Cucumber

Cucumber (Cucumis sativus) is an annual vine in the gourd family, native to the region from the Himalayas to northern Thailand. It’s a warm-season crop that grows best at 75–85 °F (24–29 °C), and even a light frost can kill it. The plants climb with tendrils or scramble along the ground. Trained up a support, they take very little ground space, which makes them a good fit for small gardens and patio pots.

There are two main types: slicing cucumbers, long and slender for eating fresh, and pickling cucumbers, shorter and blockier with bumpy skin. Most varieties have separate male and female flowers and need insects to pollinate them, while parthenocarpic varieties set fruit, usually seedless, without pollination. Gardening experts separate indoor varieties, grown in greenhouses or polytunnels, from outdoor “ridge” varieties.

Sow outdoors once the soil is warm. Wait until the danger of frost has passed and the soil has warmed to about 70 °F (21 °C); seeds won’t germinate in soil below 50 °F (10 °C). Sources differ a little on depth: gardening experts sow ½–¾ inch (1–2 cm) deep, gardening experts ½ inch (about 1 cm), and gardening experts and gardening experts 1 inch (2.5 cm) when sowing several seeds in a hill.

Or start indoors for an earlier crop. Sow 2 to 3 weeks before you plan to plant out, one seed per 4-inch (10 cm) pot, kept at about 70 °F (21 °C); seedlings appear in a week or two. Cucumbers don’t like their roots disturbed, so transplant gently or use plantable pots such as peat pots. Harden seedlings off and plant them out once temperatures stay above 53 °F (12 °C).

Sun, soil and spacing. Cucumbers do best in full sun and fertile, well-drained soil with plenty of organic matter and a pH of 6.0–6.8. Space plants about 1 foot (30 cm) apart.

Grow up, not out. Training the vines on a trellis or fence saves space, keeps the fruit clean, reduces disease and makes picking easier. Put supports in at planting time so the tendrils have something to grab. If you can’t trellis, bush varieties produce well in a small space.

Pots. Choose a container at least 1 foot (30 cm) wide and deep for one plant, or put two plants in a standard grow bag, and add a support.

Water often and evenly. Cucumbers have high water needs and want consistent moisture, but they also need good drainage. Even moisture matters most while fruit is setting and growing; water enough to wet the soil at least 6 inches (15 cm) down. Pots may need watering every day in hot weather. Water at the base of the plant, ideally in the morning, and keep the leaves dry to help prevent disease. A mulch keeps moisture in and weeds down.

Feed moderately. Too much nitrogen gives lots of vine and less fruit. In pots, feed every 10–14 days with a general liquid fertilizer, then switch to a high-potash feed such as tomato feed once flowering starts.

Flowers and pinching. Most greenhouse varieties are all-female and must not be pollinated, or the fruit may turn bitter, so remove any male flowers. Outdoor varieties need their male flowers for pollination. On outdoor plants, pinch out the growing tip once they have seven leaves to encourage side shoots.

Pests. Cucumber beetles, aphids, mites, whiteflies, pickleworms and squash vine borers all feed on cucumbers. The striped cucumber beetle also spreads bacterial wilt; covering young plants with row cover keeps beetles off, but remove it once flowering starts so bees can pollinate. Under glass, red spider mites are common when the air is dry, and slugs and snails go after seedlings.

Diseases. Watch for powdery and downy mildew, anthracnose, gummy stem blight, bacterial wilt and mosaic viruses. Mildew-resistant varieties are available; cucumber mosaic virus is more serious, and affected plants should be destroyed. Rotating crops and choosing resistant varieties help.

Misshapen or bitter fruit. Misshapen fruit usually means poor pollination or low fertility, and the first 10 to 20 flowers are male and won’t make fruit anyway. If bees are scarce, hand-pollinate in the morning by rubbing pollen from a male flower onto the female flowers. Bitterness comes from stress such as hot, dry weather, big temperature swings or poor nutrition.

Depending on the variety, cucumbers are ready to harvest in about 50 to 70 days. Pick pickling types at 2–6 inches (5–15 cm) long and slicing types at 6–10 inches (15–25 cm); fruits that have turned yellow are overripe and tough.

Check plants every day or two once they start fruiting. The fruit grows fast, and overgrown cucumbers left on the vine hold back new fruit, while regular picking keeps the vines producing. Cut the stem with a sharp knife or pruners instead of pulling.

Keep cucumbers in the refrigerator, where they last about a week. Gardening experts give 45–50 °F (7–10 °C) and 95% humidity as ideal, while gardening experts and gardening experts give 50–55 °F (10–13 °C) with high humidity, for up to about two weeks. Storing cucumbers near other ripening vegetables can make them bitter.

Pet poison experts list cucumber as non-toxic to dogs, cats and horses.