Cucumber

Cucumber is a warm-season annual creeping vine in the family Cucurbitaceae, producing cylindrical to spherical fruits eaten as vegetables. Varieties span slicing, pickling, and seedless types, ranging from compact outdoor plants to vigorous greenhouse climbers reaching 2–3 m. Plants demand warmth at every stage — from germination through fruit set — and will not tolerate frost. Excellent disease-resistant open-pollinated varieties thrive in Nordic outdoor conditions given adequate heat and a sheltered plot.

Growing

Start seeds indoors 4–5 weeks before transplanting. Sow 1–2 cm deep in pots, placing 3–4 seeds per pot; maintain a germination temperature of 22–26 °C for reliable sprouting in 5–7 days. Thin to 1–2 plants per pot and grow on in a bright, well-ventilated spot. Harden off gradually before transplanting. Move plants outdoors only once the soil is thoroughly warm and all frost risk has passed — soil temperature should be at least 12 °C and nights reliably above 10 °C. Space plants 25–35 cm apart in rows 100–150 cm apart. In warm, sheltered positions, direct sowing outdoors at 1–2 cm depth is possible; covering the soil with fleece one to two weeks beforehand raises the temperature several degrees and speeds germination.

Care

Keep soil consistently moist but never waterlogged; cucumbers are shallow-rooted and stress quickly under drought, which promotes bitterness. Apply a balanced liquid feed every 10–14 days once vines begin to run, switching to a potassium-rich feed when flowers appear. Train climbing varieties up a trellis or wire support — vertical growing improves air circulation, reduces disease pressure, and produces straighter fruit. Pinch out the growing tip after 5–6 leaves on greenhouse types to encourage lateral branching. In cooler conditions, use row cover or cloches to maintain warmth around young plants.

Harvest

Begin checking plants daily once fruits reach the expected size for the variety — typically 7–25 cm depending on type. Harvest slicing cucumbers when dark green and firm; pickling types are best taken young and crisp before seeds enlarge. Overripe fruits turn yellow, signal the plant to slow production, and become seedy and bitter. Cut fruits cleanly with scissors or a knife rather than pulling. Frequent harvesting — every 1–2 days at peak production — is the single most effective way to extend the harvest window and maximise total yield.

In the kitchen

Slice fresh into salads or onto open sandwiches. Cut into spears for dipping. Use in cold soups such as gazpacho or tzatziki. Pickle whole small cucumbers or slices in brine or vinegar with dill and garlic. Japanese types are excellent eaten young with sushi or lightly dressed. Crystal Lemon and Boothby's Blonde varieties are sweet enough to eat straight from the vine like fruit.

Storing

Freshly picked cucumbers keep for up to 1 week in the refrigerator at 10–13 °C — temperatures below 10 °C cause chilling injury and pitting. Do not store near ethylene-producing fruits such as tomatoes or apples. For longer preservation, pickle in brine or vinegar and process in sterilised jars; pickled cucumbers keep for up to 12 months in a cool, dark place. Fermented cucumber pickles keep refrigerated for several months.