After a long winter, your lawn emerges hungry and ready for nutrients to fuel healthy growth. Fertilizing in the spring gives your grass the essential nutrients it needs to develop strong roots, vibrant colour, and resilience against summer stress.
When you feed your grass the right nutrients at the right time, you're investing in a lawn that can better resist weeds, drought, and disease throughout the growing season. This guide covers the keys to successful spring fertilizer use, including timing, how to choose the right fertilizer, and proper application.
When to Fertilize Your Lawn in Spring for Best Results
Timing your spring fertilizer application correctly can make all the difference between a thriving lawn and wasted effort. Factors to consider include:
- Temperature: Grass typically starts growing when soil temperatures consistently reach 10°C to 18°C (50°F to 65°F). That makes late April to early May the best time to start fertilizing in most regions.
- Active growth: Fertilize when your grass is actively growing, not just showing green colour. Wait until you've mowed your lawn for the first time before applying spring fertilizer.
- Natural indicators: When forsythia shrubs bloom with bright yellow flowers, it's a reliable sign that soil conditions are right for fertilization.
Take your time with the process, even if you're eager to see results. Fertilizing frozen or waterlogged soil provides no benefit to your grass. The nutrients can wash away with spring runoff, wasting your investment and potentially harming nearby waterways. Patience in timing your first application pays off with better nutrient absorption and stronger grass growth.
Regional differences affect when to start fertilizing. Northern areas with longer winters should wait until later in May or early June. In warmer parts of the country, some lawns may be ready for fertilization by early April. However, applying fertilizer in late March is rarely appropriate in Canadian climates. Wherever you’re located, measured soil temperatures are the best indication that it’s time to fertilize.
A local landscaping professional can help you determine the optimal timing based on your location, soil temperature, and grass growth patterns.
Choosing the Best Lawn Fertilizer for Spring
The best lawn fertilizers for spring utilize nitrogen-rich formulations to help your grass recover from winter and establish strong growth. Look for fertilizers with 20–32% nitrogen content, such as 32-0-6 or 20-5-10 formulations. These high-nitrogen products provide the fuel your grass needs to green up quickly and develop thick, healthy growth.
Below, we’ll cover additional variables that can help you choose the best fertilizer for your lawn.
Understanding NPK ratios
NPK ratios represent the percentage of nitrogen, phosphorus, and potassium in your fertilizer. You’ll see NPK ratios represented as three numbers on fertilizer bags; they’ll tell you exactly what nutrients you're applying to your lawn.
- Nitrogen: The first number represents nitrogen, the most important nutrient for spring growth. It promotes lush green colour and stimulates new shoot development.
- Phosphorus: The middle number is often zero, since many soils already contain adequate phosphorus levels.
- Potassium: The third number represents potassium, which supports overall plant health and helps grass develop strong root systems that withstand summer heat and drought stress.
Slow-release vs. quick-release options
Slow-release fertilizers offer the greatest benefits for spring lawn care. These products release nutrients gradually over 8–12 weeks, providing consistent feeding that reduces the risk of fertilizer burn.
Quick-release fertilizers provide immediate results but require more careful application and immediate watering, which can be detrimental if the soil is frozen or waterlogged from snowmelt.
Granular vs. liquid fertilizers
Granular fertilizers work well for most homeowners because they're easy to apply with a spreader and provide even coverage. Water your lawn thoroughly after applying granular fertilizer to activate the nutrients.
Liquid fertilizers absorb quickly through grass blades, allowing for rapid greening, but require more frequent applications. Apply liquid products during cooler parts of the day to prevent leaf burn.
Spring Fertilizer Application Schedule and Best Practices
Ready to start your spring lawn care routine? Here’s a step-by-step guide to help ensure a healthy and robust lawn for the summer:
- Start with soil testing. Soil testing determines your lawn's specific nutrient needs. Most grasses prefer a soil pH between 6.0 and 7.0 for optimal nutrient absorption. If your soil falls outside this pH range, consider using lime to raise the pH or sulphur to lower it before fertilizing.
- Wait for the right soil temperature. Apply your first spring feeding when soil temperatures reach the optimal range (10°C–18°C) and grass begins active growth. Follow up with a second application 6–8 weeks later, typically in early to mid-June. This schedule provides consistent nutrition during your lawn's peak growing season.
Follow these best practices for optimal results from your spring fertilizer application:
- Provide routine maintenance. Regular lawn and bed maintenance ensures your grass stays at the optimal height for fertilizer absorption. Set your mower to cut grass at 6–8 cm (2.5–3 inches) high. Taller grass promotes deeper root growth, helping your lawn withstand stress throughout the growing season.
- Ensure appropriate conditions. Apply fertilizer when the grass is dry but the soil has adequate moisture. Avoid fertilizing during drought conditions or immediately before heavy rainfall. Light morning dew is acceptable, but wet grass blades can cause granular fertilizer to stick and potentially burn the grass.
- Calibrate your spreader. Using too little fertilizer won't provide adequate nutrition, while using too much can burn your grass and waste money. Most spreaders include setting charts, but test your application rate on a small area first to verify accuracy.
Common Spring Fertilizing Mistakes to Avoid
For optimal results and a thriving lawn, avoid these common fertilizing pitfalls:
- Avoid frozen or waterlogged soil: Wait for complete thawing and drainage to ensure nutrient absorption and prevent runoff.
- Don't over-apply: Follow label directions. More fertilizer doesn't mean better results—in fact, over-fertilizing can harm your lawn!
- Irrigate if dry: Ensure sufficient water for nutrient absorption and to prevent grass burn, especially during drought conditions.
- Check the forecast: Skip fertilization if heavy rain is expected within 24 hours to avoid nutrient wash-away. Aim for 24–48 hours of moderate conditions.
- Prevent runoff: Apply fertilizer only to your lawn. Sweep any stray granules back onto the grass to protect waterways.
- Don't forget about weeds: Spring fertilization works best when combined with weed control to prevent weeds from competing with your grass for nutrients.
Get Professional Spring Lawn Fertilization Services
Professional lawn care ensures optimal results with less effort on your part. The Grounds Guys offer comprehensive lawn care programs tailored to your lawn's specific needs, taking the guesswork out of timing, application rates, and product selection. Contact your local team for a customized assessment and let the experts handle your spring lawn care.
FAQs About Spring Lawn Fertilizer
As an industry leader, The Grounds Guys are committed to using our 20+ years of landscape knowledge and experience to help bring your vision for your property to life. This includes answering your questions about landscape and lawn care services. Below are answers to some of the most frequently asked questions about spring lawn fertilizer
What happens if I fertilize my lawn too early in spring?
Fertilizing too early can waste nutrients and harm your lawn. When soil temperatures are below 10°C (50°F), grass roots aren't actively growing and can't absorb nutrients effectively.
Early fertilization can also stimulate top growth at the expense of root development, making your lawn more vulnerable to summer stress. Wait until soil temperatures consistently reach 10°C to 18°C and your grass shows active growth before applying spring fertilizer.
How long should I wait to mow after fertilizing my lawn?
After applying granular fertilizer, wait at least 24–48 hours and water your lawn to help the nutrients absorb before mowing.
For liquid fertilizers, allow 2–4 hours for the product to fully dry before mowing. Mowing too soon can interfere with nutrient absorption and may reduce the effectiveness of your application.
Can I fertilize my lawn if rain is expected?
Avoid fertilizing if heavy rain (more than 1.25 cm or 1/2 inch) is expected within 24 hours. Heavy rainfall can wash away nutrients before grass roots absorb them, wasting your investment and potentially causing runoff into waterways. Light rain or watering after fertilization can be beneficial, but wait for moderate weather conditions that will last 24–48 hours after application for best results.
This article is intended for general informational purposes only and may not be applicable to every situation. You are responsible for determining the proper course of action for your home and property. The Grounds Guys are not responsible for any damages that occur as a result of this blog content or your actions. For the most accurate guidance, contact The Grounds Guys location nearest you for a comprehensive, on-site assessment.