When to plant Cucumbers in the UK

Sow seeds on their edge to a depth of 1.5 cm in modules or small pots from mid-April. Use a heated propagator or warm windowsill at 21–24 °C for reliable germination. Do not sow earlier than this window, as seedlings grow quickly and suffer if root-bound.

Once seedlings have two true leaves, pot them on into larger pots from late April to early May. Handle carefully to avoid damaging the delicate roots, and use a rich potting compost. Keep them in a warm, bright spot to encourage strong growth.

Plant out into greenhouse beds or large containers from mid-May to late May. Space plants 45 cm apart and plant on a slight mound to keep the stem base dry. Provide vertical support like canes or strings for the vines to climb.

Train the main stem up its support around late May to early June and pinch out the tip when it reaches the roof. Check the seed packet before removing flowers. On all-female greenhouse varieties, remove any male flowers, which have no tiny fruit behind them. Leave them on mixed-flowering varieties.

Keep the soil evenly moist from mid-May, watering at the base and away from the main stem. Once flowering starts, feed container plants every 14 days with a high-potassium liquid fertiliser.

Harvest fruits frequently while they are small and firm from early July to late October. Use a sharp knife to cut them from the vine, picking every few days to encourage more production. Regular harvesting prevents fruits becoming oversized and bitter.