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When to Apply Winterizer Fertilizer

You might not have used it before, but you’ve most likely heard about a winterizer fertilizer from fellow lawn owners. Some people think that such a fertilizer is merely sensationalized by manufacturers to reap profits while others swear by its effectiveness.

So, what exactly is a winterizer? If you are curious to know the contents and when to apply winterizer fertilizer, go ahead and read our guide.


What is a Winterizer Fertilizer?

Every fertilizer package will always contain a number ratio indicative of the percentage of its most active ingredients: nitrogen, phosphorus, and potassium. 

Scotts Turf Builder WinterGuard Fall Weed and Feed

Source : Amazon

The average lawn fertilizer will have a number ratio of 29-3-4. On the other hand, a winterizer fertilizer will have more potassium and less nitrogen compared to regular fertilizers.

A specific example would be the WinterGuard winterizer fertilizer with a 24-2-14 ingredient ratio, which is noticeably different when compared to the 29-2-4 Turf Builder fertilizer from the same company.

Why does a winterizer have an increased amount of potassium? Well, this ingredient is known to accelerate the root system growth of grasses. More importantly, potassium helps grasses tolerate colder temperatures.

Of course, the dominant ingredient even in a winterizer fertilizer is nitrogen because all lawns need this nutrient the most regardless of the season. Likewise, there is still a bit of phosphorus since this is essential for fruit production and root development.

When to Apply Winterizer Fertilizer

applying winterizer fertilizer

Source: Amazon

A winterizer fertilizer should be applied to your lawn during the fall season when grass plants begin to store nutrients for the winter. During this season, grass blade growth begins to slow down due to the fact that transpiration has been reduced despite the continued processes of photosynthesis.

With a winterizer fertilizer, your grass plants will be able to preserve sufficient energy and nutrients throughout fall. In particular, the application should ideally be conducted during the late phase of the season.

This is from the middle of November up to the beginning of December, especially in the northern regions in the United States. During this period, the grass will stop growing but will still appear fresh and green.

Furthermore, the grass plants are still active beneath the soil. Interestingly, it can be argued that the most crucial fertilizer application of the year is the winterizer application. 

This is due to the fact that the winterizer positively affects the plants not just during winter but also in spring. The winterizer fertilizer ensures that your grass plants have enough stored energy and nutrients to stay green even when the ground completely freezes in the winter season.

Once the temperature becomes warming in spring, the remaining nutrients are utilized for optimum growth.

Here is a video further discussing winterizer fertilizer:

When Not to Use a Winter Lawn Fertilizer

A winterizer fertilizer should not be applied on the lawn during the fall season with the hopes of accelerating grass blade growth. Its main purpose, after all, is to help the grass plants survive the coming winter season and to make it thrive in the spring. 

If you are hoping to promote grass growth in fall, you should fertilize your lawn during the earliest parts of the season. Similarly, you should skip using a winter fertilizer even during the late stage of the fall season if your grass plants are already suffering from heavy discoloration, which is caused by cold weather. 

This means that it’s already too late to apply the winterizer. On a related note, you also cannot use this type of fertilizer during the fall season if your lawn has sandy soil. This type of soil can lead to nitrogen leaching that can result in ground water contamination. 

You must never use winterizers for warm-season grass varieties such as centipede, Zoysia, St. Augustine, and Bermuda grass. All of these grass species thrive in warm regions and are dormant during the winter season, so using such a fertilizer on them would be a waste. 

Instead of a winter fertilizer, these warm-season grasses should receive a fertilizer containing a good dose of potassium during the spring and summer seasons.

Refer to our guides for the best fertilizers for spring along with our review of the best fertilizer spreaders for 2022

It is Essential to Know When to Apply Winterizer Fertilizer

In conclusion, the winterizer fertilizer should be applied during fall. In particular, it’s best to do it when the grass growth has been put to a halt and when the grass plants begin to store all the energy and nutrients it can to prepare for the winter season.

If you have any questions, give us a comment. We hope that this guide helped you learn when to apply winterizer fertilizer to your garden. 

About the Author Ann Katelyn

I'm Ann Katelyn, Creator and Chief Author of Sumo Gardener. Since I was a child I've always been fascinated with plants and gardens, and as an adult this has developed into my most loved hobby. I have dedicated most of my life to gardening and started Sumo Gardener as a way to express my knowledge about gardening with the hope of helping other people's gardens thrive.

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