When To Fertilize Zoysia

Knowing when to fertilize zoysia is the single most important factor for a thick, green, and healthy lawn. If you get the timing wrong, you can waste effort or even harm your grass. This guide will walk you through the optimal schedule for your climate and soil, ensuring your zoysia gets exactly what it needs, exactly when it needs it.

Zoysia grass is a warm-season turf known for its drought tolerance and dense growth. But to achieve that lush carpet, it requires targeted nutrition at key moments in its growing cycle. Fertilizing at the wrong time can lead to weak roots, increased thatch, and greater susceptibility to winter damage or disease. Let’s break down the ideal calendar for your lawn care.

The core principle for fertilizing zoysia is to feed it during its active growth period and leave it alone when it’s dormant. For almost all zoysia varieties, this means a fertilization window from late spring through late summer.

Understanding Zoysia’s Growth Cycle

Zoysia thrives in warm soil and warm air temperatures. It greens up in late spring, grows vigorously in the summer heat, and begins to go dormant after the first hard frost in fall. Your fertilizer schedule should mirror this rhythm perfectly.

Applying fertilizer too early in spring can force tender new growth that a late frost might damage. Fertilizing too late in fall can prevent the grass from hardening off for winter, making it vulnerable to cold injury. The goal is to support growth, not disrupt the grass’s natural dormancy cycles.

The Optimal Fertilization Schedule

Here is a general timeline for when to fertilize your zoysia lawn. Remember, your local climate and soil test results are the final authority.

1. Late Spring (Greening-Up Phase)

Apply your first fertilizer when the lawn is fully green and has been mowed at least twice. This is typically when soil temperatures consistently reach 65-70°F. For most, this is late May or early June.

Why: This initial feeding provides nutrients for the initial surge of growth.
What to Use: A balanced, slow-release nitrogen fertilizer is ideal.

2. Early to Mid Summer (Peak Growth)

This is the main feeding time. Plan for 1-2 applications between June and July.

Why: This supports the grass during it’s most active period, encouraging density and color.
What to Use: Continue with a slow-release nitrogen source to avoid burning the lawn and to provide steady nutrition.

3. Late Summer (Final Application)

Your last fertilizer application should be done no later than 6-8 weeks before your area’s average first frost date. For many, this is early August.

Why: A final feeding helps the grass store carbohydrates for the winter and improves its green-up the following spring.
What to Use: You may use a balanced fertilizer or one slightly lower in nitrogen but with potassium to promote winter hardiness.

4. Fall and Winter: The Off-Season

Do not fertilize zoysia in the fall or winter. The grass is slowing down or is completely dormant. Fertilizer applied now will not be used by the grass and can pollute waterways or feed winter weeds.

Step-by-Step: How to Apply Fertilizer Correctly

Timing is only half the battle. Proper application ensures the fertilizer benefits the lawn without causing problems.

Test Your Soil First. A soil test every 2-3 years tells you exactly what nutrients your lawn lacks. It prevents over-application and saves you money.
Choose the Right Product. Look for a lawn fertilizer with a significant portion of its nitrogen in a slow-release form (often listed as WIN, SCU, or polymer-coated). A ratio like 15-0-15 or 16-4-8 is often good for zoysia, but follow soil test recommendations.
Calibrate Your Spreader. Whether you use a broadcast or drop spreader, set it to the rate listed on the fertilizer bag. This ensures even coverage and prevents striping or burning.
Apply to Dry Grass. Fertilize when the grass blades are dry to prevent them from sticking to the foliage and causing burn.
Water It In. Lightly water the lawn after application. This washes the granules off the grass blades and into the soil, where they can start to work. About a quarter-inch of water is sufficient.

Regional Adjustments to the Schedule

Your location plays a huge role in fine-tuning when to fertilize.

Transition Zone & Northern States

If you live where winters are cold, your window is shorter. Stick strictly to the late spring to early August schedule. Avoid any fall fertilization to ensure proper dormancy and prevent winterkill.

Southern & Gulf Coast States

With a longer growing season, you may fit in an extra application. However, the core rule remains: stop fertilizing at least 6-8 weeks before your expected first frost, even if the grass still looks green. High humidity in these areas also increases disease risk, so avoid excess nitrogen.

Common Mistakes to Avoid

Even with good intentions, its easy to make errors. Here are the big ones to steer clear of.

Fertilizing Too Early in Spring: This is the most common error. Patience is key. Wait for consistent green-up.
Using Quick-Release Fertilizers: They cause a rapid flush of growth that is unsustainable and increases mowing and thatch buildup. Slow-release is always better for zoysia.
Over-Fertilizing: More is not better. Zoysia is naturally slow-growing and requires less nitrogen than grasses like Bermuda. Over-feeding leads to thatch, disease, and water pollution.
Ignoring Soil pH: Zoysia prefers a slightly acidic soil pH (6.0-6.5). If your pH is too low or too high, the grass can’t absorb nutrients effectively, making your fertilizer useless.

Special Considerations: New Sod, Plugs, and Seed

Newly established zoysia has different needs.

For sod or plugs, wait 30-45 days after planting before applying the first fertilizer. This allows the roots to establish themselves in the soil. Use a starter fertilizer high in phosphorus (the middle number) to promote root growth, unless your soil test shows high phosphorus levels.

For seeded lawns, follow the product instructions, but generally, a light application of starter fertilizer at seeding and another 6 weeks later is effective. Keep the seedbed moist during germination, which can be slow for zoysia.

FAQ: Your Fertilizer Questions Answered

Can I fertilize zoysia in the fall?

No. Fertilizing zoysia in the fall is not recommended. It can disrupt the dormancy process and make the lawn more susceptible to winter cold damage. The last feeding should be in late summer.

What is the best fertilizer for zoysia grass?

The best fertilizer is one that matches your soil test results. Generally, a balanced slow-release fertilizer with a 1-0-1 or 1-0.5-1 N-P-K ratio (like 15-0-15 or 16-4-8) works well. The key is the slow-release nitrogen.

How many times a year should you fertilize zoysia?

Most established zoysia lawns do well with 2-3 applications per year: one in late spring, one in early summer, and a final one in late summer. In poorer soils, a third application might be beneficial, but in rich soils, sometimes two is enough.

Should you water zoysia after fertilizing?

Yes, you should always water in granular fertilizer with about 1/4 inch of water. This moves the nutrients into the soil and prevents the granules from sitting on the grass blades, which can cause burn.

Is it okay to fertilize zoysia when its dormant and brown?

Absolutely not. Fertilizing dormant zoysia provides no benefit to the grass. The roots are not actively taking up nutrients, so the fertilizer will either sit there or run off, potentially harming the environment.

Putting It All Together

The perfect schedule for when to fertilize zoysia boils down to a few simple rules. Always wait for full green-up in spring. Use a slow-release fertilizer based on a soil test. Make your last application in late summer, well before frost. And never fertilize during dormancy.

By following this natural cycle, you support your zoysia’s strength and resilience. You’ll be rewarded with a dense, weed-resistant turf that can handle summer heat with deep roots and vibrant color. Remember, a healthy lawn starts with what and when you feed it. Now you have the knowledge to get it right.