How to Grow Japanese Cucumbers

Regular fertilizer, water and the right support system are key elements in growing Japanese cucumbers (Cucumis sativus) successfully at home. The thin-skinned, delicate 18-inch-long, 1 1/2 inch diameter cucumbers mature for harvest 48 to 60 days after planting. The mild-tasting cucumbers work well for slicing, salads and snacking right out of the garden. Japanese cucumbers and cultivars are annuals.

Try the heirloom Japanese cucumber variety 'Yamato Sanjaku' (Cucumis sativus 'Yamato Sanjaku'). Two other Japanese varieties to look for are 'Tasty Jade' (Cucumis sativus 'Tasty Jade') and 'Suyo Long' (Cucumis sativus 'Suyo Long').

Grow Japanese cucumbers in a garden bed in full sun -- six or more hours per day -- with deep, loamy soil that drains well.

Before planting Japanese cucumbers, spread seasoned compost 1 inch deep over the garden bed, then work it into the top 6 to 8 inches of the soil. Adding amendments and turning the soil helps create a loose, nutrient-rich growing environment.

Grow Japanese cucumbers on a trellis. Cucumber plants are by nature trailing vines that will spread laterally over the soil. The trellis keeps vines off the ground, encouraging cucumbers to grow long and straight.

Types of trellises for cucumbers include round wire cages, wire A-frames and vertical trellises.

Round cage-type trellises should be 12 to 18 inches in diameter and 4 to 5 feet tall. Plant two to three cucumber plants spaced evenly around the outside of the cage. 

An A-frame trellis with two 4- to-5-foot-tall wire panels that attach at the top work well for Japanese cucumbers. Plant the cucumbers 12 inches apart along the outside panels. As the vines mature, the cucumbers will attach to the wire, growing up and over the structure. 

Vertilce trellises should be 8 feet tall. Plan to space Japanese cucumbers 12 inches apart along the base. The length of the trellis depends on how many plants you want to grow. 

As the vines grow, they develop tendrils along the stem. These tendrils will attach to the cage or trellis. To help the vines get going on the trellis, stick the ends through the trellis. Redirect vine tips that grow outward back into the trellis by gently poking the tips through the holes. As cucumbers gain a hold on the trellis, they generally climb successfully with little or no help.

If you choose not to trellis Japanese cucumbers and instead allow the vines to trail along the ground, space the plants 48 to 60 inches apart to make room for the developing vines.

Supply Japanese cucumbers with 1 inch of water per week. Use a soaker hose to deliver water slowly to the root zone. If you prefer to use a hand-held watering device, such as a hose, set it on a soaker setting and allow the water to seep into the soil. Concentrate water around the roots.

Avoid sprinklers and other overhead watering methods. When the leaves get and stay wet frequently, Japanese cucumbers can develop diseases.

One inch of water is enough to dampen the soil 12 inches deep in a loamy garden bed.

Fertilize twice a month through the growing season with a liquid general-purpose plant food. Dilute 4 teaspoons of the liquid fertilizer concentrate with 2 gallons of clean water in a watering can. Sprinkle the diluted fertilizer over the cucumber bed around each plant. This is enough to cover 20 square feet of bedor a 5-by-4-square-foot area. Water after fertilizing.