When to Fertilize Your Lawn

If you fertilize your lawn at the wrong time of year, you might as well not fertilize it at all. So, what is the right time of year? That depends on your grass type’s growing season. This guide details when to fertilize your lawn, whether you have cool-season or warm-season grass.

Each grass type has its own fertilization needs. If you already know what type of grass you have, visit our comprehensive fertilizer guides below to ensure your lawn receives individualized care:

• When to Fertilize Fescue
• When to Fertilize Kentucky Bluegrass
• When to Fertilize Centipedegrass
• When to Fertilize Buffalograss
• When to Fertilize Zoysiagrass
• When to Fertilize Bermudagrass

When to Fertilize Your Lawn

The first step in knowing when to fertilize is to identify the type of grass growing in your yard.

There are two primary varieties of grass: cool-season and warm-season. Cool-season grasses grow in the country’s northern parts, while warm-season grasses grow in the southern region. A third of the country is in the Transition Zone, where either grass can grow. To see what zone you’re in, look at this USDA hardiness zone map.

When planning a fertilization schedule that works for you, it’s also important to consider soil quality and the local climate. Soil testing determines the nutrient levels in your soil, giving you a starting point for your fertilization plan. Different climates typically impact fertilizer requirements depending on temperature and moisture levels. Regular monitoring and adjusting based on your grass’ needs will contribute to a healthy, thriving lawn you won’t want to leave.

When to Fertilize Cool-Season Grasses

Cool-season grasses experience their most vigorous growth during the cooler parts of the year, particularly in the spring and fall. During this time, they’re better able to utilize available moisture and nutrients, resulting in lush, silky lawns. These grasses flourish in climates with warm summers and cold winters.

Well-known cool-season types include:

• Kentucky bluegrass
• Bentgrass
• Ryegrass
• Fine fescue
• Tall fescue

Avoid feeding your cool-season grass too early, as this will encourage leaf growth but leave the root system weaker and susceptible to damage. Be mindful of soil temperatures, which for cool-season grasses need to be around 55 degrees Fahrenheit for successful fertilization.

Follow up with a winterizing variety six to eight weeks after your late fall fertilizer application. This is best done when your cool-season grass is still green, but has stopped growing (air temperatures will usually be in the 50 to 55 degree Fahrenheit range). Winterizing fertilizer is full of potassium and phosphorus to help your grass maintain strong roots in winter but low in nitrogen to prevent leaf growth during this time. 

Consider this fertilization schedule for cool-season grasses:

• 1st round – Early spring (mid-April)
• 2nd round – Early fall (September) 
• 3rd round – Late fall (mid to late October)

When to Fertilize Warm-Season Grasses

Warm-season grasses grow best in places with warm year-round temperatures. They’ll often turn brown in the winter, which means they’ve gone dormant. Depending on where you live, winter dormancy usually lasts about three to five months.

Types of warm-season grasses include:

• Bahiagrass
• Zoysiagrass
• Bermudagrass
• Buffalograss
• Centipedegrass
• St. Augustinegrass
• Carpetgrass

Feed your warm-season grass every six to eight weeks during its active growth season (see above). Start your first round when soil temperatures have been holding steady at 65 degrees Fahrenheit for a few weeks. 

When it’s time for your summer feeding (the most important feeding time for warm-season grasses), adding some organic fertilizer to your regular fertilizer is a good idea. Whether you add manure, bone meal, or compost, this boost of nutrients can better prepare your warm-season grass for winter dormancy.

Consider this fertilization schedule for warm-season grasses:

• 1st round – Mid to late spring (around April)
• 2nd round – Early summer (June)
• 3rd round – Early fall (September)

FAQ About When to Fertilize Your Lawn

How long should I keep pets off my lawn after fertilization?

Keep your lawn pet-free for about 24-48 hours. It’ll give the fertilizer plenty of time to sink into the soil and keep your pets safe from any potential effects of the fertilizer. If ingested, commercial fertilizer may lead to allergic reactions, while organic fertilizer has been known to cause indigestion and bowel obstruction.

What happens if I over-fertilize my lawn?

Too much of a good thing is a bad thing. Too much fertilizer can weaken your lawn and leave it vulnerable to pests and diseases – the exact things you want to prevent. Not to mention that excess liquid fertilizer can contaminate nearby waterways and put people at risk.

How should I store my fertilizer?

When it comes to fertilizer storage, a good rule of thumb is following the directions provided by the manufacturer. These usually include:

• Storing the fertilizer in a dry, cool, secure location – preferably in its original container.
• Keeping it away from pets, children, or any other critters that may gain access to the storage space.
• Making sure the fertilizer is kept away from flammable products.

Get Top-Notch Help From a Pro

By now, you know that timing is a critical factor in achieving a thriving outdoor space. Aligning your fertilization schedule with your grass’ natural cycles and other lawn care practices will result in proper growth and sustained vigor against hot summer temperatures and winter challenges.

Whether you’re a DIY-er or prefer hiring a local lawn care pro to give your lawn the nutrients it deserves, fertilization is a must if you dream of a thriving outdoor space for years to come. 

Main Photo Credit: Shutterstock

Andie Ioo

In my free time, I enjoy traveling with my husband, sports, trying out new recipes, reading, and watching reruns of '90s TV shows. As a way to relax and decompress, I enjoy landscaping around my little yard and DIY home projects.

Posts by Andie Ioo