Nicky,
Here's my recipe, and Jersey Lilly said it right. BECAUSE of the acidity of tomatoes, you don't have to use a pressure canner, just water bath. Also as Lilly said, be sure your jars and rings and lids are boiled in water, (at least 15 min).
Here goes:
5 chopped Jalepenos
3 chopped banana peppers
5 small green peppers
3 chopped onions
15 medium tomatoes
2-4 cans tomato paste (until thick enough for your tastes)
1 t white pepper (or to taste)
1 T cumin
1 T garlic powder
2 t salt.
Blanch and peel tomatoes, cut into chunks size of a large marble. Place in large kettle, add jalepenos, banana peppers, green peppers, onions, tomato paste and spices. Heat through but do not cook. Pack hot in sterilized quarts or pints.
I use a pressure canner anyway and just bring up to 15 lb. then take off heat.
Using a water bath I would process for 45 min., because you have other vegetables mixed in that are low in acidity.
Everyone who's tasted my salsa has loved it.
Good luck and happy canning!!!