How to Save Watermelon Seeds

Whether you’ve purchased a tasty and favorite seeded watermelon (Citrullus lanatus) from your local market or grown it from purchased seeds, it’s possible to save the melon’s seeds to grow the next season. This not only saves you some cash but also makes a fun project to help get the kids enthused about growing things. Saving watermelon seeds is easy and the steps are basic, and we give you all the tips for seed-saving success.


Know When the Watermelon is Ripe

Watermelons are a warm-season crop that can takes months to achieve the ripe stage where the fruits are ready for harvesting. Depending on the cultivar, watermelons can be ready for picking in around 60 days, or take over 100.

Check the seed packet where it lists “days to harvest” to get an approximate idea of when you can expect your particular watermelon to ripen. Saving seeds from a ripe watermelon offers the best germination success.

Although the days to harvest gives a good idea of when you can expect to pick a ripe melon, there are other signs that signify your watermelon is ripe and ready for picking. Remember, once harvested, an unripe watermelon won’t continue to ripen any further. Once you determine the watermelon has achieved the prime stage of ripeness, simply cut the melon off the vine.

Signs a watermelon is ready for harvesting include:

  • The curly tendrils on the stem where attached to the watermelon change from light green to brown and become dry.
  • The watermelon’s appearance changes from shiny to dull.
  • You can’t penetrate the outer skin with a thumbnail.
  • The bottom portion of the melon that touched the ground changes from green to yellowish.
  • The heavier the watermelon, the riper it is.

Expert Gardener Tips:  Although an old wives tale says you can determine if a watermelon is ripe by “thumping” it, don’t rely on this test or you can end up disappointed. Some varieties of watermelons won’t have a dull thud and you can end up with an overripe and mushy melon.

Steps for Saving Watermelon Seeds

Of course, the first step in saving watermelon seeds is cutting open the melon, sinking your teeth into the sweet and juicy flesh and enjoying a bit of summer heaven. Nothing is quite as refreshing on a hot summer day like biting into a slice of cold, thirst-quenching watermelon.

While you are enjoying your summer treat, simply spit the seeds onto a napkin or cup. Once you finish your succulent treat, you then can prepare the seeds for saving.

  1. Wash the watermelon seeds to remove any flesh clinging to them.
  2. Spread the clean seeds out on a paper towel and allow them to completely dry for a day or two. Don’t store seeds that are still moist or they can mold, which shortens their life and affects germination.
  3. Place the dry seeds in an airtight container like a plastic one with a tight-fitting lid or plastic bag.
  4. Note on the container the watermelon’s cultivar name, expected days to harvest and the date the seeds were saved.
  5. Store the container in a cool, dry area until planting time the following spring.

Expert Gardener Tip:  Properly stored watermelon seeds should remain viable for approximately four years. The most important thing when it comes to saving watermelon seeds is keeping them dry and cool.