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Can zucchini be canned in jars?

Zucchini is a popular summer squash that can be enjoyed fresh or preserved for enjoyment throughout the year. Many home cooks wonder if zucchini can be canned in jars for long-term storage. The answer is yes, with proper preparation and processing, zucchini can be safely canned in jars.

Can You Water Bath Can Zucchini?

When canning any vegetable, there are two main methods – water bath canning and pressure canning. Water bath canning involves submerging sealed jars in boiling water for a specified period of time. This heating process destroys microorganisms and enzymes that could cause spoilage. However, water bath canning is only recommended for high-acid foods like fruits, jams, jellies, and pickles. Since zucchini is a low-acid vegetable, it is not recommended to water bath can zucchini. The temperature of a water bath is not high enough to kill bacterial spores that cause botulism, a potentially fatal foodborne illness. For this reason, zucchini and other low-acid vegetables must be processed using a pressure canner to reach the higher temperatures needed for safe long-term preservation.

Step-by-Step Instructions for Canning Zucchini in a Pressure Canner

Follow these steps for safely canning zucchini in a pressure canner:

  1. Wash and trim zucchini, cutting into 1/2 inch slices, cubes, or lengths. Keep the peel on or peel if desired.
  2. Blanch zucchini pieces in boiling water or steam for 3 minutes. This helps soften texture and lock in color and flavor. Drain and rinse with cool water.
  3. Pack blanched zucchini tightly into clean Mason jars, leaving 1 inch of headspace. Add salt if desired, allowing 1/2 tsp per quart. Do not add any liquid to the jars.
  4. Wipe jar rims with a clean, damp cloth. Apply lids and screw bands fingertip tight.
  5. Process pint or quart jars of zucchini in a pressure canner at 11 PSI for 25 minutes for pints, 30 minutes for quarts. Consult the manufacturer’s directions for your specific pressure canner model.
  6. When processing time is complete, allow pressure to naturally drop to 0 before carefully removing jars. Avoid tilting or jostling jars.
  7. Let jars cool undisturbed for 12-24 hours. Check jar seals, then store in a cool, dark place for up to a year.

Always use current, tested canning recipes and follow directions precisely for safe results. Only process in a dial or weighted gauge pressure canner in good working condition.

Tips for Canning Zucchini

  • Choose young, firm, tender zucchini for best texture and flavor.
  • Trim ends and wash well but don’t peel before slicing.
  • Cut into uniform pieces for even heating during processing.
  • Blanching before packing helps zucchini hold shape and seals in taste.
  • Only fill jars with raw zucchini pieces, no added liquid.
  • Process at 11 PSI, adjusting for your altitude if needed.
  • Let jars seal and rest undisturbed before storing.
  • Check seals before storage, reprocess any unsealed jars.
  • Store in a cool, dark place between 50-70°F for up to 1 year.

How to Tell if Canned Zucchini is Safe to Eat

Properly canned zucchini stored under optimal conditions can safely stay sealed on the shelf for 12 months. Here are signs to look for when inspecting jars of canned zucchini:

  • Lid is concave and does not move when pressed. This indicates a good vacuum seal.
  • Nothing is leaking from the jar. Look for any signs of seepage around the rim or lid.
  • Jar and lid have no rust or damage. Small dents and nicks are ok as long as the seal is still intact.
  • Product looks normal inside the jar, with no mold, sliminess, or foul odors when opened.
  • Liquid levels are normal, with no signs the product has spoiled and caused the jar to bulge.

As long as the jar lid seal is vacuumed and intact, canned zucchini is safe to eat for up to a year past processing. When opening a properly sealed jar, the lid should make a popping noise as the vacuum is released. If you notice any signs of spoilage upon opening, do not consume the zucchini and discard the entire jar.

What Happens if Canned Zucchini Goes Bad?

If canned zucchini is not processed and stored correctly, it can spoil or even become unsafe to eat. Here are some common signs of spoilage:

  • Lid bulge or loose seal
  • Cloudy liquid in the jar
  • White sediment at the bottom of the jar
  • Slimy texture or foul odor
  • Black or dark spots on zucchini pieces
  • Gas bubbles
  • Mold growth

Do not taste or eat any zucchini that shows these signs of spoilage. Botulism toxin can be present even if there are no visible signs, so zucchini with a compromised or bulging lid should be discarded as well. When in doubt, throw it out.

How to Use Canned Zucchini

Canned zucchini retains a crunchy texture and mild flavor similar to fresh zucchini. It can be used in all the same ways you would use fresh:

  • Sauté into stews, soups, and stir fries
  • Add to casseroles, lasagnas, and baked pasta dishes
  • Make into quick breads, muffins, and cakes
  • Blend into hummus or veggie dips
  • Top pizzas, bruschetta, and flatbreads
  • Simmer into chili, tacos, enchiladas, and pasta sauce

Canned zucchini is already cooked so it just needs to be briefly reheated before using in recipes. The blanching process before canning helps soften the texture so it requires less cooking time than raw fresh zucchini.

Nutrition Facts of Canned vs. Fresh Zucchini

Canning does result in some vitamin loss compared to fresh vegetables, but canned zucchini still provides beneficial nutrition:

Nutrient Fresh Zucchini Canned Zucchini
Calories 20 per 1 cup 17 per 1 cup
Vitamin C 28% DV 14% DV
Vitamin A 5% DV 4% DV
Folate 7% DV 6% DV
Potassium 8% DV 5% DV
Fiber 1g 1g

Canned zucchini is low in calories, has zero fat, and provides folate, potassium, vitamin C, and fiber. Choose canned zucchini packed in water or low sodium broth to keep the sodium content down.


With proper pressure canning technique, zucchini can be safely preserved in jars for enjoyment long after the summer harvest ends. Follow trusted canning recipes carefully to prevent risk of spoilage or foodborne botulism. Canned zucchini has a useful shelf life of 1 year when stored in a cool, dark place with the vacuum seal intact. Always inspect jars closely before consuming and discard any that show signs of mold, bulging lids, or spoilage. Properly home canned zucchini has a pleasant flavor and texture that works well in many recipes in place of fresh zucchini.