Cucumber (Cucumis sativus) is a warm-weather crop and can be grown year-round in Hawaii. It grows best when the temperature is 70 degrees or higher. Plant growth slows when the temperature is below 60 degrees or above 90 degrees.
Most cucumber plants grow as vines or bush-type plants. Plants can be “monoecious,” meaning one plant produces both male and female flowers. “Gynoecious” plants have only female flowers and usually produce many more flowers than do monoecious plants. “Parthenocarpic” plants have flowers that do not require pollination and result in seedless cucumbers when left unpollinated.
Cucumber fruits are usually elongated, ranging from the 2-inch-by-4-inch pickling type, to the 2.5-by-8-inch Western type and 1.5-by-18-inch-long oriental type. Depending on the type, cucumbers are good for slicing for fresh use and pickling, with some varieties being suitable for both fresh and pickled consumption.
Hybrid cucumbers such as Lani, Milo and Burpee varieties can be grown in Hawaii. Oriental varieties are also found locally. Bush varieties can be grown in small spaces or as container plants in 3- to 5-gallon containers.
Cucumbers can be grown in well-drained, moderately acidic to neutral soil (pH 6 to 6.8 is optimum) with a good level of soil organic matter. Cucumber seeds can be planted directly in the soil, 3 or 4 seeds per hole, ½- to ¾-inch deep.
Once plants sprout, thin them out to one or two plants per hole spaced 15 to 18 inches apart in rows spaced 4 to 5 feet apart. Vines grown on sturdy trellises 5 to 7 feet tall reduce the damage to cucumber fruits from soil rot and make pest control easier. Seeds can also be planted in pots and transplanted later, but take care not to damage the roots.
Weed whenever necessary while cucumber plants are small. Weeding will become more difficult when the plants start to vine. Water needs are largely dependant upon soil type and weather conditions. In general, lighter soils require more frequent irrigation than heavier soils. If a pot is used, water daily after the plant begins to fruit.
Most cucumber varieties will produce fruit ready for harvest in 50 to 60 days. Cut the stem near the fruit and avoid pulling the fruit. Frequency of fruit will vary by plant, location and time of year. Removing fruits as they mature will aid in maintaining plant vigor and productive capacity.
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Information in this column came from Richard Ebesu’s update to a University of Hawaii College of Tropical Agriculture and Human Resources extension publication by Dr. Ken Takeda and Richard Sakuoka. Ebesu is an extension agent with the Kauai Extension Service.