Greenhouse Cucumbers - Key Growing Information
CULTURE:
Cucumbers do very well in tunnels and greenhouses, where you have more control over fruit quality and can stretch the harvest at both ends of the season. Culture is much like field cucumbers, except transplants are usually started earlier and may need extra light and heat to stay sturdy. Parthenocarpic varieties are the best choice under cover, since pollination is difficult in an enclosed space; kept apart from seeded varieties, they produce seedless fruit.DAYS TO MATURITY: Counted from direct sowing; take off about 10 days for transplants.TRANSPLANTING INDOORS:
Start seed indoors 3–4 weeks before transplanting, 1–2 seeds per cell in 50-cell plug trays. Hold them at 80–85°F (27–29°C) until emergence, using a heat mat for steady warmth, then keep days at 73–76°F (23–24°C) and nights no lower than 70°F (21°C). Transplant at about 3 true leaves, before seedlings stretch. Two rows per bed with plants 12–18" apart is typical, though spacing varies with variety, climate, disease pressure and pruning style. Disturb roots as little as possible. Plants are healthiest with root-zone soil at about 65–70°F (18–21°C); grafted plants usually tolerate cooler soil. For the first week after planting, keep both day and night near 75°F (24°C) to push fast leaf and root growth. Once fruit sets, drop nights to around 65°F (18°C) and watch the crop closely to keep it producing all season.Trellising & Pruning: Clip each plant to its own vertical string about 1" below every third leaf. Remove side shoots at each node, taking care not to damage developing fruit. Keep strings snug and reuse the lower clips, keeping at least 3–4 on each string. A lower-and-lean or lower-and-coil system suits long seasons, a sturdy structure and enough labor; the umbrella system fits a very short season or limited labor. On grafted plants, remove any roots growing from the scion and any suckers from the rootstock.
