How to Can Zucchini (Summer Squash)

Canning zucchini is just one way to save that summer squash for later on in the season.

Before I share the instructions for canning zucchini, I need to share some very important information.

Read This Before You Proceed:

The method that I use for canning zucchini is a tried and true recipe and originally came from the Ball Blue Book.

If you look at the National Center for Home Food Preservation website, they do not recommend canning summer squash because of lost documentation and uncertainty in processing times.

Before you decide to can zucchini, do some homework and determine for yourself if you feel this is a safe food preservation process.

What You Need, to Can Zucchini:

• fresh zucchini
• knife & cutting board
• salt (optional)
• A pot of water to cook zucchini (or a steamer)
• large pot of boiling water
• canning jars (pint or quart)
• pressure canner
• canning tools (ladle, bubble wand, lid magnet, jar tongs, etc.)
• kitchen towels
• damp cloth or paper towel
• pot holders
• bowl of hot water (to heat lids – never boil lids)

Preparing to Can

To can zucchini, you will begin by preparing your canning jars, canning supplies, and your pressure canner.

Your jars should be clean and inspected for any chips or flaws prior to use. Place the jars in your canner and add 2-3 inches of water. Turn on your stove, so that the jars are nice and hot. You don’t need the water to be boiling or you will need to add additional water before you begin processing. The jars just need to be hot.

You do not have to sterilize jars when pressure canning.

Line a work space with a folded kitchen towel to prevent temperature shock when you place the hot jars on the counter to fill them.

Zucchini is a low acid food and can NOT be canned in a hot water bath canner or a steam canner.

Article: How to Use a Steam Canner

How to Can Zucchini

To begin, you will wash your zucchini.

Trim the ends off, then cut the zucchini into cubes, do not peel it.

Boil or steam the zucchini for 2-3 minutes.

Pack the hot zucchini into the canning jars (pint or quart.) Leave a 1 inch head space.

For pint jars, add 1/2 teaspoon of salt, for quart jars you will add 1 teaspoon. Adding the salt is optional.

Ladle boiling water over the vegetables, leaving an inch of headspace.

Use a bubble wand to remove any air bubbles.

Wipe the rim with a damp cloth and place a lid and ring on the jar. Close the jar finger tight.

Place the jars in your canner as you fill them. I generally just have 2 or 3 jars out at a time, so that they stay hot. Fill those, place them in the canner, and take out the next jars to fill.

Place filled jars on the jar rack in the canner, using a jar lifter/tongs as you fill them. When you are moving the jar, make sure the jar lifter is securely positioned below the neck of the jar (below the ring band of the lid) that way you don’t inadvertently shift the lid in any way. Keep the jar upright. Tilting the jar could cause food to leak into the sealing area of the lid, causing your jars not to seal properly.

Processing the Jars

Close and seal the canner lid securely. Leave the weight off the vent pipe (or open the petcock – depending upon your model.)

Turn the heat setting all the way to high. Heat the canner until the water boils and steam flows steadily in a funnel-shape from the open vent pipe or petcock. Let the steam flow (exhaust) continuously for 10 minutes. This makes sure that your canner is fully heated before you really start.

Place the counterweight or weighted gauge on the vent pipe or close the petcock. The canner will begin pressurizing in the next few minutes.

Once your canner has reached the appropriate pressure (See below), start the timer. (If your canner does not have dial gauges, then when the weighted gauge begins to jiggle or rock as the manufacturer’s instructions describe.)

Canning Time and Pressure

• Pint jars – process for 30 minutes
• Quart jars – process for 40 minutes

This recipe processes at 10 pounds pressure for elevations of 0 – 1000 feet.

For elevations of 1,001 – 10,000 feet, the pressure is 15 pounds.

Regulate the heat on your stove to maintain a steady pressure at, or slightly above, the correct gauge pressure. 

I am in the 0 – 1,000 feet elevation and try to keep the pressure right at 11 pounds. I do this so that if there is any fluctuation, I have time to adjust it before it drops below the 10 pound level.

If at any time your pressure drops below what it should be, you have to stop your timer, bring the pressure back up, and start the time over at the beginning.

Finishing Up your Canned Zucchini

Once the canner has finished depressurizing all the way down to zero, (this can take 30-45 minutes or so) let it sit for 2 more minutes. Open the lid, carefully so you do not burn yourself with the steam.

Line your counter or a space (away from drafts) with a couple layers of folded kitchen towel. (You could also use a cooling rack if you prefer.)

Use your jar tongs/lifter to remove the jars from the canner and place them on the folded towels. Leave about an inch of space all around the jars so that they can cool.

Let the jars sit undisturbed for 12 to 24 hours. As they cool, you will hear the lids “tink!” as they seal.

After the jars are cooled (I usually wait until the next day), remove the ring bands from sealed jars. Gently press down on the top of each jar to make sure the lid sealed. If you have any that didn’t seal, stick them in the fridge and use them in the next week or so.

Wash jars and lids to remove all residues. Wash the rings and store them away for another time.

Label your jars (I always put the year in addition to what is in there) and store them in a cool, dry place that is out of direct light.

When the timed process is completed, turn off the stove and, if you can, remove the canner from the heat. If you are unable to move it, that is okay. You just don’t want the jars to jostle or tip over inside.

Let the canner cool down naturally. Do not vent it or try to cool it down faster in anyway, or your jars may not properly seal.

How to Use Canned Zucchini

Canned zucchini is not a substitution for fresh zucchini, but it is a great way to save the excess summer harvest. I really hate for anything to go to waste after all that work to grow it!

The canning process causes the zucchini to get rather soft, so I find that it is best used in recipes like Zucchini Bread.

Simply drain the canned zucchini in a colander and allow it to sit for a few minutes to remove any excess liquid. Then, I purée or mash the zucchini before mixing it into my batter.

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