Compost and potting conditions
Olives are best grown in well-drained pots in a loam-based compost. Good drainage is paramount. Growing an olive tree in a pot has the advantage that it can be protected from very cold weather as you can take it into a conservatory or glasshouse. You can also wrap it up in horticultural fleece or a frost protecting sheet.
It is a slow growing plant, so will only need re-potting every two to three years.
If you wish to plant the tree in soil, low to medium fertility is preferable. Planting in fertile soils may result in the growth of too many shoots and leaves and very little fruit.
Olive trees will tolerate acidic or alkaline soils. Avoid areas that may become waterlogged in the wetter months.
Light and temperature
The sunnier the position the better. A south or west-facing location with protection from north winds is preferable.
In areas where the minimum temperature is -2°C, no extra protection is needed. Olive trees will even tolerate -7°C for short periods. The bigger and older the tree the lower the temperature it can withstand.
Watering and feeding
Water is needed during the summer months. Feed from March until October with a medium to high nitrogen feed.
Use Olive Focus, which is a liquid fertiliser formulated specifically for olive trees. Use 10ml per litre of water.
It's easy to prune olive trees. Regular pruning will keep the shape and size of the tree as you require it. Prune lightly in mid-spring to early summer. Never prune in winter. Like many Mediterranean trees, olives need time and heat to heal wounds.
Flowering and fruiting
Olive trees produce small cream coloured flowers. To flower and fruit, they need two winter months of temperatures below 10°C, which is something known as chilling requirement. Most cultivars are self-pollinated by insects or the wind.
Pests and diseases
In the UK, olive trees may be affected by various scale insects, whiteflies or thrips and red spider mites. An ideal way to kill any of these insects is regular spraying with SB Plant invigorator, a contact insecticide that can be used even during the harvest period. Less commonly, olive trees may be affected by root-knot nematodes or verticillium wilt.