When to plant Cucumbers in Cardiff

Sow seeds on their edge to a depth of 1.5 cm in modules or small pots from 1st April - 8th 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 15th April - 29th April. 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 6th May - 13th 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 13th May - 27th May 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 6th 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 20th June - 28th 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.