slices of watermelon on a white table

Watermelon Jam


4.50 from 2 votes
Watermelon Jam is a low-sugar cooked jam made with Pomona’s Universal Pectin. Pomona’s Pectin contains no sugar or preservatives and jells reliably with low amounts of any sweetener.


If you want to make jelly with only the juice of the watermelon, see our Watermelon Jelly recipe.
Servings 5 cups


  • 4 cups watermelon puree use a seedless watermelon or see Step 3 below
  • 4 teaspoons calcium water see step #1
  • ½ cup lemon juice bottled
  • ¾ cup up to 2 cups sugar
  • teaspoons Pomona’s Pectin mixed with sweetener


  • Before you begin, prepare calcium water.
    To do this, combine ½ teaspoon calcium powder (in the small packet in your box of Pomona’s pectin) with ½ cup water in a small, clear jar with a lid. Shake well.
    Extra calcium water should be stored in the refrigerator for future use.
  • Wash jars, lids, and bands. Place jars in canner, fill canner 2/3 full with water, bring to a boil. Turn off heat, cover, and keep jars in hot canner water until ready to use. Place lids in water in a small sauce pan; cover and heat to a low boil. Turn off heat and keep lids in hot water until ready to use.
  • If watermelon is seedless, puree fruit to a pulp in blender or food processor. If watermelon has seeds, remove the seeds prior to pureeing.
  • Measure puree into sauce pan.
  • Add calcium water and lemon juice, and mix well.
  • Measure sugar into a bowl. Thoroughly mix pectin powder into sugar. Set aside.
  • Bring fruit to a full boil. Add pectin-sugar mixture, stirring vigorously for 1 to 2 minutes to dissolve the pectin while the jam comes back up to a boil. Once the jam returns to a full boil, remove it from the heat.
  • Fill hot jars to ¼” of top. Wipe rims clean. Screw on 2-piece lids. Put filled jars in boiling water to cover. Boil 10 minutes (add 1 minute more for every 1,000 ft. above sea level). Remove from water. Let jars cool. Check seals; lids should be sucked down. Eat within 1 year. Lasts 3 weeks once opened.

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19 Responses

  1. Ashley
    | Reply

    Delicious! And came out wonderful. We got an overload of watermelon from the garden all at once this year. The jam is the perfect way to preserve some of it.

  2. Karina
    | Reply

    With pomonas it says you don’t have to add sugar and all.
    Is this possible with watermelon?

    With watermelon could I reduce the watermelon to a thicker consistency before?

    How would you then approach putting pectin / calcium water in recipe?

    • Shelby Collings
      | Reply

      *We don’t recommend making jam or jelly with absolutely no sweetener. The final product is likely to be tart and bland. Sweetener, even in a small amount, brings out the flavor of the fruit.

      If you want to try it, however, this is what you do: For 4 cups of mashed fruit or juice, use either ½ cup water or unsweetened fruit juice (if you’re using 2 or 3 teaspoons of pectin) or ¾ cup water or unsweetened fruit juice (if you’re using 4 teaspoons of pectin).

      Make liquid pectin by measuring the correct amount of water or juice into a small sauce pan and bringing it to a boil. Put boiling liquid in cup for immersion blender, or in food processor, or in blender. Add pectin. It is very important to vent the lid (if there is one) to let steam out. Don’t use an enclosed blender that can’t be vented. Blend for 10 seconds, then stop and scrape down the sides so all pectin clumps are in or on the liquid. Blend for a full minute until all powder is totally dissolved.

      Add the liquid pectin to the boiling fruit or juice mixture, which should already contain the calcium water and lemon juice (or lime juice or vinegar) if called for in the recipe. Stir while mixture returns to a full boil. If you taste your jam before jarring and it isn’t sweet enough, you can add however much sweetener you want at this point. Stir well and return mixture to a boil, remove from heat, jar and process according to the recipe sheet that comes with Pomona’s Pectin.

      These instructions are also on the recipe sheet that comes with your box of Pomona’s Pectin.

  3. Linda
    | Reply

    I have read you can add a small piece of cinnamon stick, is this a tasty addition?

  4. Linda
    | Reply

    Can I double this recipe.

    • Shelby Collings
      | Reply

      You sure can!

  5. Lynn Noel
    | Reply

    Can I substitute maple syrup for the sugar? How much? 1/2 – 1c?

    • Shelby Collings
      | Reply

      Yes, you sure can!

  6. Candace
    | Reply

    Could you substitute finely chopped watermelon rind for the watermelon? Thanks!

    • Shelby Collings
      | Reply

      We cannot say for sure that that would work, as we have never tried it. We believe you would miss a lot of flavor and the texture may be off.

    • Heidi
      | Reply

      I would like to make a watermelon/sweet cherry combo. Can I sub in some pureed cherries for watermelon? And lime juice for lemon and/or add lime zest?

      • Shelby Collings
        | Reply

        Hello Heidi,

        You sure can! Yes, bottled lime juice can be substituted for bottled lemon juice, and lime zest can be added.

  7. Monica Strohhaecker
    | Reply

    How can I add strawberry to this recipe or is there another recipe I can follow for this specific combination?

    • Shelby Collings
      | Reply

      You can certainly add mashed strawberries to this recipe. We would recommend 25/75 or 50/50.

      Happy jamming!

      • Monica Strohhaecker
        | Reply

        Awesome thank you so much!!!!!

  8. april anderson
    | Reply

    Can cantelope be used in place of watermelon in this recipe?

    • Shelby Collings
      | Reply

      Hello April,

      We actually have a yummy Cantaloupe Jam recipe, HERE. Enjoy!

  9. Holly Masters
    | Reply

    What size(s) of jar do you use for this recipe? Thank you!

    • Shelby Collings
      | Reply

      Hello Holly,

      We would recommend 4-8oz jars. Happy jamming!

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