1In a large bowl, add the rhubarb and sugar; stir to coat evenly.
2Cover the bowl, and place it in the refrigerator overnight.
3The next morning, place the rhubarb mixture and the strawberries, in a large kettle.
4Bring the mixture to a boil over medium heat, then lower the heat just a bit, and gently boil for 15 minutes (stirring constantly).
5Add the crushed pineapple, and cook for an additional 5 minutes.
6Turn off the stove, add the boxes of dry gelatin powder, and mix well.
7Transfer the jam to the sterilized glass jars, and cover the jars with the lids.
8Cool the jam to room temperature, before storing it in the refrigerator or freezer.
9Note: If using store bought frozen sweetened strawberries, you may want to decrease the amount of sugar to 3-1/2 cups. I however, used strawberries which I prepared myself and had froze them. They're not as sweet as the store bought, so the 4 cups of sugar I added, was the right amount to add to this recipe.