A greenhouse cucumber that doesn’t need bees. Iwa is a Polish salad cucumber variety for growing in polytunnels and greenhouses. The plants are parthenocarpic – they set fruit without pollination, so they produce a crop even in an enclosed tunnel where no insects can enter. The fruits are short (15–20 cm), cylindrical, dark green, smooth and completely free from bitterness. You can harvest the first ones just 30–50 days after planting the seedlings.

At a glance

• Type: salad cucumber, parthenocarpic, for protected cultivation
• Fruits: 15–20 cm, dark green, non-bitter
• Sowing for seedlings: mid-February – late March (spring harvest) or mid-June – mid-July (autumn harvest)
• Harvest: 30–50 days after planting the seedlings
• Position: polytunnel or greenhouse, fertile soil
• Difficulty: medium – requires protection and training
• Number of seeds per packet: approx. 35 (1 g)

What makes this variety stand out

Iwa has been one of the most popular amateur varieties for tunnels for years because it solves the most common problem of cucumbers grown under cover – lack of pollination. Parthenocarpy means fruit without seeds, uniform and free from bitterness regardless of the weather. The short, cylindrical fruits with thin skin are classic “sandwich cucumbers”: juicy, crisp and requiring no peeling.

The variety is productive and early – with good training, one plant can produce fruit for many weeks. It shows resistance to scab; it is more susceptible to powdery mildew, so good air circulation in the tunnel and watering at the base are important.

Growing step by step

Sowing (from mid-February to late March or from mid-June to mid-July, for seedlings): sow the seeds individually in 8–10 cm pots, 1–2 cm deep, at a temperature of 25–28°C. Germination occurs after 3–6 days. Grow the seedlings in bright, warm conditions (no less than 18°C at night); before planting, do not harden them at temperatures below 15°C. The second sowing period provides an autumn harvest in the tunnel.

Planting in the tunnel: plant out seedlings with 3–4 leaves 3–4 weeks after sowing, when the temperature in the tunnel does not fall below 14–15°C at night (in spring, usually from the second half of April to May). Plant at a density of 2 plants per m², approximately 100 × 50 cm apart. The soil should be fertile and rich in humus, with compost added.

Training: train the plants vertically along strings – this is essential for a good crop under cover. Remove fruitlets and side shoots from the lowest 4–5 nodes; higher up, prune side shoots after the first or second leaf. When the main shoot reaches the wire, drape it over or pinch it out.

Care: water with warm water at the base, preferably in the morning, and fertilise weekly in small doses (cucumbers are heavy feeders but do not tolerate high salinity). Ventilate the tunnel in hot weather; humidity should be high, but without condensation on the leaves. Harvest the fruits every 2–3 days, when they are 15–20 cm long.

Uses

Iwa is a cucumber for eating fresh: in sandwiches, cucumber salad, salads, tzatziki and summer chilled soups. Its thin skin and lack of seeds mean it can be sliced whole. The short fruits are also suitable for quick pickling – simply harvest them at 10–12 cm. A variety for polytunnels and greenhouses in spring and autumn, also suitable for a large pot on a sheltered terrace.

Gardener’s tip

Specifications