Choose cucumber varieties to save seed from which are least likely to need to be isolated due to open pollination; these include Armenian cukes, West Indian gherkins and serpent gourds which belong to different families and do not cross.
Grow only one variety, or separate by one half mile (805 m.) to eliminate the possibility of cross pollination. For the most optimal cucumber seed collection, select from only disease free plants which have the most flavorful fruit. Seed must be harvested when the fruit is mature, so allow the cucumber to languish on the vine past its eating stage – near the end of the growing season.
Fruit will be orange or yellow when fully ripe, and ready to pluck mature seeds from. In order to harvest seeds from fleshy fruits such as cukes or tomatoes, the wet method of removal should be applied. Remove the fruit cucumber seeds and allow them to ferment in a bucket for three days with a small amount of warm water in order to remove the gel coating surrounding the seeds. Stir this concoction daily. This fermentation process kills viruses and separates the good seeds from the pulp and the bad seeds.
The good seeds will sink to the bottom while the bad seeds and pulp float at the surface. Pour off the pulp, water, mold and bad seeds carefully after your three days have passed. Remove the good seed and spread them on a screen or on paper towels to dry thoroughly. Once completely dry, your seeds can be stored in envelopes or a glass jar with a clear label specifying the date and variety. Place the container in the freezer for two days to kill any residual pests and then store in a cool, dry place such as the refrigerator. Seed viability decreases over time, so be sure to use the seed within the next three years.
You may just need to be patient. Cucumbers, like squash, pumpkins, watermelons, cantaloupes, and many other plants, produce male and female flowers separately on the same plant. They often begin producing male flowers several weeks before the females appear. The males make pollen and are necessary, but they do not produce fruits. Look to see if there is a little cucumber behind the flower. If you see a baby cucumber, you have a female flower. If you just see a slender stem going right up to the back of the flower, you have a male flower. If your plants have female flowers and the fruits still aren’t setting, be sure that the plants are not excessively dry.
The leaves may wilt on hot days, but they should recover as the temperature drops in the evening. If they are still wilted by morning, you are not watering them enough, or you are watering too shallowly and too often. Excessive nitrogen fertilization also could be a problem. If the nutrients are unbalanced, the flowers will drop. Also, if there are no bees to pollinate your cucumber flowers, you will have to transfer pollen from the male flowers to the female flowers by hand. Use a cotton swab or soft-bristle paintbrush to transfer pollen.