Keep Exploring!
When you make a purchase from Seed Savers Exchange, you help fulfill our nonprofit mission to protect our food and garden heritage. Do even more good by making a donation to help us preserve and share even more heirloom varieties!
Growing Guide: Cucumber
Grow and Save Cucumber Seeds
Cucumbers (Cucumis sativus, fam. Cucurbitaceae)Â grow well in many regions of the United States, producing prolific quantities of fruit that can be enjoyed fresh or preserved as pickles. Cucumbers are a great plant for beginning seed savers.
Slicing vs Pickling Cucumbers
Cucumbers are commonly categorized into two broad market classes: slicing and pickling. You can slice or pickle any cucumber, however certain varieties are better suited for one or the other.
Slicing Cucumbers
Slicing varieties are best suited for fresh eating and generally have green skin with white spines.
Favorite slicing varieties:
Pickling Cucumbers
Pickling varieties are commonly dark green and sometimes have prominent warts. Pickling cucumbers are suitable for fresh eating and pickling.
Favorite pickling varieties:
How to Grow Cucumbers
Time of Planting
Direct-sow (preferred): Direct-sow cucumber seeds after the danger of frost has passed and the soil temperature has warmed.
Cucumber transplants: Cucumbers are prone to transplant shock and prefer to be sown directly into the soil, however you may also choose to start cucumber seeds indoors. Start cucumber seeds indoors no earlier than 4 weeks before your last frost date. Starting cucumber transplants earlier than this will cause greater root disturbance.
To help mitigate root disturbance, try starting cucumber seeds in soil blocks or biodegradable pots that can be planted directly into the soil. Transplant cucumbers after the danger of frost has passed and soil temperature has warmed.
Light Requirements
Full sun, at least 6-8 hours daily.
Spacing Requirements
You can grow cucumbers either on a trellis or on the ground. The spacing for growing cucumbers for seed is the same as when growing cucumbers for eating.
Trellis (recommended):Â We recommend trellising cucumbers. If direct-sowing, plant seeds 1 inch deep, 12-15 inches apart. If transplanting, space cucumber plants 12-15 inches apart.
Without a trellis: Cucumbers can also grow on the ground without a trellis (bush habitat). In your garden, make 12-inch hills at least 6 feet apart. Plant 6-8 cucumber seeds per hill, 1 inch deep. After germination, thin to 3-4 plants per hill.
Time to Germination
4-10 days
Trellising
While not required, trellising cucumbers has many benefits:
- Improves airflow and keeps fruit off the ground, mitigating disease
- Makes identifying pests and other potential problems easier
- Makes harvesting easier
- Saves space in the garden
Learn how to build several types of trellises
Growing Cucumbers in Containers
Cucumbers can grow in containers, though they prefer the ground. Make sure your container is deep, opaque, and has drainage holes. Use high quality potting soil fortified with a healthy amount of compost to add nutrients, improve drainage, and help retain moisture. Smaller varieties, such as ‘Miniature White,’ are ideal for container growing.
Learn more about container gardening
Plant Care
Cucumbers benefit from steady moisture. Water consistently to prevent blossom end rot and bitter tasting fruit. Water deeply at the base of the plant and keep the leaves dry to help prevent disease. Keep the soil moist, but do not overwater—this can cause the roots to rot.
Weed consistently to ensure the plants have room and resources to grow without the competition of weeds. Hand hoes, collinear hoes, and small scuffle hoes are handy for precision weeding. Be sure to scratch every square inch of soil, even if you don’t see a weed, in order to catch any germinating “thread stage” weeds.
Common Garden Pests
Cucumbers are particularly susceptible to cucumber beetles, slugs, deer, raccoons, and squash vine borer. Pests such as cucumber beetles and slugs can be picked off and placed in buckets of soapy water. Use fencing to protect plants from deer and raccoons.
Common Diseases
Cucumbers are susceptible to a number of diseases, many of which can be mitigated or prevented by trellising plants. Trellising helps improve airflow around plants, thus reducing bacterial and fungal infections.
Anthracnose:Â In cucumbers, anthracnose causes large brown leaf spots, tan lesions on stems, and black spots on fruit. This disease is caused by a fungus, thrives in wet conditions, and can spread through soil and seeds. To prevent anthracnose, buy seeds from a reputable source, water at the base of plants, and practice crop rotation.
Bacterial wilt: Bacterial wilt causes wilting among cucumber leaves, which will cause the entire plant to rapidly deteriorate and die. This disease is often spread by cucumber beetles and can be prevented by pest management. Remove infected plants from the garden and dispose in the trash.
Belly rot:Â Belly rot appears as a dark, sunken lesions on an area of a cucumber that is touches the soil and is caused by a fungus. To prevent this, trellis cucumber plants to keep the fruit off the ground or use mulch to create a barrier between the fruit and the soil.
Blossom end rot: Similar in appearance to belly rot, blossom end rot occurs on the end of the fruit where the flower used to be (the end not attached to the vine). Blossom end rot is caused by a calcium deficiency, usually from inconsistent watering. To prevent this, keep the soil consistently moist.
Downy mildew: Downy mildew in cucumbers appears as yellow and brown spots on leaves with a dark gray fuzz on the undersides of leaves. A type of mold, downy mildew thrives in damp conditions can quickly destroy a cucumber crop. To prevent downy mildew, trellis plants to maintain airflow, water at the base of plants and keep the leaves dry, and sanitize garden tools. Remove infected plants immediately and dispose in the trash.
Powdery mildew:Â Powdery mildew in cucumbers appears as white blotches on leaves and affects fruit production. This fungal issue can be prevented by providing adequate airflow between plants. Make sure cucumber plants aren’t spaced too close together and use a trellis to improve airflow. Keep your cucumber plants weeded to avoid overcrowding.
Tip: For more information on common pests and diseases, contact your local extension office.
When and How to Harvest for Food Consumption
Harvest cucumbers once the fruit reaches the size you prefer. You can pick cucumbers early for making pickles or you can let them grow a little longer for larger slicing cucumbers. Harvest cucumbers frequently as the fruit gets large quickly.
Use pruners or a knife to cut the vine about one inch from the fruit. Leaving some stem on harvested cucumbers helps prevent rotting in storage. Make sure not to damage any flowers that may be on the plant.
Once plants begin producing fruit, check your garden daily for ripe cucumbers. Consistent harvesting will encourage plants to produce more fruit. One cucumber plant can produce anywhere from 10 to 20 cucumbers.
Eating
Cucumbers add a great crunch to fresh green salads, yogurt sauces, and sandwiches. You may also want to try pickling your garden cucumbers or this White Gazpacho (Ajo Blanco) recipe from Beth Dooley, chef and author. Cucumbers add a fresh, vibrant flavor, and sherry vinegar makes a snappy finish. It’s hearty enough for lunch or a light dinner paired with tomato-topped bruschetta.
Storing
Store cucumbers unwashed in the humid crisper drawer of the refrigerator. Cucumbers will keep for 10-14 days at temperatures of 45-55 degrees F and a relative humidity of 85-95%.
Cucumber Brining (Video)
Ruth Hampton of Trout River Catering walks us through one of the tricks of her trade to keep watery vegetables looking delicious: cucumber brining.
Originally filmed for the Conference & Campout 2020.
How to Save Cucumber Seeds
Life Cycle
Annual
Recommended Isolation Distance
Cucumbers have separate pollen-producing (male) and pollen-receiving (female) flowers and are pollinated by insects. To produce true-to-type seeds, separate different cucumber varieties by at least 800 feet – ½ mile.
Other Isolation Methods
If achieving a distance of 800 feet between cucumber varieties isn’t possible, you can isolate varieties by other methods.
Physical Barriers: Use isolation cages, tents, or other structures to keep varieties separated. However, since cucumbers are pollinated by insects you will need to introduce your own pollinators.
Hand-Pollination
It is possible to pollinate cucumber plants by hand, similar to how you would pollinate squash, although learning to handle the smaller, more delicate cucumber blossoms requires patience and practice.
Individual cucumber flowers open in the morning and are short-lived. Hand-pollination generally should occur by midday or earlier.
To do this, first isolate the flowers by tying mesh bags around those that are about to open.
Identify which flowers are pollen-producing (male) and which are pollen-receiving (female). Pollen-receiving flowers will be attached to an ovary, which will look like a very small cucumber. Pollen-producing flowers will likely appear first and more frequently. Start hand-pollinating once pollen-receiving flowers appear.
Once the flowers open, remove the mesh bags off of the male and female flowers. Remove male/pollen-producing flowers from the vine, and remove their petals. Use the male flowers to “paint” pollen onto the center of the female/pollen-receiving flowers. Pollinate each female with multiple male flowers.
Tie a ribbon to the stem of each pollinated flower to distinguish fruits that have been pollinated by hand from those pollinated by insects.
After pollination, replace the blossom bag on the female/pollen-receiving flowers. You may remove the bag once the flower wilts to allow the fruit to grow.
Tip: hand-pollinating can help increase cucumber yields if insects are lacking in your garden.
Learn more about isolation methods
Recommended Population Sizes
You only need to plant 1 cucumber plant in order to harvest viable seeds. Cucumbers are self-compatible and rarely exhibit inbreeding depression.
To maintain a variety over time, save seeds from between 5-10 plants. If you’re saving seeds for genetic preservation of a rare variety, save seeds from 25 plants.
Assessing Seed Maturity
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.
Most varieties approach seed maturity upwards of 45-60 days after pollination.
Harvesting
If weather and plant health allow, the fruits can be left on the vine in the garden as long as possible while they continue to mature and soften. Otherwise, the fruits can be picked and held in a container until the fruits begin to soften. Mature cucumbers will pull easily from the vine when ripe.
Cleaning and Processing
Cucumbers are a wet-fruited crop, and are cleaned using wet processing methods.
Extracting Seeds
Cucumber seeds grow in a cavity inside of the fruit. In order to extract the seeds, cut cucumbers in half lengthwise. Scoop out seeds and any surrounding pulp from the seed cavity into an open container.
Fermentation
Similar to tomatoes, cucumber seeds are encased in a gelatinous coating that must be removed before rinsing the seeds. Allow the mixture of seeds and pulp to sit for 1-3 days at a temperature between 70-80 degrees F.
Decanting
When fermentation is complete, decant the seeds by adding water to the container and stirring the mixture. The pulp and lightweight, immature seeds will float to the top and can be poured off, leaving only viable seeds that will have settled at the bottom of the container.
Repeat this step as many times as needed until the water added to the container is clear.
Rinsing
After decanting the mixture, rinse the remaining seeds through a strainer or colander. Rinse any stubborn pulp or coatings from the seeds with a hose or sink sprayer.
Drying
Dry the seeds completely as soon as possible after rinsing to prevent mold or premature germination. Spread cucumber seeds in a single layer on coffee filters, baking sheets, or screens. Using fans can help seeds dry faster.
Dry the seeds in a cool, dark, dry place with adequate airflow. Make sure the seeds are out of reach from mice and other critters!
Tip: Drying seeds in between two screens (seen in the photo above) is a great way to protect seeds from rodents.
Cucumber seeds are dry when they can be easily snapped in half. Seeds that bend without cleanly snapping need more time drying.
Storage and Viability
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 5 years.
How to Save Cucumber Seeds (Video)
Follow along with this video through the steps of extracting, cleaning, and drying seeds from cucumbers grown at Heritage Farm.