How to Freeze Kale: Blanching, Packing and Using Frozen Leaves

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Knowing how to freeze kale lets you keep a harvest or a store-bought bunch for months instead of days. Kale is one of the hardier leafy greens, and extension publications list it among the greens that freeze well. The method has a few steps that affect the result: choose young, tender leaves, trim the stems, blanch the leaves briefly in boiling water, cool them quickly, drain them, and pack them airtight. This guide walks through each step using three university extension sources and explains what those sources do and do not cover.

Quick answer

Pick young, tender leaves, wash them well, and trim away the tough stems.
Water blanch kale for about 2 minutes, according to Penn State Extension’s timing for greens other than collards.
Cool the leaves promptly, drain them well, then pack them in airtight containers or bags with the air removed.
Partially thaw frozen greens before cooking so they separate and cook evenly.

How we chose

This guide relies on three university extension publications, each opened on 2026-10-27. The Penn State Extension page covers freezing and other preservation methods for hardy greens, including kale. The University of California Master Gardener and Cooperative Extension publication on preserving spring greens covers kale directly. The New Mexico State University Extension publication E320 covers freezing vegetables, including the preparation steps for greens. Retail product pages and recipe blogs were not used as the basis for any fact in this article. Where a source gives a specific time, this guide reports it and names the source. Where a source gives only a method, this guide describes the method without adding a number.

Choosing and preparing kale for the freezer

Start with the leaves. The New Mexico State University Extension publication instructs readers to “Select young, tender greens.” Older, tougher leaves do not blanch as evenly and can taste bitter after freezing. Penn State Extension notes that when drying greens, growers should use young, tender leaves, and the same principle applies to freezing.

Wash the leaves thoroughly to remove soil and grit. The NMSU publication lists washing as the first preparation step, followed by trimming. Trim the stems from the leaves. The same publication includes “Trim leaves” as a preparation step.

Work in small batches so that the leaves do not crowd the pot.

Blanching kale before freezing

Blanching means briefly heating vegetables in boiling water or steam before freezing. Penn State Extension states that “The preferred method of preserving hearty greens is freezing because it provides a higher quality product than canning or drying.” In the same publication, the blanching guidance says to “Water blanch collard greens for 3 minutes and all other greens for 2 minutes.” Kale is one of the greens named in the “all other greens” group, so 2 minutes of water blanching is the timing this source gives for kale.

Use a large pot with plenty of water. Bring the water to a full boil, add the prepared leaves, and start timing once the water returns to a boil. Remove the leaves after the set time. Keep to one method for each batch so that the timing matches the method.

After blanching, cool the leaves in cold water until they are no longer warm, then drain them well before packing. This guide reports only the water blanching time that the sources give; the sources do not provide a separate cooling time for kale.

Packing and freezing kale

Pack the cooled, drained kale into freezer bags or rigid containers. Portion the kale in the amounts you typically use in a recipe, so you can take out only what you need. The Penn State Extension page advises sealing and freezing in amounts typically used in a favorite recipe. Remove as much air as you can from bags, then seal them. Label each package with the date and the contents, and place the packages in a freezer that holds a steady temperature.

Another approach is to form small mounds of blanched kale, freeze them on a tray, and then move the frozen portions into a bag. The Penn State Extension page describes a related method: more mature leaves might be chopped, blanched, drained, and blotted dry to be tray frozen. Tray freezing keeps the portions separate, so you can remove a single serving without thawing the whole batch.

Using frozen kale

Frozen kale can go straight into soups, stews, sauces and casseroles. Greens frozen as a solid block benefit from partial thawing before cooking. The NMSU publication says that “Greens should be partially thawed and separated before cooking.” Separating the leaves first makes it easier to add a measured amount and keeps the pieces from clumping in the pan. Penn State Extension notes that while most frozen vegetables can be cooked directly from the freezer, greens frozen as a solid block should be partially thawed before heating to prevent overcooking the vegetables. This is the reason to thaw block-frozen kale before adding it to a hot pan.

The sources in this guide describe frozen kale for cooked use. None of them describes frozen kale for raw salads, so this guide does not recommend that use.

Canning and drying as alternatives

The UC publication on preserving spring greens says to “Preserve extra spinach, collards, kale and other spring greens by freezing, pressure canning, or drying them.” Penn State Extension states that freezing is the preferred method for hearty greens because it gives a higher quality product than canning or drying. Canning greens involves specific times and pressures, and the sources in this guide give timing only for freezing. For canning, follow tested USDA or extension guidance rather than a general recipe. For drying, the UC publication notes that only young, tender leaves should be used for kale chips.

Common mistakes to avoid

Freezing unwashed kale. Grit stays in the leaves and is hard to remove after freezing.
Using old, tough leaves. Penn State Extension and NMSU both point to young, tender greens.
Skipping the cool-down step. Leaves left in warm water keep cooking after blanching.
Packing wet leaves. Drain the leaves well before they go into the package.
Blanching too many leaves in one batch. Work in small batches so that each leaf is handled evenly.

For more on preserving garden produce, read how to preserve tomatoes, which covers a different crop but the same basic concerns about preparation and packaging. If you are still growing your own greens, how to grow collards from seed covers a closely related green that Penn State Extension groups with kale in its freezing guidance.

What we could not verify

The three sources used here do not give a single total storage time for frozen kale in months, so this guide does not state one. They also do not provide a kale-specific steaming time from a verified page, so steaming times are not included. The University of Minnesota Extension guidance on freezing leafy greens could not be opened during this check, so its specific steps are not part of this guide.

What the sources do not say

None of the verified pages give a kale-specific freezer life. The sources also do not describe a verified procedure for freezing kale in a sauce or in prepared dishes. The Penn State Extension page names kale among hearty greens that can be frozen, but its blanching time is grouped under “all other greens,” not listed separately for kale. Readers who need a kale-specific chart should check a current extension publication before following a time table.

Frequently asked questions

Do I need to blanch kale before freezing it?

The sources in this guide describe blanching as the step before freezing. Penn State Extension gives water blanching times for greens, and the NMSU publication describes the preparation steps that come before freezing. Freezing unblanched kale is not described as a verified method in these sources.

How long should kale be blanched?

Penn State Extension says to “Water blanch collard greens for 3 minutes and all other greens for 2 minutes.” Kale falls in the second group, so 2 minutes is the time this source gives for water blanching kale. Use a timer and start counting once the water returns to a boil.

Can I freeze kale stems?

The sources reviewed here say to trim the leaves and remove the thick center ribs, and they describe chopping more mature leaves for tray freezing. They do not give a separate verified method for freezing kale stems, so this guide does not describe one.

Should frozen kale be thawed before cooking?

Partial thawing is recommended for greens frozen as a solid block. The NMSU publication says that “Greens should be partially thawed and separated before cooking.” Penn State Extension also notes that most frozen vegetables can be cooked directly from the freezer, so the thawing advice applies specifically to greens frozen as a solid block.

Is canning kale a good alternative to freezing?

Penn State Extension states that freezing is the preferred method for hearty greens because it gives a higher quality product than canning or drying. The sources here do not provide a verified canning procedure for kale, so canning requires a tested USDA or extension guide for that exact food.

Sources

Penn State Extension, “Preserving Greens,” https://extension.psu.edu/preserving-greens (opened 2026-10-27)
University of California Cooperative Extension, “Preserving Spring Greens,” https://ucanr.edu/sites/default/files/2020-10/336592.pdf (opened 2026-10-27)
New Mexico State University Extension, “Freezing Vegetables” (E320), https://pubs.nmsu.edu/_e/E320/index.html (opened 2026-10-27)