Squash, melons and cucumbers, while all different plants, all have the same seed-saving technique. While not difficult per se, seed saving from these plants does require some knowledge. Saving these seeds requires a good eye, and hand pollination. In order to utilize distance isolation for squash, cucumber, and melons, at least half a mile is required, making it the majority of the time not an option for home seed savers, especially when taken into account the fact that neighbours are quite likely to be growing these plants as well.
While these three plants themselves are incompatible with each other (cucumbers will not cross with squash, for example), they are highly susceptible of cross-pollinating with other varieties within their own species and genus.
The first thing is to be able to identify the differences between a male and female flowers. A male flower, at the bottom of the blossom, will flow directly into the stem. The female flower, however, will have a small bulb. This is the start of an (as yet) unpollinated female flower, and that bulb will grow into your fruit. The female flowers can only be fertilized by having the pollen of a male flower deposited into the female.
Since distance won’t work for the majority of home gardeners, what is left is using some form of barrier isolation to ensure the seed stays pure. However, since this barrier method will block out all insects from getting in, and insects (most commonly bees) are how these flowers are fertilized, that leaves us with hand pollination.
- Fruit to save seed from
- Clothes pin or bag for isolation
- Seed packets
- Paper plates/tin foil/wax paper/butcher’s paper
The first thing to do is to locate a male and a female flower, either on the same plant or from the same variety of a different plant (this is recommended if you’re growing more then one plant of the same variety as it will diversify the gene pool).
Either caging or bagging will work well to block off pollinators from getting into your blooms. A technique I like to use is to locate a male and female flower that is almost ready to open (but hasn’t yet), get a clothes pin, and simply pin them shut. It’s quick, and easy, and this way the petals of the flowers themselves work as the physical barrier. When the flowers have reached their full mature orange and are attempting to open, simply pop off the clothes pins, pick the male flower off the stem, and press it into the female flower. Once you’re done, close and pin the female flower (or rebag it) to ensure that no insects come along and possibly contaminate your hand-pollination with pollen from another plant.
Once the female flower begins to fall off (this can take place anywhere between a few days and a week), take off your bag or clothes pin and you’re done. Be sure to mark any fruit you’ve hand pollinated so you’re sure to save seeds from the right one. A dab of permanent marker on the skin, or a piece of bright yarn around the stem will serve well.
Cleaning The Seed
Be sure to let the fruit you’ve selected for seed to fully mature on the vine. If this turns out to be impossible (due to weather conditions) let the fruit mature as much as possible and then let it finish maturing in a warm, dry area. This ensures your seeds will be fully grown within the fruit, increasing your germination rate.
Squash, cucumber, and melon seeds are wet, but unlike tomato seeds, don’t need a special fermentation process in order to become ready for storage.
Take your mature fruit and cut it vertically in order to expose the whole seed cavity at once. Take a spoon and scoop out all the seeds. Place them in a sieve or colander and rinse well. You want to be sure to get off all fruit innards from your seeds to avoid having your seeds mould in storage.
Place your seeds in a warm, dry location out of direct sunlight. On a paper plate, tin foil, wax/butcher’s paper, fine mesh, or even an old baking sheet will do. Spread them out as much as possible so they aren’t touching each other. Let them dry for about a week (this may take longer or shorter depending upon your climate).
Once your seeds are fully dry, package them in paper envelopes, and store in a cool, dry place until they are ready to be used. Squash seeds will last for about 2 years in regular storage, so if you are planning to store them for any length of time greater than two years, place them either in cool or cold storage. See the article on how to create your own seed bank for more information on this.
A Note On Zucchini, Summer Squashes, and Cucumbers
It’s important to note that these plants, when harvested for eating, are immature. In order to save seeds from them it’s important to let the fruit fully mature on the vine. Since they will stop producing once the plant produces mature fruit, save letting them mature until the end of the season.