiding overwatering helps reduce crown hydration injuries.
Read our last article on winter watering for warm-season turf to get expert tips on keeping your lawn hydrated without increasing cold stress.