Wash the plums and gather your canning supplies while the plums dry. See the instructions for “How to make and Can Strawberry jam” for basic canning instructions.
Cut the plums into small pieces, removing the seed. Once all of the plums are cut, place in a 6-8 quart stock pot on the stove top.
Mix in the lemon juice, cardamom and then whisk in the Sure-jell.
Heat over medium high heat on the stove top until the plums come to a full rolling boil that can’t be stirred down.
Add the sugar all at once and continue to heat on medium high until it comes to a full rolling boil again.
Once boiling time for 1 minute and then remove from the heat.
Skim off any foam that accumulates.
Place into hot half pint jars allowing ⅛ inch head space.
Can in water bath for 10 minutes.