Knowing when to fertilize lawn in Southern California is the key to keeping it green and healthy all year. Our unique climate means your lawn care schedule is different from most other parts of the country. Get the timing right, and you’ll have a lush, resilient turf. Get it wrong, and you might waste effort or even harm your grass.
This guide will walk you through the best schedule for both warm-season and cool-season grasses. We’ll cover what products to use and how to apply them correctly. Let’s get your lawn looking its absolute best.
When To Fertilize Lawn In Southern California
The golden rule for Southern California is to fertilize during your lawn’s active growth periods. This is when the grass can actually use the nutrients to grow strong roots and blades. For most lawns here, that means late spring through early fall.
However, the exact months depend heavily on what type of grass you have. Southern California gardens often feature a mix, so identifying your grass is the essential first step.
Understanding Your Grass Type
Your fertilization schedule is entirely dictated by whether you have warm-season or cool-season grass. Here’s how to tell the difference:
- Warm-Season Grasses: These thrive in heat and go dormant (turn brown) in winter. They grow actively from late spring to early fall. Common types in SoCal include:
- Bermuda Grass
- St. Augustine Grass
- Zoysia Grass
- Kikuyu Grass
- Cool-Season Grasses: These prefer milder temperatures and struggle in peak summer heat. They grow most actively in spring and fall. Common types include:
- Tall Fescue (very common)
- Kentucky Bluegrass
- Perennial Ryegrass
The Ideal Fertilization Schedule
Now, let’s break down the calendar by grass type. This is your core roadmap for the year.
For Warm-Season Lawns
Feed your warm-season lawn when it wakes up from winter dormancy and is actively growing. A typical schedule involves 3-4 applications.
- Late Spring (April-May): Apply the first feeding as the weather consistently warms and your grass begins to green up. This gives it a strong start.
- Early Summer (June): A second application supports vigorous growth as temperatures rise.
- Late Summer (August): This feeding helps the lawn recover from summer stress and stay green.
- Early Fall (September): A final, lighter application can help with winter hardiness. Avoid fertilizing to late in the fall, as it can promote tender new growth that frost might damage.
For Cool-Season Lawns
Cool-season grasses need their nutrients when the weather is mild. The most important feedings are in the fall and spring.
- Early Fall (Late September – October): This is the most important fertilization of the year. It strengthens roots for the winter and promotes dense growth.
- Late Fall (November): A lighter application can provide nutrients for root growth through the winter.
- Spring (March-April): Feed as growth resumes to support the lawn before summer heat arrives.
- Avoid Summer Fertilizing: Do not fertilize cool-season grasses in the heat of summer (June-August). It stresses the grass and can promote disease.
Choosing the Right Fertilizer
Walking down the fertilizer aisle can be confusing. Here’s what to look for:
- N-P-K Ratio: This is the three-number code on the bag (e.g., 16-4-8). It stands for Nitrogen (N), Phosphorus (P), and Potassium (K). For established lawns, a higher first number (Nitrogen) is key for green leaf growth.
- Slow-Release vs. Quick-Release: In Southern California, slow-release nitrogen is highly recommended. It feeds the lawn gradually over 6-8 weeks, preventing a surge of weak growth and reducing the risk of burning the grass. It’s also better for our environment.
- Specialty Blends: Consider a “weed and feed” product only if you have a significant weed problem, and ensure it’s appropriate for your grass type. Otherwise, stick with a regular lawn fertilizer.
How to Apply Fertilizer Correctly
Proper application ensures your lawn gets the benifit without waste or damage. Follow these steps:
- Mow: Mow your lawn a day or two before you plan to fertilize.
- Water: Water your lawn deeply 1-2 days before applying fertilizer. A moist (not soggy) soil is ideal.
- Calibrate Your Spreader: Whether using a broadcast or drop spreader, set it to the rate recommended on the fertilizer bag. This prevents over- or under-application.
- Apply Methodically: Walk at a steady pace, slightly overlapping your passes to ensure even coverage. Fertilizer stripes or missed spots are often caused by uneven walking speed or poor overlap.
- Water Deeply Again: After applying, water the lawn lightly. This helps wash the fertilizer granules off the grass blades and into the soil. This step is crucial to prevent burning.
Important Seasonal Lawn Care Tips
Fertilizing is just one part of the puzzle. Pair it with these practices for a truly healthy lawn.
Spring
Aerate if your soil is compacted. This allows water, air, and fertilizer to reach the roots. It’s also the best time to overseed thin cool-season lawns or address bare patches.
Summer
Water deeply and infrequently, early in the morning. Adjust your mower to a higher setting; taller grass shades the soil, conserves moisture, and resists weeds better. Watch for signs of fungal disease in humid areas.
Fall
This is prime time for core aeration and overseeding for cool-season grasses. Continue to mow as needed, and gradually reduce watering frequency as temperatures drop. Rake leaves promptly so they don’t smother the grass.
Winter
Reduce watering significantly. For warm-season lawns that are dormant, it’s okay to let them be brown. Avoid heavy traffic on frosty grass, as the blades are brittle and can be damaged easily.
Common Mistakes to Avoid
Even experienced gardeners can make a few errors. Here’s what to steer clear of:
- Fertilizing at the Wrong Time: The biggest mistake is feeding during dormancy or summer stress (for cool-season grass). The lawn can’t use the nutrients, and they often just run off or pollute waterways.
- Over-Fertilizing: More is not better. It can burn your lawn, promote excessive thatch, and lead to polluted runoff. Stick to the schedule and the bag’s rate.
- Ignoring Soil Health: Consider a soil test every few years. It can reveal pH imbalances or specific nutrient deficiencies that general fertilizer won’t fix.
- Watering Improperly After Feeding: Forgetting to water in the fertilizer can lead to burning. Watering too much can wash it away before the roots get it.
Frequently Asked Questions (FAQ)
Can I fertilize my lawn year-round in Southern California?
No, you should not. Fertilizing during a lawn’s dormant period (winter for warm-season, peak summer for cool-season) is ineffective and can harm the environment. Stick to the active growth cycles.
What is the best month to start fertilizing in spring?
For warm-season grasses, aim for late April or May, when soil temperatures are consistently above 65°F. For cool-season grasses, early to mid-March is usually ideal.
Is fall fertilization really necessary?
Yes, especially for cool-season grasses. Fall feeding is critical for root development and winter hardiness. For warm-season lawns, an early fall feeding helps maintain color and health.
How often should I fertilize my lawn?
Most Southern California lawns do well with 3-4 feedings per year. Warm-season grasses often need 4, while cool-season grasses typically thrive on 3 (with a strong focus on fall).
Should I fertilize before or after rain?
Avoid applying fertilizer right before a heavy rainstorm, as it can be washed away. If a light rain is expected, it’s generally fine. The best practice is to apply to moist soil, then water it in yourself with a light irrigation.
Can I use the same fertilizer for all grass types?
While a general lawn fertilizer often works, optimal results come from using a product formulated for your specific grass type (e.g., “Bermuda Grass Food”). Always check the label for compatibility.
By following this tailored schedule and tips, you’ll give your Southern California lawn exactly what it needs, exactly when it needs it. Consistent, thoughtful care is the secret to a beautiful green yard that enhances your home.