Grapefruit

This page has information about growing grapefruit at home in the Northern Territory (NT).

About grapefruit

Name: citrus paradisi (rutaceae).

Origin: grapefruit is believed to have originated in Barbados as a cross between sweet orange and pummelo.

Distribution: grapefruit is mostly grown in the United States, Israel, Cuba, Mexico, Argentina and southern Africa.

Australian distribution: grapefruit grows in most mainland states and in the Darwin and Katherine areas of the NT.

Description

The grapefruit tree is evergreen and small. Tree size will depend on the environment, the type and how it's looked after.

The leaves are often large and oval in shape, glossy green in colour, dotted with oil glands and have broadly winged leaf stalks.

Flowers are white, large and fragrant. Branches sometimes have spines but these tend to be flexible, slender and blunt.

The fruit has a yellow rind and yellow flesh. 

Preferred climate and soil

Grapefruit trees prefer low or moderate rainfall with cool winters and warm to hot and dry summers. 

In the NT, fast growing and early maturing grapefruit trees are best. You may need to irrigate grapefruit during the Dry Season. 

Citrus trees like grapefruit will grow in a range of soil types. They do well in soils of a medium texture at moderate depth.

They like high fertility soils with a slightly acid pH, low salts and good drainage. 

Varieties

There are many grapefruit varieties available. They should be chosen to suit the area in which they are grown.

Pink and red-fleshed grapefruit varieties like Rio red, flame and star ruby grow well in the NT. 

White grapefruit varieties like marsh tend to be less acidic and more pleasant to eat when grown in tropical conditions. 

Propagation

Grapefruit trees grow best as grafted trees rather than seedlings. Grafted trees should be bought from accredited nurseries.

In the NT, trees need to be pruned from a young age to ensure good branch structure. Trees need to be watered in the Dry Season. 

Timing of fertilising with nitrogen is important.

Pests and diseases

There are several pests and diseases that affect this crop, including citrus leaf miner, red scale, oriental spider mite, fruit piercing moth, root rot and collar rot.

You will have to look after the crop to help reduce loss and damage. 

Fruit season

Backyard grapefruit trees may flower and fruit all year round. In the Darwin and Katherine regions, the main fruiting period is from the middle of February to the end of April. 

In Alice Springs the main production period is from early April to the end of May.

The fruit can be ripe while the rind is still green.

Harvest

Grapefruit grown in the NT should not be left on the tree when ripe. Unlike in southern Australia, mature fruit will develop puffy skin, hollow centres and off flavours if kept on the tree for too long. 

Storage

Grapefruit will keep for three months if stored at 10 degrees Celsius.

Eating

Grapefruit juice and flesh are traditionally eaten at breakfast. They are also used to flavour and garnish food.