How to Keep Your Lawn Green in San Diego Through Fall and Winter

San Diego’s fall and winter bring milder temperatures and less rain, but that doesn’t mean your lawn has to lose its lush, green vibrancy. With a few strategic steps, you can keep your lawn looking its best all season long, even as it cools down.

1. Adjust Your Watering Schedule

San Diego's cooler fall and winter temperatures mean less evaporation, so your lawn needs less water. Start by reducing the frequency but continue with deep watering to ensure roots stay hydrated. Aim to water in the morning to minimize fungal issues that can arise in damp overnight conditions.

Tip: Set your irrigation system to water less often but deeply to encourage root growth and prevent runoff.

2. Aerate and Overseed for a Healthy Lawn

Early fall is a great time to aerate your lawn, especially if it gets a lot of foot traffic. Aerating helps break up compacted soil, allowing water, oxygen, and nutrients to penetrate deeper. Follow aeration by overseeding with a cool-season grass variety, like ryegrass, which stays green throughout the winter.

Tip: Overseeding with ryegrass not only keeps your lawn green but also thickens it, helping to crowd out winter weeds.

3. Feed Your Lawn with Seasonal Fertilizer

Your lawn may need less fertilizer in the fall and winter, but it’s still important to keep it nourished. Apply a slow-release, balanced fertilizer high in potassium, which strengthens roots and improves your lawn’s resistance to cold, drought, and diseases. Avoid high-nitrogen fertilizers at this time, as they encourage growth rather than preparing the grass for dormancy.

Tip: Fertilizing before a rainfall will help nutrients soak deep into the soil, but avoid fertilizing just before a heavy rain, which could wash nutrients away.

4. Raise Your Mower Height

Grass grows slower in the cooler months, so you can reduce mowing frequency. When you do mow, keep the grass a bit longer—around 2.5-3 inches for most varieties. Taller grass helps shade the soil, reducing moisture loss and creating an environment less inviting to weeds.

Tip: Don’t remove more than one-third of the grass blade at once, as cutting too short can stress your lawn.

5. Control Weeds Before They Spread

With less active growth in cooler seasons, weeds like clover and dandelions can take hold. A pre-emergent herbicide applied in early fall will prevent winter weeds from sprouting. For existing weeds, spot-treat as needed, but avoid using weed killers too late in the season, as they can damage your lawn’s winter health.

Tip: Choose a selective herbicide designed for winter weeds, or remove weeds manually if they’re minimal.

6. Mulch Leaves and Keep Your Lawn Clear

Fallen leaves may look picturesque, but they can block sunlight and trap moisture against your lawn, inviting fungal growth. Rather than raking them away, try mulching the leaves with a mower to add organic matter back into the soil. 

Tip: A thin layer of mulched leaves acts like a natural fertilizer for your lawn, but don’t let thick layers accumulate, as they can smother the grass.

7. Prevent Disease and Manage Pests

Cooler, wetter weather can increase the risk of fungal diseases like brown patch. To prevent this, ensure your lawn is properly drained and avoid overwatering. If you notice brown or bare patches, treat them with a fungicide or call a professional for guidance. Additionally, pests like gophers can still be active in winter, so monitor for signs of burrowing and take action as needed.

Tip: Early intervention is key, act quickly at the first signs of disease or pest damage to keep issues from spreading.

Keeping your lawn green and healthy in San Diego’s fall and winter requires a few simple adjustments, but with regular care, you can enjoy a lush landscape all year round. By following these tips, you'll ensure your lawn stays resilient and ready for the warmer months ahead.