Does Fertilizer Keep Plants From Freezing?

When the cold months hit, it’s important to be prepared with systems in place to prevent your plants from suffering damage due to freezing. What is the best way to keep your plants safe in the winter? Can fertilizer keep your precious plants from an ugly freeze?

Fertilizer does not keep plants from freezing. Fertilizer is usually applied during early spring after the frost has broken. However, there are numerous ways to effectively prevent freezing in your garden by preserving warmth and creating a barrier between your plants and the bitter cold. 

The rest of this article will explain some effective strategies to prevent freezing in your garden. I will also share some insight into the purpose of fertilizer and how you can use it to help revitalize your plants after the cold months. 

Key Takeaways

  • Fertilizer Limitations: Fertilizer is essential for plant growth but does not prevent freezing. It’s most effective when applied in early spring, post-frost.
  • Effective Cold Protection Strategies: Include covering plants with mulch or blankets, bringing potted plants indoors, and watering during warmer afternoon hours.
  • Winter Fertilizer Use: Special winter fertilizers, or ‘winterizers’, are useful for lawns in fall but should not be applied to garden plants.
  • Post-Winter Revitalization: After winter, applying fertilizer can help rejuvenate plants and encourage healthy growth as temperatures rise.

Effective Strategies to Prevent Plant Freezing

Preventing your plants from freezing depends on the type of plant you have and what kind of special care it requires. 

Some of the best ways to prevent freezing during the winter months include:

  • Covering plants with mulch or a blanket to keep them warm
  • Bringing potted plants indoors or into a warmer area
  • Watering plants during the afternoon, when the weather is warmest
  • Applying a winter fertilizer, also known as winterizer, to your lawn (not your garden) during the fall, before the first freeze

Most plants prefer a temperature of around 55 °F (13 °C) throughout the year to stay healthy. Freezing temperatures of 28 °F (-2 °C) are the most dangerous to plants, often causing the plant to die completely if not adequately protected for the winter season. A lighter frost is less damaging but could still be dangerous for smaller, more delicate plants.

One of the most effective ways to prevent your plants from freezing is to prepare before the first freeze. In order to prepare, you’ll want to take any potted plants that you have outside and bring them into the house, garage, or greenhouse. 

If you don’t have space inside to bring your potted plants, you can instead wrap the pots with burlap, blankets, or even bubble wrap to contain heat and protect the roots.

Plants that are rooted in your garden or backyard are more complicated to protect, but it can be done. In order to keep these plants warm through the freezing weather, you will need to cover them to preserve the warmth. 

To cover your plants and keep them warm during a freeze, you can use:


A thick layer of mulch over the top of your plant will provide insulation and protection for the roots growing underneath the soil. This method is typically used when the foliage is not being preserved, but the roots underneath will provide new growth in the spring.


Blankets and other linens make great plant coverings because they are more breathable than plastic and contain heat while still allowing airflow. Blanket plant covers are available for purchase in various shapes and sizes.

Be sure to get yours in a large sheet. You can cut the sheets to fit or purchase multiple to cover even larger areas.

Cardboard Boxes

Larger plants that cannot be easily covered with mulch or blankets typically do well underneath cardboard boxes. Depending on the temperature, these boxes might only be necessary as a nighttime cover and can be removed again during the day to allow for exposure to sunlight. 


Burlap is a fantastic plant cover for frost protection. During a deep freeze, burlap does not provide enough insulation to protect the plants effectively, but this lightweight material will do the trick for a lighter frost!


Plastic coverings are not ideal on their own, as they tend to trap moisture and can cause damage to the plants; however, they are excellent when paired with another covering.

If you lay a blanket down first and then layer the plastic on top of that, your plants will have superior protection from any deep freeze. 

The Original Purpose of Fertilizer

Regular, all-purpose fertilizer is commonly used in the spring months to revitalize and boost growth in your plants as the growing season begins. 

Fertilizer is composed of three main components:

  • Nitrogen (N)
  • Phosphorus (P)
  • Potassium (K)

These components are identified on each bag of fertilizer as N-P-K, with numbers indicating the percentage of that nutrient provided by the fertilizer. Some options are fully balanced, while others have different levels of each nutrient.

There are many different types of fertilizers for specific plants and specific goals, with various levels of each NPK component.

Fertilizers are most effective when applied during early spring but after the last frost or freeze. Fertilizing during the freezing season can be detrimental to the growth of your plants. While it is highly beneficial in promoting healthy growth, it does not provide any protection whatsoever from a harsh freeze.

The nitrogen, phosphorus, and potassium in most fertilizers provide your plants with essential nutrients and encourage prosperous, healthy growth. In vegetable and fruit gardens, fertilizer promotes increased productivity, giving you a higher volume of produce! 

Winter Fertilizer: Preparation, Not Protection

There are some special-purpose types of fertilizer, including winter fertilizer. Winter fertilizer, or winterizer, is used to promote food storage and healthy roots during the cold months. This type of fertilizer should be applied in the fall, about 6-8 weeks before the anticipated first freeze.

Winterizer strengthens your soil and helps provide the nutrients necessary to prepare for the winter months. While it doesn’t prevent your plants or lawn from freezing, it does help to improve the health of your greenery, increasing the likelihood that it will survive the frost.

Winter fertilizer is an excellent tool for your front or back lawn, but it should not be used in your garden. Fertilizing garden plants during the fall or winter will promote new growth, which will be immediately killed off when the first freeze hits. Protecting your garden plants with coverings and retaining warmth should be the focus when winterizing your garden. 

Revitalizing Plants After Winter

When the last freeze has defrosted, and it’s time to uncover your plants in anticipation of spring, consider fertilization. 

Using a fertilizer soon after the last freeze and into the start of spring can be an excellent way to revitalize and bring new life back to your plants. After being covered for months, your plants are ready for some sunshine and nutritional support! 

Once the freezing temperatures and threat of frost has passed, remove the blankets or other coverings from your plants and bring your potted plants back outside. You’ll want to gently water your plants and apply a light layer of fertilizer.

As the temperatures warm up, you can continue to apply fertilizer on a schedule appropriate for your property to improve the quality of the soil and encourage healthy leaf and bud growth in your plants. 

Fertilizer can be an effective tool throughout the entire growing season, so don’t be afraid to reapply on a regular schedule. In fact, most plants show the most positive growth from fertilizer when it is continuously applied throughout the peak growing season. 


While fertilizer does not prevent your plants from freezing, it can help boost your plants’ health during the spring and summer months so that when the cold months start, your roots are healthy and well-supported. 

In order to prevent your plants from freezing, it is necessary to set up a system to protect your plants from the cold. This system should involve covering your plants and retaining heat around them in order to protect both the foliage and, especially, the roots. 

Ensuring your plants have sufficient water and warmth during winter will assist in preventing cold damage.

Dr. Moritz Picot

Dr. Moritz Picot is a horticulture enthusiast and the founder of, where he serves as the lead content writer. He established the website in 2022 as a valuable resource for both gardening aficionados and beginners, compiling all the gardening tips he has accumulated over the past 25 years. Alex has a passion for nurturing plants, transforming backyards into inviting spaces, and sharing his knowledge with the world.

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