How to Pressure Can Vegetables Safely at Home

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Pressure canning is the method that the National Center for Home Food Preservation names for vegetables, and it is the first thing a home canner needs to understand before opening a jar of anything low in acid. This guide explains how to pressure can vegetables, what the process depends on, and where the published tables should be checked before you start. It is written for a home cook who owns a pressure canner and wants a clear outline of the steps.

Quick answer

• Vegetables are low-acid foods. The National Center for Home Food Preservation says pressure canning is the only recommended method for canning vegetables.
• Boiling water canners are not recommended for these foods because of the botulism risk.
• Vent the canner for 10 minutes before pressurizing, and check dial gauges for accuracy every year.
• Pressure must rise with elevation. Use the table for your elevation and the process time for your jar size.

Why vegetables need a pressure canner

The main concern with home canned vegetables is Clostridium botulinum. The National Center for Home Food Preservation states that the bacterium is destroyed in low-acid foods when they are processed at the correct time and pressure in pressure canners. The same source says that using boiling water canners for these foods poses a real risk of botulism poisoning.

That is why canning guidance separates foods by acidity. Plain vegetables such as green beans, corn, carrots, and mixed vegetables are low-acid foods, so the boiling water method that works for some fruits and pickled products is not the method to use for them. A pressure canner raises the internal temperature above the boiling point of water, and that higher temperature is what the process depends on.

A sealed jar can look normal even when it is unsafe. The NCHFP explains that if botulism bacteria survive and grow inside a sealed jar, they can produce a poisonous toxin, and that even a taste of food containing this toxin can be fatal. Following the published process matters more than the appearance of the finished jar.

Botulism and the boiling step

Many people have heard that boiling food is enough to make it safe. The NCHFP addresses that idea directly. It says that boiling food for 10 minutes at elevations below 1,000 feet should destroy the toxin when it is present. That statement is about destroying a toxin that has already formed, and it does not replace a correct process for low-acid food. The same source gives a clear recommendation: discard any home canned food that might contain botulism toxin.

For this reason, the process that prevents the bacteria from surviving in the jar is the one that matters. Pressure canning is the method that the guidance uses to achieve that outcome for vegetables.

What you need before you start

Before you begin, confirm three things about your equipment. First, confirm the canner is a pressure canner, not a large stockpot. Second, read the manufacturer’s instructions for the specific model, especially how the weighted gauge or dial gauge should behave when the right pressure is reached. The USDA guidance on weighted gauges says to read the manufacturer’s directions to learn how the gauge should rock or jiggle to show that the proper pressure has been reached and is then maintained during processing.

Third, check the dial gauge. The NCHFP recommends that dial gauges be checked for accuracy each year before use. Doing this check at the start of each season is a simple way to make sure the gauge matches the pressure the tables call for.

Gather jars, new lids, and a jar lifter. Wash the jars and keep them hot until filling. Follow the instructions for the specific lids you are using.

Packing vegetables for the jar

The vegetable instructions in the NCHFP mixed-vegetables guide tell the cook to combine all vegetables in a large pot or kettle and add enough water to cover the pieces. That step prepares the mixture before it goes into the jars. Liquid is part of the process because it helps heat reach the center of the jar during processing, and the tables assume that the liquid covers the pieces.

Pack the vegetables into the jars at the headspace listed for each food in the tables, and remove trapped air before sealing. Wipe the rim, place the lid and band, and follow the directions for your lids. Headspace matters because too little or too much can affect sealing and the amount of liquid left in the jar after processing.

Venting and building pressure

Start with the lid closed and the canner’s water at the depth the manufacturer specifies. Heat the canner until steam comes out of the vent port in a steady stream. The USDA guidance says that, to be safe, all pressure canners must be vented 10 minutes before they are pressurized. Venting clears air from the canner so the pressure reading reflects steam and not trapped air.

Once the canner is vented, place the weight or close the petcock as the model requires, and let the pressure rise to the level in the table for your elevation. Start the processing timer only after the canner reaches the target pressure. Keep the pressure at that level for the full process time in the table.

Adjust pressure for your elevation

Water boils at a lower temperature as elevation rises, so a canner must run at higher pressure to reach the same internal temperature. The NCHFP states that canners must be operated at increased pressures as the elevation increases. The mixed-vegetables table shows this for dial gauge canners. For pints and quarts at 0 to 2,000 feet, the table lists 11 pounds of pressure. For 2,001 to 4,000 feet it lists 12 pounds, for 4,001 to 6,000 feet it lists 13 pounds, and for 6,001 to 8,000 feet it lists 14 pounds.

The same table shows that weighted gauge canners work differently. A weighted gauge is set at fixed pressures, so the table lists 10 pounds up to 1,000 feet and 15 pounds above that elevation. Because a weighted gauge cannot be adjusted in small steps the way a dial gauge can, the elevation rule is stated differently.

Do not borrow the pressure from another table or from a different food. Confirm your elevation, choose the correct gauge type, and use the row that matches your jar size and food.

Process times for mixed vegetables

For the NCHFP mixed-vegetable mixture, the process time is 75 minutes for pints and 90 minutes for quarts. Process times are not the same for every vegetable, so the mixed-vegetable time should not be used for a single vegetable without checking that vegetable’s own entry in the current tables.

The published tables list the pressure by elevation in one column and the time in another, so read across the row that matches both your jar size and your elevation. Write the chosen values on a card near the canner so you do not have to rely on memory during a long batch.

Common mistakes to avoid

• Using a boiling water canner for plain vegetables. The NCHFP recommends pressure canning for vegetables.
• Skipping the 10-minute vent. The USDA guidance says all pressure canners must be vented 10 minutes before they are pressurized.
• Using a dial gauge that has not been checked that year. The NCHFP recommends an annual check before use.
• Starting the timer before the canner reaches pressure.
• Using the sea-level pressure at a higher elevation. Canners must be operated at increased pressures as elevation increases.
• Assuming that boiling a jar for 10 minutes makes an unsafe low-acid food safe. The NCHFP recommends discarding any home canned food that might contain botulism toxin.

Where to find tested guidance

For a specific vegetable, look for the entry in the current tables from the National Center for Home Food Preservation. A family recipe or an old handwritten card may not match current tested times. For a related method that uses a different process, see how to pickle green beans, and for a guide to the same vegetable in a different preservation method, see how to can green beans.

Extension offices can help with questions about your altitude, gauge testing, or a food that is not covered in the main tables. Ask before you try a new mixture, because a combination of foods may need a process that is not the same as either food alone.

How we chose

The three pages used here are all from the National Center for Home Food Preservation. Each was opened on 2026-10-27 and each contains text that addresses a separate part of the process: the reason for pressure canning, the equipment and venting steps, and the process times and elevation table. Commercial product pages were not used, and no product recommendations are made.

What we could not verify

The pages above give the process for mixed vegetables and general rules for pressure canners. They do not give a separate process time for each vegetable, so this article does not list times for green beans, corn, or carrots.

What the sources do not say

The sources fetched for this article do not state a rule for how long a jar rests after processing, how to check a seal, or what to do if pressure falls during processing. Those steps are left to the canner manual and the current tables. The sources also do not address altitudes above 8,000 feet in the mixed-vegetable table.

Frequently asked questions

Can I use a boiling water canner for green beans?

The NCHFP says that vegetables are low-acid foods and that pressure canning is the only recommended method for canning them. Boiling water canners pose a botulism risk for these foods, so the published guidance is to use a pressure canner.

Why does my canner need to vent for 10 minutes?

The USDA guidance says that all pressure canners must be vented 10 minutes before they are pressurized. Venting removes air from the canner so the pressure reading reflects the steam inside.

How often should I check my dial gauge?

Once a year, before the season starts. The NCHFP page on pressure canners says dial gauges should be checked for accuracy each year before use, because an accurate gauge is needed to hold the pressure the tables specify.

Do I need more pressure at a higher elevation?

Yes. The NCHFP states that canners must be operated at increased pressures as elevation increases. The mixed-vegetable table lists higher pressure in each elevation band for dial gauge canners.

Can I use one process time for every vegetable?

No. The process time for mixed vegetables is 75 minutes for pints and 90 minutes for quarts, and other vegetables have their own times. Check the entry for the exact food and jar size.

Sources

• National Center for Home Food Preservation, “For Safety’s Sake,” https://nchfp.uga.edu/how/can/general-information/for-safetys-sake/ (opened 2026-10-27)
• National Center for Home Food Preservation, “Using Pressure Canners,” https://nchfp.uga.edu/how/can/general-information/using-pressure-canners/ (opened 2026-10-27)
• National Center for Home Food Preservation, “Mixed Vegetables,” https://nchfp.uga.edu/how/can/canning-vegetables-and-vegetable-products/mixed-vegetables/ (opened 2026-10-27)