English Cucumber

Cucumber, Cucumis sativus, is an annual vine that climbs by tendrils or spreads along the ground and is grown for its crisp green fruit. English cucumbers are the thin-skinned, long type that falls in the slicing group. Some cultivars are bred to be seedless, and newer hybrid types can set fruit without pollinating insects.

Sow seed directly in the garden after the last frost, once the soil has warmed. Wait until the soil reaches 70 °F (21 °C) because seeds will not germinate in soil below 50 °F (10 °C). Plant the seed 1 inch (2.5 cm) deep, although one seed company suggests a shallower ½ inch (1.3 cm). Seeds usually come up in 5 to 10 days when the temperature is between 65 and 85 °F (18 to 29 °C).

You can also start seed indoors 2 to 3 weeks before planting outdoors, or 3 to 4 weeks before transplanting, keeping the air above 70 °F (21 °C) by day and 60 °F (16 °C) at night. Be careful not to damage the taproot when transplanting. After thinning, space plants 9 to 12 inches (23 to 30 cm) apart, thinning them when they are 4 to 5 inches (10 to 13 cm) tall. Vines can spread 3 to 8 feet (91 to 244 cm) wide, so a trellis helps; it lifts the vines and fruit off the soil, keeps the fruit clean and makes harvest easier.

Watering. Cucumbers need high and steady moisture. Water at the base of the plant in the morning, wet the soil to at least 6 inches (15 cm) deep, and avoid wetting the leaves.

Feeding. Cucumbers need a moderate amount of fertilizer, and too much nitrogen encourages extra vine growth at the expense of fruit.

Containers. Cucumbers can be grown in a container at least 1 gallon (3.8 L) in volume and 8 inches (20 cm) deep.

Misshapen fruit and poor set. Misshapen fruit is usually caused by poor pollination or low fertility. The first 10 to 20 flowers on a plant are usually male and will not make fruit, so hand pollination can help when pollinators are scarce.

Bitter fruit. Temperature swings of more than 20 °F (11 °C), or storing cucumbers near ripening vegetables, can make fruit bitter. Water stress also causes bitterness.

Pests and diseases. Cucumber beetles, aphids, mites, whiteflies and squash vine borers feed on cucumbers, and the plant may be susceptible to glasshouse whitefly. Powdery mildew, downy mildew, bacterial wilt and mosaic viruses are common in home gardens. Keep the leaves dry when watering to help prevent fungal disease.

Pick cucumbers when they are about 2 inches (5 cm) long or larger, before the flesh turns bitter, the seeds harden or the skins yellow. Slicing types are often picked at 6 to 10 inches (15 to 25 cm), or at 5 to 8 inches (13 to 20 cm) depending on the variety. Cut the stem with a sharp knife or clippers, and pick every 2 to 3 days to keep the vines producing. Cucumbers are ready about 50 to 70 days after planting, depending on the cultivar, or 50 to 65 days from seed in another home-garden guide.

Cucumbers keep for about a week in the refrigerator. The ideal conditions are 45 to 50 °F (7 to 10 °C) with about 95% humidity. Some guides say they keep 10 to 14 days at 55 °F (13 °C). Store them away from apples and tomatoes, which release ethylene that makes cucumbers discolor.

Cucumber is listed as non-toxic to dogs and cats. One reference warns that bitter fruit can be toxic to pets, so don’t give pets bitter cucumbers. For people, wash the outside of cucumbers well under clean running water with a vegetable brush before peeling or slicing, because bacteria on the skin can move inside. Cucumbers were linked to several multi-state Salmonella outbreaks in 2013, 2014 and 2015.