Oranges are not frost hardy so need to be grown in a greenhouse or conservatory. There are two main types, the Sweet, which is suitable for eating and the Sour, which is usually used for making marmalades. Sweet varieties include Jaffa, Parramatta, Late Valencia and Washington Navel. The best-known Sour variety is Seville. All are grown as bush trees.
Soil Conditions and Siting
Oranges hate bad drainage so they should be planted in a light sandy loam, enriched with plenty of organic matter. The pH of the soil should be between 6.0 and 6.5. The site should be sheltered and sunny.
Planting
Plants are available container grown or balled, both of which can be planted at any time of the year. They are usually grafted onto a rootstock. When transplanting ensure that the join to the rootstock is at least 4" (10cm) above the soil level.
Maintenance
Feeding
Apply a dressing of blood, fish and bone in spring and autumn. The young roots of oranges are very tender so care should be taken when applying fertilisers. They should be applied sparingly and watered in well. Apply a mulch of well-rotted compost or manure to help conserve moisture.
Ensure that the plant is kept well watered. This is particularly important in the first couple of years of growth.
Pruning
After harvesting, cut back the current season's growth to 4" (10cm). Thin out overcrowded branches.
Harvesting
Oranges are ripe when they turn bright orange. They can be left on the tree until required. They will store on the tree in this way for up to six months. Twist the fruits gently off the branches. Depending on the variety, they can be eaten raw or made into marmalade.
Pests and Diseases
Gall Wasps, Red Spider mites, Aphids, Scale insects and Lemon Scab are possible problems. (See the pests and diseases sections for prevention's and cures).
© copyright 1999, P. A. Owen