When to Cover Fruit Trees for Frost Protection—and How to Do It, According to Orchardists

As fall settles in and temperatures start to drop, safeguarding fruit trees from frost becomes an essential responsibility for home gardeners and orchardists. Frost can significantly harm budding blossoms and developing fruits, threatening the yield and quality of the upcoming harvest. By implementing proactive measures—such as covering trees or using protective barriers—you can protect your investment and look forward to a fruitful spring.

Here, fruit tree experts offer straightforward tips to help you decide when and how to effectively cover your cherished fruit trees.

When to Cover Fruit Trees

Frost occurs at 32 degrees Fahrenheit or below. "If your fruit tree has open spring blossoms that need protection and the tree is a manageable size to cover, consider covering it at this temperature," says Jacob Mentlik, nursery manager for Fedco Trees and orchardist at After the Fall Farm.

Unlike spring frosts, fall frosts typically do not harm trees unless there is still fruit on them. In that case, if the temperature is expected to reach 32 degrees, it’s advisable to cover the trees. If the temperature drops below 28 degrees Fahrenheit, Mentlik recommends harvesting all your fruit, as this temperature range freezes the fruit, causing irreparable harm.

How to Cover Fruit Trees the Right Way

The best way to shield young or small trees from frost damage is to cover them. To ensure proper protection, follow these straightforward steps.

1. Install stakes: Install stakes around the perimeter of the tree. The stakes support the cloth, forming a cage-like structure and shielding the tree's leaves and blossoms from frost.
2. Add mulch: Water the soil and spread a 3-inch layer of mulch over the soil for root warmth and protection.
3. Cover the tree: Cover the tree with Agribon or a lightweight cloth such as a sheet, burlap, or a reemay garden cloth. Place the cover over the stakes in the mid-afternoon when it's still warm outside. This will help trap warm air inside the cloth. Make sure the entire tree is covered, and that the fabric extends all the way to the ground.
4. Create a seal: Secure the edges of the cloth to the ground using rocks, bricks, or stakes. This will trap the heat from the ground and keep the cloth from blowing away in windy conditions.
5. Remove the cloth: Remove the cloth during the day to allow your tree to absorb the sun’s heat. 
   

How to Protect Full-Sized Fruit Trees From Frost

Fruit tree covers are typically only used for small or young trees. For full-sized trees, orchardists often use the well-known technique of misting or sprinkling water on their trees to create a protective layer of ice on the leaves and buds. As Mentlik explains, "The sprinkler needs to continuously water the trees throughout the cold temperatures for this method to be effective." However, this approach can be risky, as it only works at the precise temperature of 24 degrees Fahrenheit or higher. If the temperature drops below that, the ice could actually damage the trees, Mentlik warns.

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Fruit Trees that Should and Shouldn't be Covered

Knowing which fruit trees require protection and which can tolerate frost is essential for success. In general, established, cold-hardy trees like apples, pears, peaches, and plums are not affected by fall or winter frost and do not need to be covered, according to David Fried, owner of Elmore Roots Fruit Tree Nursery. In fact, these trees require cold periods to set fruit.

However, Fried notes that all fruit trees are susceptible to frost when they are in bloom, and should be covered if temperatures drop below 32 degrees Fahrenheit during spring.

Trees that are vulnerable to frost no matter the time of year include citrus, avocado, apricot trees, and subtropical and tropical trees, especially those that are young or newly planted. These trees require protection during frosts to ensure their health and longevity.

Risks of Not Protecting Fruit Trees From Frost

While the ultimate impact of frost on a tree depends on its age, variety, and the severity of the frost, failing to protect your trees from frost can cause considerable damage. This is especially true if they are young, late-season fruiters, or not well-suited to your growing zone. An early or severe fall freeze can be especially harmful to mature trees that have not yet fully entered winter dormancy. The result can be damaged leaves, buds, and new growth. This may significantly affect fruit production in the following season. Peach trees are particularly affected by frost. Frost can kill the tree’s cold-sensitive buds, blossoms, and developing fruit before it has fully adjusted to winter conditions.

However, while frost may harm blossoms and fruit, the trees themselves remain unaffected, according to Mentlik. "A frost signals fruit trees to begin the process of dormancy and acclimatization to winter temperatures," he explains. This is another important reason to choose trees that are suitable for your growing zone.