Hi Mary, 

To can tomato sauce at home, you have a few different tested recipes to choose from. We have several options in our guide to canning tomatoes, and you can also find good recipes on the Ball website. 

If you want to can a straight tomato sauce without additional vegetables, you can follow the Tomato Sauce recipe from our publication and from the National Center for Home Food Preservation. It calls for simmering down your tomatoes to reduce the volume to about one-half of the original volume, pressing through a sieve to remove skins and seeds, then adding 1 Tablespoon of lemon juice per pint jar (2 Tbsp per quart) and processing in a boiling water canner. 35 minutes for pints, 40 minutes for quarts, with longer times needed at higher elevations. It is not safe to add onion or garlic to this recipe before canning.

If you want to add vegetables, you will need to switch to a pressure canning recipe like the Spaghetti Sauce without Meat recipe. You can add up to a cup of onions and five cloves of garlic in this recipe if you are starting with 30 lbs of tomatoes. This recipe does not require adding lemon juice, but it must be processed in a pressure canner to have a safe product. Pints process for 20 minutes, and quarts process for 25; make sure to use the correct pressure based on your elevation. 

Because improperly canned tomatoes and tomato sauces can be a risky food for botulism poisoning, it's very important that you follow the quantities in a tested recipe and do not add more vegetables to taste. Youi can always freshen up your sauce with new ingredients after you open the jar for cooking!

Thanks for using Ask Extension.

Jared