Cucumbers transplant badly so if you are not sowing them directly outside make sure you sow them in situ or small pots or modules after all risk of frost has passed. If you are sowing them directly outside you should prepare holes of 30 cm wide and deep working in plenty of well-rotted compost or manure as you backfill and cover with 15 cm of manured soil made into a small mound to ensure sharp drainage. Place the seeds 2 cm deep and 2-3 seeds per site or pot. Seeds germinate at minimum 20 Celsius degrees (68 F) and seeds sown in pots need a minimum temperature at night of 16 Celsius degrees (61 F) for about 4 weeks after sowing until the seedlings are planted out. Protect plants with cloches or fleecy film after planting if you live in a cool climate zone.
Grow trailing varieties up on supporting fences, nets or canes or allow them to twine up strings, placing them 45 cm apart if climbing or 75 cm apart if you let them trail over the ground. Feed the cucumbers every two weeks with a high-potash fertilizer or organic liquid feed. Water them regularly, specially after transplanting and also during the growing, flowering and fruiting periods because cucumbers have a shallow root system and can suffer when no watering is provided during drought periods. Mulching is also helping to provide uniform moisture, conserve water and reduce weeds.
When the plant have 5-6 leaves, nip out the growing point them train the resulting shoots. When those soots reach the top of the support nip them out two leaves beyond a flower so laterals will develop and they will carry more fruits. Harvest the fruits regularly after 12 weeks after sowing when they have 15-20 cm long. If you grow gherkins also, those need to be picked when they have only 2.5-7 cm long or when they have reached pickling size.