When to Fertilize a Lawn

when to fertilize a lawn

A Comprehensive Guide to Timing and Grass Health

Fertilization is one of the most important aspects of lawn care, but without proper timing and sufficient know-how, it’s easy to do more harm than good. When you fertilize at the wrong time, you can end up with an unhealthy lawn and weak roots. This comprehensive guide will help you understand when to fertilize a lawn so it looks great all year round.

Why is fertilization essential for a healthy lawn?

Lawns need nutrients like nitrogen, phosphorous, and potassium for healthy growth. When you apply fertilizer at the right time, your lawn gets the nutrients it needs for optimal root growth and strong green blades of grass.

Without proper nutrients, your lawn suffers and becomes weak, making it more susceptible to drought, weeds, insects, and diseases.

Importance of timing in lawn fertilization

timing fertilizing

Timing is everything regarding lawn fertilization, and choosing the best time to apply fertilizer promotes healthy growth and prevents weeds and diseases. Fertilizing at the wrong time can burn your lawn or foster excess weed growth and diseases. 

Understanding Your Lawn’s Needs

Throughout the year, your lawn’s needs change. Periods of optimal growth are naturally followed by dormancy or drought, and you need to know when to fertilize a lawn to give it what it needs.

Assessing your lawn’s current condition

Take a few moments to assess your lawn’s current condition objectively. Notice as many details as you can, such as problems like bare spots, weak growth, excess weeds, and pet damage.

Is your lawn established or new? Does it appear stressed or healthy? What color is your grass?

You can tell a lot about a lawn by its color. Your grass will naturally change hues throughout the year, depending on how much sun, water, and nutrients it’s getting. But if your grass isn’t bright green, it can be a sign of disease, lack of nutrients, or dormancy.

Fertilization isn’t the only part of lawn care that requires good timing. Be sure to also check out our guide to when you should water your grass.

Identifying your grass type

grass type

When to fertilize a lawn depends on what type of grass you have because different types of grass grow better at certain times of the year.

Warm-season grasses grow best during the spring and summer when temperatures are between 75°F and 90°F (24°C to 32°C). Conversely, cool-season grasses do better in the fall and early spring when temperatures are between 60°F and 75°F (15°C to 24°C). 

Soil testing for nutrient deficiencies

soil testing

You should always test your soil before adding fertilizer or other soil amendments.

Soil testing and analysis provide information about nutrient deficiencies. This will help you choose the right soil amendments and the best time to apply fertilizer on your lawn.

Contact your local extension office to obtain the soil test kits. An in-depth analysis of your soil will help you determine the ground’s organic matter and pH levels. Based on this, you’ll know how often you should fertilize your lawn, and what type of fertilizer you should use.

Seasonal Tips and Recommendations

Lawns are more resilient when they are well-fertilized. And it’s easy to make a year-round lawn fertilizer schedule designed for your type of grass.

Feeding your lawn regularly makes it more resistant to drought, cold, weeds, and other stress factors, and you can enjoy a lush, green lawn that looks good all year.

Spring fertilization

spring fertilizer

Lawns go dormant during the winter. But when they wake up, they need a lot of nutrients for strong root growth. Apply fertilizer in the spring when it starts to grow, which is around the same time it first needs mowing.

If you apply fertilizer too early, your grass puts all that energy into leaf development instead of root growth, making it more susceptible to drought, weeds, and diseases later in the season.

Fertilize warm-season grasses in early spring when they start to turn green after the winter dormancy period, which is usually the end of March or the beginning of April. Temperatures should be around 70°F (21°C), with soil temperatures above 55°F (13°C). 

You should apply spring lawn fertilizer when cool-season grasses are waking up. This is around 55°F (13°C)–usually sometime in March or April, depending on where you live.

Soil temperatures are the best indicator to help you determine when to fertilize cool-season grasses in the spring. Additionally, they are more accurate than calendar dates. 

Summer fertilization

summer fertilizer

If you live in the South, early summer is when to fertilize a lawn because it’s in a period of optimal growth. However, the further north you live, the more careful you need to be with summer fertilization.

If you live in the South, the warm-season grasses in your lawn will benefit from a feeding in early to mid-summer. Until temperatures go over 95°F (35°C), warm-season grasses are still in their peak growing season, and they need adequate nutrients to continue healthy growth. 

Since warm-season grasses don’t go dormant in the summer like cool-season grasses, you don’t need to worry as much about damaging your lawn with summer fertilization. However, it’s best to avoid fertilizing when temperatures go over 85°F (30°C).

On the other hand, cool-season grass growth declines when temperatures go above 75°F (24°C), and you risk burning your lawn if you fertilize it during the summer. Fertilizing during the summer also encourages weed growth, and it’s hard for your lawn to compete against weeds when it’s dormant.

Remember, if your lawn goes dormant when temperatures rise, it’s due to summer heat, not a lack of nutrients.

Fall fertilization

fall fertilizer

As temperatures start to cool in the fall, your grass will start growing again, and it needs a boost of nutrients to maintain healthy growth. When to fertilize a lawn in the fall depends on the type of grass you are growing. 

Warm-season grasses will start to enter a dormancy period when temperatures drop below 75°F (24°C). Therefore, it’s best to fertilize this type of lawn before the end of September. Otherwise, you risk having your lawn damaged by winter kill.

A good rule of thumb is fertilizing warm-season grasses in early fall, about 6 to 8 weeks before the first frost.

At 75°F (24°C), cool-season grasses are coming out of summer dormancy and entering a peak period of growth. As a result, they need a boost of nutrients, and fall is an excellent time to apply a fall lawn fertilizer on your cool-season lawn.

Fertilize in early September as your lawn enters its second growth period. 

Late fall fertilization of cool-season grasses will provide nutrients for early spring growth. Then, depending on where you live, you can fertilize again in October or November, as long as it’s about six weeks before the first frost.

Winter fertilization

dormant grass

There are special winter fertilizers available that help your lawn survive cold winters. These are different from late-fall fertilizers designed to encourage fall growth.

Instead, winter fertilizers contain a ratio of 2:1 nitrogen to potassium, which helps your lawn store food and energy for the winter. When choosing winter fertilization formulas, look for N-P-K ratios of 16-4-8.

Winter fertilizers should be applied by the end of November, usually after the last mow of the season. Avoid giving your lawn heavy doses of nitrogen during the winter because it encourages new growth that cold snaps can damage.

To quote the Beatles, “When you get to the bottom, you go back to the top.” So, listen to Paul. When you finish reading, come back up and click through to our articles about Zoysia, St. Augustine, Fescue, Bahia, Bermuda, Centipede, and Kentucky Blue grasses.

When to Fertilize a Lawn–The Takeaway

When to fertilize a lawn is important if you want it to be green and luxurious. Everything from timing, method, and the type you use will determine the effectiveness of your fertilization program.

Determining the best time to fertilize requires an understanding of what your lawn needs and when it needs it.

The importance of proper timing

Fertilizers give your lawn an immediate nutrient boost that encourages healthy growth.

When applying fertilizers during peak growing seasons, your lawn derives the greatest benefit from fertilizers. So, the type of grass you grow and your growing region play a significant role in the proper timing of lawn fertilization. 

Organic vs. synthetic fertilizers

organic fertilizer

Unlike natural fertilizers that take weeks to break down, synthetic fertilizers give your lawn the nutrient boost it needs within days. Therefore, it’s important to understand the role of different fertilizers in your lawn fertilization schedule.

Natural fertilizers like compost and manure have an advantage over synthetic fertilizers: They provide a broader range of micronutrients. They are slow-acting and provide a steady supply of nutrients over a long period.

However, applying synthetic fertilizers is much easier than applying organic fertilizers, and you get to see results right away.

Related articles

How to Stop Animals from Digging in Your Yard

If your yard looks like a construction zone or battlefield due to the persistent digging of critters, it’s time to learn how to stop them in their tracks. Find out how to stop animals from digging in your yard with these tips and tricks. Why Animals Might Be Digging in Your Yard The first step […]

How to Protect Plants from Frost During the Cold Desert Nights

From scorching hot days to cold desert nights, gardening in the Southwest presents unique challenges. Learning how to protect plants from frost is a critical skill for winter gardening in a desert-like climate.  How Plants Fare During Winter in Deserts Whether growing a vegetable or flower garden, you must take a strategic approach to gardening […]

How to Overwinter Vegetable Gardens in the Pacific Northwest

Before you put your wheelbarrow away, discover how to overwinter your vegetable garden. In the Pacific Northwest, there are many ways to extend your growing season and enjoy a fruitful harvest throughout the winter months. What Is Overwintering? In gardening terms, overwintering is the process that you use to protect plants from harsh winter conditions. […]

10 Expert Tips for Winter Gardening in the Pacific Northwest

Stretching from Northern California to Oregon, Washington, and Idaho, the Pacific Northwest is a diverse and dynamic region. Learn more about exciting opportunities for winter gardening in the Pacific Northwest. What is Winter Gardening in the Pacific Northwest Like? The Pacific Northwest has a temperate maritime climate with mild, wet winters and relatively cool summers. […]