Wash and hull the strawberries, then crush them using a potato masher or a fork.

In a large saucepan, combine the crushed strawberries, sugar, and lemon juice.

Heat the mixture over medium heat, stirring constantly until the sugar is completely dissolved.

Increase the heat to high and bring the mixture to a rolling boil.

Add the pectin and continue to boil for 1 minute, stirring constantly.

Remove the saucepan from heat and skim off any foam that has formed. Allow the jam to cool slightly before pouring it into sterilized jars. Seal the jars and store them in a cool, dark place.