When you first receive your plants, check the compost is moist and plant up into 10cm pots using a good quality potting compost at a temperature of 16-18°C (60-65°F). Once the roots fill the pot, transfer the plants into 30cm (12") containers.
The grafted Cucumber plants should be trained up towards the roof with laterals (side shoots) tied to horizontal wires or strings. The tips of the laterals are usually pinched out after two leaves from the main stem provided both axils of the leaves are showing fruit buds. All male flowers should be removed and also any fruits which are being produced on the main stem itself.
It is important to ensure that the plants don't receive a check to their growth (e.g. temperature drop, incorrect watering, lack of nutrients, etc). Any such checks can affect development.
Over-cropping must be avoided and it is sometimes necessary to thin out the fruits in the early stages. Periodical top dressing with a compost such as John Innes No.1 around the base of the plant is necessary, especially if young roots are showing. A constant supply of water at the roots is essential and the atmosphere should be kept reasonably moist by overhead spraying. When the first fruits start to swell, start feeding at fortnightly intervals with a Tomato Food