1. Using a paring knife, score the peels of the Florida Oranges and lemon into 4 sections lengthwise. Remove the peels and scrape off the white pith. Cut the peels into very thin strips.
2. In a saucepan, combine citrus peels, water and baking soda and bring to a boil. Reduce heat, cover and simmer for 20 minutes. Do not drain.
3. Section the peeled Florida Oranges and lemon over a bowl to catch the juice. Discard the seeds.
4. Add fruit sections and reserved juice to the saucepan and return to boiling. Reduce heat, cover and simmer for 10 minutes or until thick.
5. In a 10 quart Dutch oven, combine 3 cups of the fruit mixture with the sugar and bring to a full rolling boil. Quickly stir in the pectin and return to boiling. Cook and stir, uncovered, for 1 minute. Remove from heat and skim off foam.
6. Immediately ladle the mixture into hot, sterilized half-pint jars, leaving ¼-inch of head space. Adjust lids and process in a boiling-water canner for 15 minutes.
7. Remove from canner and let cool overnight. Marmalade may take up to 2 weeks to set.