What’s the Difference Between Fall Fertilizer and Winter Fertilizer

Garden Grass Care Fertilizer

The main differences between a fall fertilizer and a winter fertilizer are the time of application, the type of nitrogen, and the benefits provided for the lawn. 

Both types of fertilizer cover a similar NPK range and are hard to differentiate in garden shops unless the label specifies what the fertilizer is for. In this article, we cover the details that make the difference.

Type of nitrogen

  • Fall fertilizer: 50% slow-release nitrogen
  • Winter fertilizer: quick-release nitrogen

“A fall fertilizer is a 50/50 mix of slow- and fast-release sources and applied soon after the heat of the summer is over. The chief benefit is to help the turf recover from summer stress,” says John Fech, extension educator for the University of Nebraska-Lincoln.

The turf has plenty of time to absorb and use the nutrients, and the feeding is done gradually, protecting the grass from forced foliage growth. 

On the other hand, winter fertilizer is spread late in the growing season and has only a small window to feed the turfgrass. Fech suggests homeowners apply a light dose of fast-release nitrogen, such as urea, ammonium nitrate, or ammonium sulfate.

“If applied at a very low rate, these sources are quick release and can be immediately absorbed by the lawn without the likelihood of surface runoff or leaching.”

Eco-friendly tip: To prevent nitrogen pollution, if you apply more than 0.5 lbs. per square foot, use a fertilizer with slow-release nitrogen.

Time of application 

Lawn fertilizer being spread with a manual fertilizer spreader
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  • Fall fertilizer: First application of the fall (September). 
  • Winter fertilizer: Last application of the year (October to December).

You can apply a fall fertilizer at the beginning of the fall as soon as the temperatures go below 90 degrees Fahrenheit. It’s when the cool-season grasses exit summer dormancy and prepare for the second growing season of the year. 

The winter fertilizer is for the last application of the year that you make in late fall. You apply it when the grass is close to dormancy, near or after the last mow. It’s typically when temperatures drop below 50 degrees Fahrenheit.

You can use both treatments on cool-season grasses. If so, apply the winter fertilizer 4 to 6 weeks after the fall fertilizer. Our guide, “When to Apply Winter Fertilizer,” explains more about timing a winter fertilizer.

Application rate 

Fall fertilizer: 1.0 lbs. N/1,000 square feet

Winter fertilizer: 0.50 to 0.75 lbs. N/1,000 square feet

The general recommendation is to apply the regular rate when fertilizing in early fall and only a fraction when applying the winter fertilizer later in the season. Purdue University experts recommend 1 lb. nitrogen per 1,000 square feet for the September application and 0.5 to 0.75 lb. nitrogen per 1,000 square feet for the November application.

Fertilization purpose and turfgrass benefits

Man fertilizing green grass on sunny day, closeup
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  • Fall fertilizer (effects in the fall): recovery after summer stress, improved plant health, overall plant growth 
  • Winter fertilizer (effects from late fall to spring): better fall and winter color, nutrient reserves, improved resistance to winter kill, faster and healthier spring green-up

Late summer to early fall lawns are tired and damaged from summer heat and drought. You apply a fall fertilizer to support grass growth. The nutrients a fall fertilizer provides help the turf recover, regain its beautiful green color, and grow new leaves, shoots, and roots. 

Since most energy is used for growth, the reserves that grass stores in the crown and roots in early fall are low and slow to replenish. This is where the winter fertilizer comes in.

Winter fertilizers, as the name suggests, help prepare the lawn for winter. Since leaf and shoot growth is slow to none by the time of the application, the nutrients they provide are used for more long-term benefits, such as:

  • Hardening off the plant structure to improve resilience and reduce winter kill.
  • Making energy reserves for the winter and the spring green up.

Read more about what winter fertilization offers in our guide, “Benefits of Winter Fertilizer.”

Importance in the lawn care calendar

nitrogen, phoshporous and potassium fertilizers on the ground
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  • Fall fertilizer: essential for cool-season grasses, rarely needed for warm-season grasses
  • Winter fertilizer: useful when the turf is weak, thin, or chlorotic at the end of the season. 

Spreading fall fertilizer in early fall is the most important application for the year for cool-season grasses. It’s when the grass is actively growing and absorbs all the nutrients best.

Winter fertilizer is an optional treatment to help a lawn in poor health, improve deficient soil, or avoid early spring fertilization.

Environmental risks

  • Fall fertilizer: better nutrient absorption, low to no leaching or runoff.
  • Winter fertilizer: higher risk of nitrogen pollution.

Applying a winter fertilizer late in the season depends on perfect timing. If you wait too long and the grass starts to brown, you apply the fertilizer to dormant grass that no longer feeds. Because of the increased risks of nutrient pollution, some experts say using a winter fertilizer should be avoided. 

Carl Schimenti, urban environmental scientist at the School of Integrative Plant Science, says no fertilizer should be applied once the turfgrass stops actively growing.

“Dormant fertilizer applications are not taken up by the plant, and instead, the nutrients are lost into the environment where they can cause water quality concerns. It is common for people to apply dormant fertilizer to help with spring green-up. The same green up is achieved with fall fertilization, without the risk of leaching and runoff.” 

Enjoy the benefits of professional lawn care!

Not so fond of choosing and spreading fertilizers? The pros are here to help. Find a local lawn care company with Lawn Love and have your lawn taken care of from A to Z. Lawn fertilization, yard cleanup, mowing, and aeration – all you need to keep the lawn lush and thick.

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Sinziana Spiridon

Sinziana Spiridon is an outdoorsy blog writer with a green thumb and a passion for organic gardening. When not writing about weeds, pests, soil, and growing plants, she's tending to her veggie garden and the lovely turf strip in her front yard.