How to Plant, Grow, and Save Seeds from Cucumber (Cucumis sativus)
Cucumber grows well in many regions of the United States, producing prolific quantities of fruit that can be enjoyed fresh or preserved as pickles. Cucumber is a great plant for beginning seed savers.
Direct-sow cucumber seeds after the danger of frost has passed and the soil temperature has warmed. In your garden, make 12” hills at least six feet apart. Plant 6-8 cucumber seeds per hill. Plant seeds 1” deep. Cucumber seeds will germinate in 4-10 days. After germination, thin to 3-4 plants per hill.
Once cucumber plants begin producing fruit, check your garden daily for ripe cucumbers. You can pick cucumbers early for making pickles or you can wait a while for larger slicing cucumbers.
Cucumber plants being grown for a seed harvest occupy garden space for a longer time than those grown for eating, approaching seed maturity upwards of 45-60 days after pollination, but they are otherwise cultivated in the same way for both purposes.
Cucumbers are particularly susceptible to cucumber beetles, slugs, deer, raccoons, squash vine borer, belly rot, downy mildew, anthracnose, and powdery mildew. Pests such as cucumber beetles can be picked off and placed in buckets of soapy water. Trellising can help improve airflow around plants, thus reducing bacterial and fungal infections.
Eating and Storing
Cucumbers add a great crunch to fresh green salads, yogurt sauces, and sandwiches. Cucumbers will keep for 10-14 days at temperatures of 45-55 °F and a relative humidity of 85-95%.
Cucumber is an annual crop. It will complete its full life cycle, including germination, reproduction, and death, in one growing season.
When saving seeds from cucumber, separate varieties by 800-1,600 feet. You only need to plant one cucumber plant in order to harvest viable seeds. To maintain a variety over time, save seeds from between 5-10 plants.
Cucumbers are eaten as immature fruits. When cucumbers are grown for seed, harvest is delayed until the fruits reach botanical maturity. As the seeds develop, the cucumber will continue to grow beyond its market-mature size, eventually changing color and losing firmness as the seeds reach full maturity. Cucumbers can change color to yellow or orange. It is best to wait several weeks after this color change before extracting the seeds.
Cut cucumbers in half lengthwise to extract the seeds. Scoop out seeds and any surrounding pulp from the seed cavity. Place this mixture of seeds and pulp into a small bucket or jar with some water. The mixture needs to undergo fermentation for one to three days to remove the pulp from the seeds. The fermenting mixture should be held in an open container at temperatures between 70-80 degrees. When fermentation is complete, decant the seeds by adding more water to the container and stirring the mixture - the pulp and lightweight seeds will float to the top and can be poured off, leaving only viable seeds which will have settled at the bottom of the container. Once the seeds have been rinsed clean, set the seeds out to dry on coffee filters or old window screens until they can be cleanly snapped in half.
Store cucumber seeds in a cool, dark, and dry place in an airtight container to keep out moisture and humidity. When stored under these conditions, cucumber seeds will remain viable for five years.