After months of cold temperatures and dormancy, your lawn is waking up hungry—and the way you feed it in spring can make or break your grass for the entire year. Fertilizing at the right time gives your lawn the boost it needs to grow thick, green, and resilient, but mistiming it can lead to weak growth, thatch buildup, or even burnt grass.
So, when is the perfect time to fertilize? Should you do it in early spring, late spring, or somewhere in between? And what type of fertilizer works best?
In this guide, we’ll break down exactly when and how to fertilize your lawn in spring to maximize growth while avoiding common mistakes. Whether you’re a seasoned lawn enthusiast or just starting out, these tips will help you get healthier, greener grass that thrives all season long.
Let’s dive in and give your lawn the best spring feeding possible!
Why Spring Fertilization Is Essential for a Healthy Lawn
When Is the Best Time to Fertilize Your Lawn in Spring?
Choosing the Right Fertilizer for Spring Feeding
How to Fertilize Your Lawn Properly in Spring
Common Fertilization Mistakes to Avoid
Should You Combine Fertilizer with Other Spring Lawn Treatments?
Why Spring Fertilization Is Essential for a Healthy Lawn
As winter fades and temperatures rise, your lawn is gearing up for its most important growth phase of the year. After months of dormancy, the grass needs a fresh supply of nutrients to develop strong roots, vibrant green blades, and a thick, healthy appearance.
Spring fertilization isn’t just about making your lawn look good—it’s about giving it the right foundation for the entire growing season. When done correctly, it helps grass:
- Recover from winter stress – Cold weather and frost can weaken grassroots. Fertilizer replenishes essential nutrients.
- Grow thicker and greener – Nitrogen-rich fertilizers promote lush, green growth.
- Develop deeper, stronger roots – A well-fed lawn resists drought and disease better.
- Choke out weeds before they spread – A thick lawn leaves little room for weeds to take over.
When Is the Best Time to Fertilize Your Lawn in Spring?
Timing is everything when it comes to fertilizing. Too early, and your lawn might not absorb the nutrients properly. Too late, and you risk weak summer growth.
Fertilizing too early (before your grass wakes up) can:
- Encourage weak top growth instead of deep root development.
- Waste fertilizer because dormant grass won’t fully absorb the nutrients.
- Promote weeds like crabgrass, which thrive on early nitrogen.
Fertilizing too late (late spring or early summer) can:
- Make your lawn more vulnerable to drought and heat damage.
- Overstimulate growth right before summer stress hits.
The best time to fertilize depends on soil temperature, grass type, and your local climate. Here’s how to get it right.
Understanding Soil Temperature vs. Calendar-Based Fertilization
Many homeowners rely on the calendar to determine when to fertilize, but soil temperature is a much better indicator. Grass starts actively growing when soil temperatures reach around 55°F (13°C) at a depth of 2 to 4 inches. This is usually when lilacs begin to bloom and grass starts growing noticeably.
A simple way to check soil temperature is by using a soil thermometer or by looking up soil temperature data for your area online.
When to Fertilize Based on Grass Type
Cool-season grasses (Kentucky bluegrass, fescue, ryegrass):
- Best time: Early to mid-spring, when soil reaches 55–60°F (13–16°C).
- Why: These grasses grow actively in cool weather and benefit from an early-season nutrient boost.
Warm-season grasses (Bermuda, Zoysia, St. Augustine, centipede grass):
- Best time: Late spring, when soil warms up to 65–70°F (18–21°C).
- Why: Warm-season grasses thrive in hot weather, so early fertilization can be wasted if applied too soon.
Signs Your Lawn Is Ready for Fertilizer
If you are unsure when to apply fertilizer, look for these natural cues:
- Your grass is growing and needs mowing more frequently.
- Lilacs or forsythia are blooming, signalling warmer soil.
- Soil temperature reaches 55°F or higher, indicating active root growth.
By fertilizing at the right time, you ensure that your lawn gets the nutrients it needs to grow strong, green, and resilient throughout the season.
In the next section, we’ll explore how to choose the best fertilizer for spring feeding.
Choosing the Right Fertilizer for Spring Feeding
Not all fertilizers are created equal, and choosing the right one can make a big difference in how well your lawn responds to its spring feeding. The key is understanding nutrient ratios, fertilizer types, and what your grass actually needs to thrive.
Instead of guessing, a soil test can provide a clear picture of what your lawn is lacking and help you choose the perfect fertilizer formula.
Why a Soil Test Helps You Choose the Best Fertilizer
Before applying fertilizer, a soil test is one of the best ways to ensure you’re giving your lawn exactly what it needs—without overloading it with unnecessary nutrients. Many homeowners blindly apply fertilizers without knowing what’s already in their soil, but a soil test removes the guesswork and helps you get the best results.
What a Soil Test Tells You
A professional or DIY soil test will measure key factors that affect your lawn’s health, including:
- Nutrient Levels (N-P-K Ratio)
- Tells you whether your soil has enough nitrogen (N), phosphorus (P), and potassium (K) for healthy grass growth.
- Helps you determine the right fertilizer formula instead of choosing one at random.
- Soil pH (Acidity or Alkalinity)
- Most grasses thrive in a pH range of 6.0 to 7.0 (slightly acidic to neutral).
- If the pH is too low (acidic), adding lime can help.
- If the pH is too high (alkaline), applying sulfur or gypsum can correct it.
- Organic Matter and Soil Health
- A good level of organic matter improves soil structure and moisture retention.
- Low organic matter may indicate a need for compost or organic fertilizers to enrich the soil.
- Compaction and Drainage Issues
- Poor drainage or compacted soil can make it harder for roots to absorb nutrients.
- If compaction is an issue, aerating before fertilizing can help.
How to Perform a Soil Test
There are two ways to test your soil:
Professional Lab Test – Send a soil sample to your local extension office or an online lab for a detailed nutrient breakdown. Results usually include custom fertilization recommendations based on your lawn’s needs.
DIY Soil Test Kit – Available at garden centers, these kits give basic nutrient and pH readings but may not be as detailed as a lab test.
Understanding N-P-K Ratios and What Your Lawn Needs
If a soil test shows your lawn is low on specific nutrients, you can choose a fertilizer with the right balance of N-P-K (Nitrogen, Phosphorus, and Potassium) to correct the deficiency.
Fertilizer bags display three numbers, known as the N-P-K ratio, which represents the percentage of:
- Nitrogen (N) – Promotes lush, green top growth.
- Phosphorus (P) – Supports strong root development.
- Potassium (K) – Enhances stress resistance and disease prevention.
For spring, most lawns benefit from a fertilizer with a higher nitrogen content to encourage healthy green growth. A common spring formula is 20-5-10, meaning 20% nitrogen, 5% phosphorus, and 10% potassium. However, the right ratio depends on your soil’s condition, which is why a soil test is the best way to determine your lawn’s exact needs.
Here’s how to match your fertilizer to your soil test results:
- Low Nitrogen (N)? Use a fertilizer with a higher first number (like 20-5-10) to boost green growth.
- Low Phosphorus (P)? Choose a fertilizer with a higher second number to strengthen root development.
- Low Potassium (K)? Pick a fertilizer with a higher third number to improve drought and disease resistance.
- pH Imbalance? Adjust with lime (for acidic soil) or sulfur (for alkaline soil) before applying fertilizer.
Slow-Release vs. Quick-Release Fertilizers
Choosing between slow-release and quick-release fertilizers affects how your lawn absorbs nutrients:
- Slow-release fertilizer
Provides steady nutrients over time
Reduces the risk of lawn burn
Requires fewer applications - Quick-release fertilizer
Offers an immediate nutrient boost
Works well for a struggling or thin lawn
Requires careful application to avoid over-fertilization
For most homeowners, slow-release fertilizers are the best option because they feed the lawn gradually and promote steady growth without overstimulating the grass. Check local regulations; some states restrict the use of slow-release fertilizers during certain times of the year.
Organic vs. Synthetic Fertilizers: Which Is Better?
Both organic and synthetic fertilizers can provide great results, but they work differently:
- Organic fertilizers (compost, manure, fish emulsion)
Improve soil health and encourage microbial activity
Release nutrients slowly and naturally
Environmentally friendly but take longer to show results - Synthetic fertilizers (granular or liquid chemical formulas)
Provide a fast, targeted nutrient boost
More affordable and widely available
Can cause overgrowth or leaching if not applied correctly
If you want long-term soil health and sustainability, organic options are a great choice. If you need a quick green-up, a balanced synthetic fertilizer may be the better fit.
The Best Way to Choose Your Spring Fertilizer
If you haven’t done a soil test, a balanced fertilizer like 20-5-10 is a good general option for spring feeding. But if you want to maximize your lawn’s health and avoid wasting fertilizer, a soil test is the best way to find the right formula for your grass.
By choosing the right fertilizer based on your lawn’s specific needs, you set the stage for strong, healthy grass that thrives throughout the season.
Next, we’ll go over the step-by-step process of applying fertilizer correctly.
How to Fertilize Your Lawn Properly in Spring
Applying fertilizer the right way is crucial for achieving an even, healthy lawn. If you apply too much in one spot, you risk burning your grass. If you apply too little, your lawn may not get the nutrients it needs. Proper fertilization starts with knowing exactly how much fertilizer to use and using a spreader correctly to distribute it evenly. Follow these steps to ensure you get the best possible results.
Step 1: Measure Your Lawn and Calculate the Right Amount of Fertilizer
Knowing how much fertilizer you need is essential before applying it. Fertilizer bags list an application rate, usually in pounds per one thousand square feet, so you must measure your lawn to determine the amount to use.
To measure your lawn, break it down into simple rectangular or square sections. Multiply the length by the width of each section to get the total square footage. If your lawn has irregular shapes, estimate as best as possible or use an online tool to help.
For example, if your front lawn is fifty feet long and forty feet wide, the total area is two thousand square feet. If the fertilizer you purchased recommends using five pounds per one thousand square feet, you will need ten pounds to cover your entire lawn.
It is important to follow the fertilizer instructions carefully. Using too much can cause excessive growth, thatch buildup, or even lawn burn, while too little may not provide enough nutrients for optimal health.
Step 2: Choose and Adjust the Right Spreader for Even Application
A fertilizer spreader is essential for even coverage. Spreading fertilizer by hand leads to uneven patches, streaky growth, and wasted product. There are two main types of spreaders to consider.
A broadcast or rotary spreader spreads fertilizer in a wide pattern, making it ideal for larger lawns. A drop spreader releases fertilizer directly below the spreader, providing more precision but requiring more passes.
Every spreader has an adjustable setting that controls how much fertilizer is released as you walk. The correct setting for your spreader is listed on the fertilizer bag. If your spreader model is not listed, start with a low setting and make a test pass over a small area before adjusting as needed. The goal is to apply the recommended amount evenly across the entire lawn without excess buildup in any area.
The spreader should be set to release fertilizer at the correct rate so that when you cover the entire lawn, you have used the amount calculated in step one. If you reach the end of your lawn and still have fertilizer left, you may need to adjust the setting to release more. If you run out before finishing, you may need to close the setting slightly to reduce the output.
Step 3: Load the Spreader and Apply Fertilizer Correctly
When loading the spreader, do so over a driveway or a tarp to catch any spills. This prevents excess fertilizer from being dumped in one spot on the lawn, which could cause burning.
Begin walking at a steady pace, making straight passes across the lawn. Apply fertilizer in one direction first, then make a second pass at a right angle to the first. This ensures full coverage without streaks or missed patches. Overlapping slightly with each pass helps prevent gaps, but too much overlap can result in over-fertilization.
Avoid stopping while the spreader is open, as this can release too much fertilizer in one area. If using a broadcast spreader, be mindful that it throws fertilizer beyond the wheels, so avoid applying too close to flower beds or walkways.
Step 4: Water the Lawn to Activate the Fertilizer
After fertilizing, lightly water the lawn to help the nutrients soak into the soil. Granular fertilizers need moisture to begin breaking down and feeding the grass, while some liquid fertilizers require dry conditions for a few hours before watering. Follow the instructions on the fertilizer packaging for the best results.
Avoid applying fertilizer before heavy rain, as excessive water can wash the nutrients away before the grass absorbs them.
Step 5: Maintain Proper Lawn Care After Fertilization
Fertilizing is just one part of spring lawn care. To ensure the best results, mow your lawn regularly, water deeply but infrequently, and consider aerating if your soil is compacted. Proper maintenance will help the fertilizer work more effectively and keep your lawn looking green and healthy throughout the season.
Following these steps, you can apply fertilizer evenly and efficiently, ensuring your grass gets the nutrients it needs to grow strong and vibrant. In the next section, we will look at common fertilization mistakes to avoid.
Common Fertilization Mistakes to Avoid
Fertilizing your lawn in spring is one of the best ways to promote strong, healthy grass, but applying fertilizer incorrectly can do more harm than good. Too much fertilizer can burn your lawn, while too little may not provide enough nutrients. Uneven application can result in patchy growth, and applying at the wrong time may lead to wasted product and weak grass. Here are some of the most common fertilization mistakes and how to avoid them.
Applying Fertilizer Too Early or Too Late
Timing is crucial when fertilizing in spring. Applying fertilizer too early can encourage excessive top growth before roots are ready to support it. This leads to weak, leggy grass that struggles later in the season.
On the other hand, waiting too long can leave your lawn without the nutrients it needs to recover from winter dormancy, leading to slow, thin growth and increased vulnerability to weeds.
How to avoid this mistake:
Use soil temperature as your guide rather than the calendar. Grass is ready for fertilizer when soil temperatures reach around 55°F (13°C). This is typically when grass begins actively growing, and lilacs or forsythia start blooming.
Using the Wrong Type of Fertilizer
Not all fertilizers are created equal, and choosing the wrong one for your lawn can lead to poor results. Some fertilizers contain too much nitrogen, which can promote excessive leaf growth at the expense of strong roots. Others may lack the nutrients your specific soil needs.
How to avoid this mistake:
Perform a soil test before fertilizing to determine which nutrients your lawn actually needs. If a soil test is unavailable, a balanced fertilizer like 20-5-10 is a good general option for spring feeding.
Over-Fertilizing and Burning the Lawn
More fertilizer does not mean better results. Over-applying fertilizer can cause chemical burns, turning grass yellow or brown and weakening its ability to absorb water and nutrients. This is especially common when using quick-release fertilizers or applying fertilizer by hand without a spreader.
How to avoid this mistake:
Measure your lawn area carefully and follow the application rates on the fertilizer bag. Use a good quality spreader to ensure even distribution and never exceed the recommended amount.
Uneven Application Leading to Patchy Growth
Applying fertilizer inconsistently can result in dark green stripes where fertilizer was applied too heavily and pale areas where it was applied too lightly. This can make your lawn look uneven and unhealthy.
How to avoid this mistake:
Use a broadcast or drop spreader and walk at a steady pace while making two passes at right angles for full coverage. Slightly overlap each pass to prevent missed spots but avoid excessive overlap, which can lead to over-fertilization.
Not Watering After Fertilizing
Fertilizer needs water to break down and be absorbed by the soil. Leaving granular fertilizer on dry grass for too long can reduce its effectiveness and increase the risk of lawn burn. However, watering too much can wash away nutrients before they are absorbed.
How to avoid this mistake:
Water the lawn lightly after fertilizing to help nutrients soak into the soil. Avoid fertilizing before heavy rain, as excess water can cause runoff and waste your fertilizer.
Fertilizing Too Frequently or Not Enough
Some homeowners fertilize too often, thinking it will keep their lawn green and lush. In reality, too much fertilization can lead to excessive growth, thatch buildup, and even pest problems. On the other hand, fertilizing too infrequently can leave your lawn weak and nutrient-deficient.
How to avoid this mistake:
Most lawns only need one or two fertilizer applications in spring, depending on grass type and soil conditions. If you plan to fertilize twice, space the applications six to eight weeks apart and choose a slow-release fertilizer to provide steady nutrients.
Ignoring Local Fertilizer Regulations
Some states and municipalities have restrictions on when and how fertilizers can be applied to prevent nutrient runoff into waterways. Certain areas prohibit fertilizing during specific times of the year or require the use of phosphorus-free fertilizers to protect the environment.
How to avoid this mistake:
Check your local regulations before applying fertilizer. If phosphorus is restricted, choose a fertilizer with a zero in the middle number (such as 20-0-10) to comply with regulations.
Should You Combine Fertilizer with Other Lawn Treatments?
Spring is a critical time for lawn care, and many homeowners wonder whether they should combine fertilization with other treatments such as weed control, aeration, or lime application. While some treatments can be applied alongside fertilizer for maximum efficiency, others should be spaced out to prevent negative interactions.
Can You Fertilize and Apply Weed Control at the Same Time?
Many lawn fertilizers come with built-in weed control, often labeled as “Weed & Feed.” These products contain both nutrients for grass growth and herbicides to kill or prevent weeds.
When to use a Weed & Feed product:
- If pre-emergent weed control is needed to prevent crabgrass and broadleaf weeds, apply a pre-emergent Weed & Feed in early spring before weeds germinate.
- If you already have weeds growing, a post-emergent Weed & Feed can help kill existing weeds while feeding the grass.
When NOT to use Weed & Feed:
- If you plan to overseed your lawn, avoid Weed & Feed, as the herbicide can prevent new grass seeds from germinating.
- If your lawn does not have a major weed problem, separate fertilizer and weed control applications may be more effective.
For targeted weed control, applying a standalone herbicide separately from fertilization allows for better timing and more precise treatment.
Can You Aerate and Fertilize at the Same Time?
Aeration and fertilization work well together, especially if your soil is compacted. Aerating before fertilizing allows nutrients to reach deeper into the soil, promoting stronger root growth.
Best approach:
- Aerate first, then fertilize. The small holes created by aeration allow fertilizer and water to penetrate more effectively.
- Overseed after aeration if you are trying to improve lawn density, but avoid Weed & Feed if seeding.
Should You Apply Lime and Fertilizer Together?
Lime is used to adjust soil pH, making it more favorable for grass growth. However, lime and fertilizer should not always be applied at the same time.
Best approach:
- If your soil pH is too low (acidic), lime should be applied before fertilizing to help grass absorb nutrients more efficiently.
- Test your soil first. If your pH is below 6.0, lime is beneficial. If your soil pH is already balanced, lime is unnecessary.
- It is best to wait a few weeks between lime and fertilizer applications to allow the lime to take effect.
What About Fungicides and Insect Control?
- Fungicides: If your lawn is prone to fungal diseases like dollar spot or brown patch, applying a fungicide separately from fertilizer is recommended. Some fertilizers contain too much nitrogen, which can fuel fungal growth.
- Insecticides: If dealing with grubs or lawn pests, consider applying a grub control product before or after fertilization, not at the same time, to ensure effectiveness.
While some treatments, such as aeration and fertilization, work well together, others should be applied separately for the best results. The key is to understand your lawn’s needs and schedule treatments accordingly. Before combining fertilizer with other products, always read the labels and follow the recommended timing for each treatment.
By applying the right treatments at the right time, you will help your lawn grow thicker, stronger, and more resilient throughout the season. Happy growing!
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John Cunningham is an Automotive Technician and writer at Lawnmowerfixed.com.
He’s been a mechanic for over twenty-five years and shares his know-how and hands-on experience in our DIY repair guides.
Johns’s How-to guides help homeowners fix lawnmowers, tractor mowers, chainsaws, leaf blowers, power washers, generators, snow blowers, and more.