If you want a thick, green, and resilient lawn, knowing when do you fertilize zoysia grass is the most important step. Getting the timing right makes all the difference between a good lawn and a great one. This guide will walk you through the exact schedule and methods for optimal growth.
Zoysia is a warm-season grass known for its drought tolerance and dense growth. It thrives in heat but goes dormant and turns brown after the first hard frost. Your fertilization schedule must support this natural cycle. Feeding it at the wrong time can do more harm than good.
When Do You Fertilize Zoysia Grass
This is your core schedule. Zoysia grass needs the majority of its nutrients during its active growing season, which is late spring through summer. The goal is to fuel growth when it can actually use the food.
The Ideal Fertilization Timeline
Follow this simple timeline for best results. Straying too early or too late can encourage weeds or winter injury.
- Late Spring (Greening-Up): Apply your first fertilizer only after the grass has fully “greened up.” This is usually when soil temperatures consistently reach 70°F. For most, this is late May or early June. Feeding too early can feed winter weeds and stress the grass.
- Early Summer: About 6-8 weeks after the first application, provide a second feeding. This is typically in early to mid-July and supports the grass during peak growth and heat stress.
- Late Summer (Optional): A third application can be made in early August, especially if your lawn looks pale or growth has slowed. Avoid fertilizing too late in the season.
- Early Fall (Special Feed): This is not a nitrogen feed. Apply a potassium-only or “winterizer” fertilizer (like 0-0-60 or a similar high-potassium mix) around September. This strengthens the grass roots for winter dormancy and improves spring green-up. Do not use nitrogen here.
Why Timing is Everything
Fertilizing at the correct time prevents several problems. Early spring feeding invigorates weeds like crabgrass before the zoysia can compete. Fall nitrogen applications can force tender new growth that is easily killed by frost, damaging the entire plant. The late-season potassium boost, however, is crucial for cold hardiness.
Signs Your Zoysia is Ready for Fertilizer
Don’t just go by the calendar. Watch your lawn. It should be completely out of dormancy, with no brown patches from frost. You should have mowed it at least twice. This ensures the grass is actively growing and can immediatly use the nutrients.
Choosing the Right Fertilizer
Not all lawn fertilizers are created equal. Using the wrong type can lead to excessive thatch or weak growth.
- NPK Ratio: Look for a balanced or slightly nitrogen-heavy slow-release granular fertilizer. A ratio like 15-0-15, 16-4-8, or 15-5-10 is often ideal for zoysia. The slow-release formula feeds the grass gradually over 6-8 weeks.
- Nitrogen (N): Promotes green leaf and blade growth. Zoysia needs about 2 to 4 pounds of actual nitrogen per 1,000 square feet per growing season. Split this across your 2-3 applications.
- Phosphorus (P): Supports root development. Most established lawns have sufficient phosphorus. A soil test can tell you if you need it.
- Potassium (K): The most important nutrient for zoysia. It enhances disease resistance, drought tolerance, and winter hardiness. That’s why the fall potassium application is non-negotiable.
The Critical Role of a Soil Test
Before you buy any fertilizer, get a soil test. Your local cooperative extension office offers kits. This test will tell you your soil’s pH and exact nutrient levels. Zoysia prefers a pH between 6.0 and 6.5. If the pH is off, nutrients become locked and unavailable to the grass, no matter how much you fertilize. The test will give you precise fertilizer recommendations.
Step-by-Step Fertilizer Application
Doing it correctly ensures even coverage and prevents burning your lawn.
- Mow: Mow your lawn a day or two before applying fertilizer. Collect the clippings to ensure the granules reach the soil.
- Calibrate Your Spreader: This step is often skipped but is vital. Set your broadcast or drop spreader to the rate listed on the fertilizer bag. Apply half the product walking north-south, and the other half walking east-west. This criss-cross pattern prevents streaks and missed spots.
- Water Lightly: After application, lightly water the lawn. This helps wash the granules off the grass blades and into the soil where they can start to break down. You don’t need to soak it, just a quick 10-15 minute sprinkle.
Common Fertilization Mistakes to Avoid
Even experienced gardeners can make these errors. Being aware of them protects your lawn.
- Fertilizing Too Early in Spring: This is the number one mistake. It feeds weeds and wastes product.
- Using Weed & Feed at the Wrong Time: Weed & Feed products are designed for pre-emergent weed control in early spring, which is before zoysia should get nitrogen. They are rarely a good fit for zoysia’s schedule.
- Over-fertilizing: More is not better. Excess nitrogen leads to rapid growth, excessive thatch buildup, increased mowing, and greater suscetibility to disease and drought stress.
- Ignoring the Soil Test: Guessing your soil’s needs is a waste of money and can harm your lawn’s long-term health.
Seasonal Care Tips for Optimal Growth
Fertilizer works best when combined with proper overall lawn care. Here’s how to support your feeding schedule.
Spring Care
Wait for green-up. Mow at the recommended height of 1.5 to 2.5 inches. Dethatch only if the thatch layer is over 1/2 inch thick. Apply pre-emergent herbicide for crabgrass if needed, but seperately from your fertilizer.
Summer Care
This is zoysia’s prime time. Mow regularly, never removing more than 1/3 of the blade height. Water deeply but infrequently, providing about 1 inch of water per week, including rainfall. This encourages deep roots. Watch for signs of stress, but zoysia’s brown patches in summer heat often just indicate dormancy and will green up after rain.
Fall and Winter Preparation
Continue mowing as long as the grass is growing. After the final mowing, apply your potassium-only winterizer fertilizer. Keep leaves raked off the lawn to prevent matting and disease. In winter, the grass is dormant and brown—avoid walking on it when its frosted to prevent crown damage.
FAQ: Your Zoysia Fertilization Questions Answered
Can I fertilize zoysia in the fall?
Yes, but only with a potassium (potash) fertilizer, not a nitrogen-based one. The fall potassium application is for root strength and winter survival, not top growth.
What is the best fertilizer for zoysia grass?
The best fertilizer is one that matches your soil test results. Generally, a slow-release granular fertilizer with an NPK ratio like 15-0-15 or 16-4-8 applied during the growing season, followed by a 0-0-60 in early fall, works excellently.
How often should you feed zoysia?
Most lawns thrive on 2-3 applications of nitrogen fertilizer during the active growing season (late spring to late summer), plus one potassium application in early fall. Over-feeding can cause problems.
Is it too late to fertilize zoysia in August?
An application in early August is usually fine. However, you should avoid applying nitrogen fertilizer within 6-8 weeks of your area’s expected first frost date, as it can promote vulnerable new growth.
Why is my zoysia not turning green after fertilizing?
If you fertilized while it was still dormant, the nutrients may have washed away or fed weeds. Ensure the grass is fully green before feeding. Also, check soil pH with a test; acidic or alkaline soil can lock out nutrients even after fertilization.
Should you water zoysia after fertilizing?
Yes, a light watering is recommended. It moves the fertilizer granules into the soil and prevents them from sitting on the grass blades, which could cause burning in the sun. You don’t need a deep watering, just enough to rinse the soil surface.
Following this precise schedule for when do you fertilize zoysia grass sets the foundation for a healthy lawn. Remember, patience in spring is key—wait for that full green-up. Combine your timely feedings with proper mowing, watering, and a fall potassium boost. With this care, your zoysia will develop the deep roots and dense turf it’s famous for, giving you a beautiful, resilient lawn that can withstand summer heat and bounce back vibrantly each spring.