Prepare water bath canner and essential equipment including mason jars, lids, and rings.
Thinly cut all lemon peel from one lemon and cover with water in a small pot and boil for 5 minutes. Save lemon pulp for later.
Drain lemon peels and add them to the crushed strawberries, pectin, and lemon juice from leftover pulp to a large stockpot. Stir and slowly bring to a boil and then add sugar. Stir constantly and dissolve all sugar.
Bring back to a rolling boil for one hard minute, stirring constantly. Remove from heat and skim off any foam. Be sure to take off heat otherwise foam will keep forming.
Ladle hot marmalade into hot jars, leave ¼ inch headspace, wipe rim, and adjust lids and rings. Process in water bath canner for 10 minutes.
Take out of canner and let sit for 24 before taking off rings or moving. Make sure lids have popped and sealed properly.