Tomatoes from frost-killed vines are not for canning 

As the weather turns cooler and overnight temperatures dip, you may find yourself scrambling to pick the last of your tomato crop. If a frost kills the vines before you get to them all, are the remaining fruits safe for canning? The short answer is no.

Tomatoes from frost-killed or dead vines can be too low in acid to be safely canned. These tomatoes are not the only ones unsuitable for canning. Over-mature, decayed, damaged, or moldy tomatoes can also be too low in acid, and they may have a higher likelihood of carrying bacteria, making them unsafe for canning.

When canning tomatoes:

• Choose fresh, firm, healthy, and preferably vine-ripened fruits
• Always acidify tomatoes, even when pressure canning
• Follow a scientifically validated recipe, and follow the instructions exactly

For further information, check the National Center for Home Food Preservation (NCHFP) website at nchfp.uga.edu or contact your local Cooperative Extension office.
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Brought to you by the UCCE Master Food Preservers of El Dorado County
Article last updated, July 2025