If you have a protected city garden or live in a mild area, olives can be grown outdoors as long as you give them a sunny position and plant them in well-drained soil, for example, against a warm wall would be ideal. IN cold or northern regions winter protection in a conservatory for example, will be required.
Once established they are extremely drought-tolerant, but plants will do better if watered regularly in dry spells during the growing seasons. To encourage strong growth, it’s a good idea to feed each spring with a general fertiliser, such as Vitax Q4.
Olives naturally shed their older leaves in spring (April in the UK) as new growth begins.
Olives are not entirely hardy in the UK, and will be damaged by temperatures below -10°C (14°F). So, in colder areas of the country, you can grow olives in large (60cm, 24ins) diameter and depth) containers. Plant in a well-drained mix of compost, such as loam-based John Innes No 3 with 20 percent by volume added horticultural grit. You can place containers outdoors in summer and then move into a cold conservatory, porch or greenhouse over winter.
Although they can cope with dry periods, olives in containers need regular watering and feeding to produce fruit. During the growing season keep the compost moist and feed with a balanced liquid fertiliser such as Phostrogen, every month. In winter, you can reduce watering, but don’t let the compost dry out completely.