Prepare Jars: Wash about 3 (16-ounce) jars or freezer-safe containers thoroughly. Set aside.
Puree Berries: Place the washed strawberries into a blender. Blend until completely smooth and pureed.
Combine & Stir: Pour the pureed strawberries into a large bowl. Add the lemon juice and stir until well combined.
Add Pectin: Slowly sprinkle the pectin into the strawberry mixture, stirring constantly as you add it to prevent clumps. Continue stirring until all the pectin is fully dissolved.
Rest: Let the berry mixture sit undisturbed for 30 minutes.
Heat Jam: After 30 minutes, transfer the berry mixture to a medium saucepan. Add the sugar and light Karo syrup.
Warm Gently: Heat the mixture over medium-low heat, stirring constantly, until it's no longer cold to the touch. A simple test: dip your pinky finger in; if you barely feel the jam, it's ready. Immediately remove from heat. Do not boil.
Fill Jars: Carefully pour the warm jam into your prepared jars or containers.
Cool & Freeze: Allow the jam to cool completely at room temperature. Important: If using glass jars, do not fill them to the very top, and do not screw the lids on tightly before freezing (just rest them on top). Once completely cooled, place the jars in the freezer.
Seal & Store: After 24 hours in the freezer, you can tighten the lids on your jars. Enjoy!