Seed Saving: How to Save Cucumber and Melon Seeds

Introducing Part 2 of our series on Seed Saving: How to Save Cucumber and Melon Seeds!

Cucumbers and Melons are part of the Cucurbitaceae family, which also includes pumpkins, winter squash, gourds, summer squash and zucchini, but in this article I will be just talking about cucumbers, melons and watermelons.

If you would like to learn about saving seeds from summer and winter squash, check out part 1 of this series:

Seed Saving: How to Save Squash Seeds

Like squash, cucumbers and melons have male and female flowers, and are normally pollinated by insects. They can cross with other varieties within 1/2 mile. If you want to be sure your variety remains pure, I will be explaining how to hand pollinate farther down in this article.

All cucumbers, except for gherkins and Armenian cucumbers, will cross with each other. Cucumbers will not cross with melons, watermelons or squash.
All common types of melons, including cantaloupe, muskmelon and vine peach, will cross with each other, and with Armenian cucumber. They will not cross with watermelons, cucumbers or squash.
All watermelons will cross with each other. They will not cross with other types of melons, cucumbers or squash.

How to Hand-Pollinate Cucumbers, Melons and Watermelon

A male flower grows on a straight stem and has an anther in the center of the flower, which is covered in yellow pollen, while a female flower has a tiny fruit attached before it even opens. These flowers have already opened and probably been contaminated with other pollen by bees, so should not be used for hand pollination.

To hand-pollinate, male and female flowers that have not opened yet are selected in the evening and taped shut with a piece of masking tape. Ideally, male and female flowers from two different plants should be selected to protect genetic diversity and prevent inbreeding, and you should always save seed from your best plants!

In the morning, remove the tape. Pick the male flower and remove its petals, then use it like a paintbrush to dust the pollen into the center of the female flower (called the stigma). You can also use an actual paintbrush to pick up pollen from the male and transfer it to the female flower.

After hand pollination, the female flower should be taped back shut or covered to prevent bees from contaminating it with pollen from other varieties. Tie a string or twisty tie around the stem so you’ll remember to save that fruit for seed, or scratch a mark onto it with your fingernail like this zucchini…

Let the fruit grow until it is completely mature – cucumbers will get large, yellow and develop a hard rind like a winter squash. Cucumbers should be left on the vine as long as possible, and once picked I like to store them for another 2-3 weeks, just to make sure the seeds are fully ripe. Melons and watermelons should be completely ripe, and the seeds will have a higher viability (a higher percentage will actually sprout and grow when planted) if they are a little overripe.

Once the fruit is done, melon and watermelon seeds simply need to be washed, dried and stored for next year.

Cucumber seeds take a little more effort. The seeds are enclosed in a slippery jelly like sack to keep them from sprouting inside the moist fruit. To remove this sack, place the seeds in a dish and cover with water. Let soak until the mixture is bubbly: 1-4 days. It may develop a little mold on top, which is fine. After it gets bubbly, rinse the seeds and dry thoroughly before storage.