When you are pressure canning vegetables, you can do mixed batches inside a jar.
Processing method: Pressure canning only
The processing time for a mixture is that required for the longest vegetable
The Ball Blue Book (37th edition, page 98) gives the following rule of thumb for doing this:
The length of processing time for combination recipes must safely preserve the ingredient requiring the longest processing time. Follow individual recipe for ingredient preparation, jar size and processing time.”  Ball Blue Book. Muncie, Indiana: Healthmark LLC / Jarden Home Brands. Edition 37. 2014. Page 98
So Easy to Preserve says,
Unless a tested recipe is used, all tomato-vegetable mixtures must be processed in a pressure canner, according to the directions for the vegetable in the mixture that has the longest processing time.” Andress, Elizabeth L. and Judy A. Harrison. So Easy to Preserve. University of Georgia Cooperative Extension. Bulletin 989. Sixth Edition. 2014. Page 59.
Barb Ingham at the University of Wisconsin says,
You may create vegetable mixtures as long as there is a tested recipe for each vegetable that you are combining and you follow the processing time for the vegetable that has the longest time listed.”  Ingham, Barb. Play it safe when preserving vegetables. University of Wisconsin Extension Blog. 29 June 2015.
To clarify, this means that:
If you put in the same 1/2 litre (US pint) jar green beans (requiring 20 minutes processing) and carrots (requiring 25 minutes processing), the jar must be processed for 25 minutes. The longest processing time (for the carrots in this case) becomes your time for the combined jar.
It also means that you cannot include vegetables that *don*t* specifically have pressure canning procedures from a recognized source, such as the USDA, a University Extension, or a Jarden company such as Ball or Bernardin. That means no eggplant, no cauliflower, etc. And strictly speaking, that also means no celery in your mixtures as there are no separate processing procedures authorized for that, either.
A clove of garlic is an exception, however. Barb Ingham at the University of Wisconsin says it’s fine to add 1 clove of garlic per jar, if desired:
You may add a small amount of garlic (up to 1 clove per jar) to canned vegetables without impacting the processing time.”  Ingham, Barb. Play it safe when preserving vegetables. University of Wisconsin Extension Blog. 29 June 2015.
Note that the default pressure is always 10 lbs — you adjust adjust the pressure for your altitude if you are over 300 metres (1000 feet).
Choose vegetables close in processing time for quality reasons
When you are choosing vegetables to mix, you usually want to pick vegetables that are relatively close together in processing times, and vegetables that won’t affect the flavour of their jar mates. This is a quality decision, rather than a safety decision.
For instance, green beans and carrots are close in processing time, and their taste doesn’t affect each other.
Carrots and asparagus are also similar in processing time, but the taste of the asparagus might infuse into the carrots.
A litre (US quart) sized jar of potatoes requires 40 minutes of processing in a pressure canner; the same size jar of green beans would be 25 minutes. A combined jar of the two would require the 40 minutes for the potatoes. It’s your judgement call if the additional 15 minutes of processing that would be required for the green beans would affect their quality too much for your preferences in that particular mix. (Just to be clear, the 40 minutes for the potato and green beans mixture would *not* be a judgement call, it is required. Whether to do that combination in the first place is your judgement call.)
Barb Ingham at Wisconsin says,
You’ll have much higher quality product if you can mixtures with similar processing times. Consider the canning time for a mixture of carrots (30 minutes); corn (85 minutes); green peas (40 minutes); onions (40 minutes) and potatoes (40 minutes) in quart jars. This mixture must be canned 85 minutes, by which time some of the vegetables will be severely over-processed. Leaving out the corn will drop the processing time to 40 minutes, with higher quality results. Adding meat to the mixture (beef or chicken) will lengthen the processing time by 5 minutes, to 90 minutes for quart-size jars.”  Ingham, Barb. Canning mixtures. University of Wisconsin Extension Blog. 11 August 2015.
Note she mentions that you can even add meat to the mixture (though an amount is not suggested.)
Mixtures can depend on harvest times, too
Barb Ingham goes on to note that when certain veg are in season will affect your decision about what to mix:
There are times when canning a mixture just don’t make sense because the individual vegetables have very different harvest times. Harvesting peas in June and holding them (refrigerated) until August when corn and potatoes are harvested will result in a poor quality mixture as the peas turn starchy and lose nutrients during storage.”  Ingham, Barb. Canning mixtures. University of Wisconsin Extension Blog. 11 August 2015.
And remember, harvest times don’t affect just the grow-your-own crowd, either: it also affects those who buy their produce when it’s at its cheapest each year in the markets.
Some people make the continuing mistake in thinking that tomatoes have enough acidity in them to make other vegetables put in with them safe. As we’ve seen elsewhere, that was disproved years ago — both in a lab, and in hospital emergency wards. Tomatoes actually can’t even be assumed to have enough acidity to make themselves safe, let alone anything else.
If you make up a mixture of tomatoes and vegetables, it has to be processed in a pressure-canner, and, processed for the time for the longest ingredient.
- If you essentially “pickle” the mixture by adding enough acidity, as happens in the approved salsa recipes. Then the mixture is water-bathed or steam-canned;
- In USDA and Extension lab-tested recipes for pressure-canned tomato and vegetable mixtures, some total processing times may be less than the longest ingredient time — that’s because strict lab-testing was done on those exact recipes to confirm that a shorter processing time would do the trick.
- The Minnesota Mixture from Minnesota Extension is a tomato / vegetable mixture that was designed for water-bath canning.
Clemson Cooperative Extension says,
Unless a tested recipe is used, all tomato-vegetable mixtures must be processed in a pressure canner, according to the directions for the vegetable in the mixture that has the longest processing time. Tomato-vegetable mixture recipes in this fact sheet may have shorter processing times because they have been tested for both pH and heat penetration. When the exact amounts specified in these recipes are used, these mixtures can be processed using the times given.”  P.H. Schmutz and E.H. Hoyle. Preserving Tomato Products. Clemson Cooperative Extension. Revised August 2007. Accessed March 2015.
Standard pre-set vegetable mixtures
There are three, standard pre-set vegetable mix recipes that we know of. One is from the USDA; another from So Easy to Preserve, and the other is from Jarden (Ball and Bernardin.)
Note that these three mixes are the only canning methods we’re aware of for plain zucchini (aka courgette), unless you pickle it. (Decades ago, there were separate recommendations but they were withdrawn for safety reasons.)
Note that Ball calls for any zucchini to be peeled; the USDA and So Easy to Preserve don’t.
And remember of course, that the lb pressure in all the recipes below must as usual be adjusted for your altitude.
USDA Mixed Vegetables
Source: Mixed Vegetables: In: United States Department of Agriculture (USDA). Complete guide to home canning. Agriculture information bulletin No. 539. 2015. Page 4-12.
- 6 cups sliced carrots
- 6 cups cut, whole kernel sweet corn
- 6 cups cut green beans
- 6 cups shelled lima beans
- 4 cups whole or crushed tomatoes
- 4 cups diced zucchini
Optional mix – You may change the suggested proportions or substitute other favorite vegetables except leafy greens, dried beans, cream-style corn, winter squash and sweet potatoes.
Yield: 7 quarts
Procedure: Except for zucchini, wash and prepare vegetables as described for carrots, corn, lima beans, snap beans or italian beans and tomatoes. Wash, trim, and slice or cube zucchini; combine all vegetables in a large pot or kettle, and add enough water to cover pieces. Add 1 teaspoon salt per quart to the jar, if desired. Boil 5 minutes and fill jars with hot pieces and liquid, leaving 1-inch headspace.
Pressure: 10 lbs (Adjust for altitude)
1/2 litres (US Pints): 75 minutes
1 litre (US Quarts): 90 minutes
(Consult full version here.)
So Easy to Preserve Mixed Vegetables
Select your favourite mixture of vegetables, except greens, dried beans, cream-style corn, summer or winter squash, or sweet potatoes. Equal portions of carrots, whole kernel sweet corn, cut green beans, lima beans, crushed tomatoes and cubed zucchini make a good mix. Except for zucchini, prepare each vegetable as for canning and cut into the desired shapes. Wash, trim and dice zucchini if used. Mix all vegetables together, add enough boiling water to cover pieces, and bring back to a boil. Boil 5 minutes. Fill hot vegetables into hot jars, leaving 1 inch (2 cm) headspace. Add 1/2 teaspoon salt to pints (1/2 litres); 1 teaspoon to quarts (litres), if desired. Fill jars to 1 inch (2 cm) from top with boiling water. Remove air bubbles. Wipe jar rims. Adjust lids and process. Dial Gauge 11 lbs, Weighted Gauge 10 lbs [Ed: Adjust both for altitude.] Pints 75 minutes, quarts 90 minutes.”  Andress, Elizabeth L. and Judy A. Harrison. So Easy to Preserve. University of Georgia Cooperative Extension. Bulletin 989. Sixth Edition. 2014. Page 91.
Note that you can include onion, if you follow the procedure for onion on page 92 of So Easy to Preserve.
Ball Blue Book Mixed Vegetables
Source: Mixed Vegetables. In: Ball Blue Book. Muncie, Indiana: Healthmark LLC / Jarden Home Brands. Edition 37. 2014. Page 113.
(Redacted version for the sake of comparison brevity).
- 3 1/2 cups carrots peeled and sliced 1/4 inch thick
- 3 1/2 cups (14 oz) corn niblets (from about 7 medium cobs)
- 3 1/2 cups (about 6 pounds) shelled lima beans (butter beans)
- 3 cups zucchini peeled and cut into 1/2 inch cubes
- 1 cup (1 large) sweet red pepper chopped into 1/2 inch pieces
Combine prepared vegetables in a large stainless steel saucepan; add water to cover. Boil vegetables 5 minutes. Pack in 1/2 litre or litre jars. Fill with hot water, leaving 2 cm (1 inch) headspace.
Pressure: 10 lbs (Adjust for altitude)
1/2 litres (US Pints): 75 minutes
1 litre (US Quarts): 90 minutes
(Note: Bernardin Guide 2013, page 103 gives the same recipe as Ball, except doubled, but like the USDA does not call for the zucchini to be peeled.)
Combine when serving instead?
Don’t forget, you can always combine when serving!
Barb Ingham at Wisconsin says that’s what she prefers to do — mix when serving.
Instead of canning mixtures, I prefer to can individual vegetables (in pint-size jars). This allows me to harvest vegetables as their peak and avoid over-processing. When it’s time to make a meal, I combine a variety of pint jars …. ”  Ingham, Barb. Canning mixtures. University of Wisconsin Extension Blog. 11 August 2015.
If you can separately and mix when serving, you have infinite flexibility.
In 1944, the USDA said NOT to can any combined vegetable mixtures.
Ongoing home canning research since then has enabled the mixtures that we covered above.
Ingham, Barb. Play it safe when preserving vegetables. University of Wisconsin Extension Blog. 29 June 2015.
Ingham, Barb. Canning mixtures. University of Wisconsin Extension Blog. 11 August 2015.
References [ + ]
|1.||↑||Ball Blue Book. Muncie, Indiana: Healthmark LLC / Jarden Home Brands. Edition 37. 2014. Page 98|
|2.||↑||Andress, Elizabeth L. and Judy A. Harrison. So Easy to Preserve. University of Georgia Cooperative Extension. Bulletin 989. Sixth Edition. 2014. Page 59.|
|3, 4.||↑||Ingham, Barb. Play it safe when preserving vegetables. University of Wisconsin Extension Blog. 29 June 2015.|
|5, 9.||↑||Ingham, Barb. Canning mixtures. University of Wisconsin Extension Blog. 11 August 2015.|
|6.||↑||Ingham, Barb. Canning mixtures. University of Wisconsin Extension Blog. 11 August 2015.|
|7.||↑||P.H. Schmutz and E.H. Hoyle. Preserving Tomato Products. Clemson Cooperative Extension. Revised August 2007. Accessed March 2015.|
|8.||↑||Andress, Elizabeth L. and Judy A. Harrison. So Easy to Preserve. University of Georgia Cooperative Extension. Bulletin 989. Sixth Edition. 2014. Page 91.|