We are often asked how to grow olives in the UK. The UK climate is surprisingly well suited to Growing Olives. Despite being a Mediterranean plant, an olive tree needs at least two months cold weather to produce flower and fruit. Temperatures below 10 degrees Celsius, along with a fluctuation in night and daytime temperatures initiates the fruiting process.
Picking the Right Olive Tree
Depending on the variety of olive tree you have, there is no reason why you cannot successfully harvest olives from your olive tree. Make sure you choose a variety that produces fruit. Olive trees grown from seed generally do not fruit, and if they do are unlikely to have the same characteristics as the parent plant. Buying from a reputable source will ensure you get a suitable olive tree. All the olive trees at Olive Grove Oundle are sourced from specialist, recognised growers in Spain.
Feeding your Olive Tree
To promote flowering and growing olives, as well as general tree growth, top dress with a general high nitrogen fertiliser (ideally slow-release) in early Spring. This should be applied around the base of the tree. Continue to feed every few weeks throughout the growing season with either Vitax Q4 or seaweed extract. You should stop feeding in late July as this will encourage new growth which is susceptible to Winter damage. As with most container grown plants, olive trees grown in pots will require more feed than those grown in open ground but beware of overfeeding which can cause excessive green growth.
Pollination and Flowering
Olive trees are pollinated by wind so they will need to be outdoors when flowering. Whitish blooms are produced in loose clusters in late Spring and by shaking the branches gently at this time you will help to distribute the pollen. Although most olive tree varieties are self-fertile, in our cooler climate it may be useful to introduce another cultivar cross-pollinator to boost pollination. This should help increase fruit production.
Hot and dry winds or prolonged cool, wet weather during flowering time will have an impact when growing olives. Consequently, as with other fruit trees, yields will vary from year to year. Olive trees flower and fruit on one year old wood and fruit will not be produced on any shaded areas of the tree.
Correct pruning is therefore necessary in order maintain fruit production. They key is getting the right balance between density and sunlight. We recommend taking a look at our guide on olive tree pruning if you need some more information.
Remember to water your olive tree. Flowering can be inhibited by very dry soil conditions. Watering between February and May if the weather is dry is imperative if you are aiming to grow your own olives. Continue to water throughout the summer to swell the fruit and prevent it from shrivelling. You should never allow olive trees to sit in water. Ensure there is adequate drainage and water in small amounts, frequently.
Thinning the crop
Thinning the fruit may be necessary if a heavy crop of olives is produced. Reducing the number of fruit to 3 – 4 per 30 centimetres of branch within a few weeks of flowering will prevent fruit drop and encourage ripening.
By following these few simple rules it is possible to produce quite substantial yields from your olive tree within three to five years of planting.