Asian melons

Facts and figures

• Asian melons are members of the Cucurbitaceae plant family
• They are grown in hot humid climates
• The Northern Territory is the major region producing Asian melons in Australia
• Production practices are similar to other cucurbit crops — most are grown on mounds and trellises
• Harvest timing of Asian melon is critical to ensure optimum quality
• Harvesting Asian melons is labour intensive
• Australian production of Asian melons is consumed entirely domestically as fresh produce
• Luffas can be grown to maturity to be used as sponges but there is limited production of this type in Australia

Production status

Publicly available production figures for Asian melons in Australia are difficult to obtain. In the Northern Territory, the major production area in Australia, the production of long melons generally exceeds luffas, which exceeds winter melon. Prices vary greatly depending on the quality of the product and seasonality of the supply.

Map of current and potential growing regions

When picked early (less than 12cm in length) luffa fruits are usually cooked or fried and used in soups, or sliced and dried for later use. Very small fruits can be eaten raw or pickled.

Mature fruits of the smooth luffa are washed to remove the rind and remaining flesh. The remaining fibrous material is then dried and treated to be used as sponges. They are commonly used in bath products in Australia but have been used in Asia as pot scrubbers, in mats, slippers and mattress stuffing, and they can even be used as engine filters!

Winter melons can be grown at high densities on trellising but are usually grown prostrate on mounds on the ground at lower densities as they produce quite large fruits. Producers in the Northern Territory that grow winter melons on the ground, have 60–80cm between plants and 1.5 metres between rows. This density requires about 2kg/ha of seed but higher densities can be used if growing the melons on trellises. The mounds may be covered with mulch or plastic for weed control and moisture retention. Production on mounds can also prevent waterlogging. Winter melons need a lot of organic matter and some nitrogen–phosphorus–potassium (NPK) fertiliser at planting plus some side-banded nitrogen until flowering. While winter melons are drought tolerant, maximum production is achieved with irrigation in regions with low rainfall.

Agronomic requirements for hairy melon are essentially the same as for winter melon, as the two melons are variations of the same species. Note the use of trellising can produce more uniform fruit, prevent wind rub damage, prevent the fruit touching the ground and developing fruit rot and discolouring. Trellising ensures uniform growth of the melons as they hang down and it has been observed that trellising can also produce larger fruit.

Luffas, like the hairy and winter melons, are grown on trellises placed on mounds of soil. The trellises are usually about 2m high. Smooth luffa can be planted in a rectangular system 100cm by 100cm, while angled luffa can be planted up to 20cm closer. Both crops are best grown on trellising, though angled luffa can be grown prostrate. Luffas need a lot of NPK fertiliser plus side banding of nitrogen up to flowering. However, it should be noted that too much nitrogen in combination with high temperatures encourages excess male flowers thus reducing yields. Luffas are not drought tolerant and need irrigation in dry periods. Smooth luffas are more resistant to waterlogging than angled luffas.

As all the Asian melons are cucurbits they have male and female flowers, and the presence of bees greatly assists pollination and fruit set. The proportion of female flowers may increase with cooler and shorter days. Spraying of insecticides should be carefully monitored so as not to affect the crop pollinators.

For further information on planting and crop management of bitter melon refer the Northern Territory Government Fact Sheet Asian Melons.

Weeds, pests and diseases

Both luffas and winter melons are relatively insensitive to most pests and diseases, however powdery mildew and downy mildew may cause problems if left uncontrolled. The major insect pests are fruit flies and aphids. Cucurbits are susceptible to viruses and aphid control is important as they are carriers of various viruses. Nematodes, particularly root knot nematodes, can affect all of these melons and it is important to use a crop rotation with non-susceptible crops, use of an off-season green manure crop may also help in the management of nematodes. Some growers plant alternate rows in their cropping systems to provide a break for soil health benefits.

Winter melon is particularly robust against disease and is sometimes used as rootstock for other cucurbit crops.

No pesticides or herbicides are specifically registered for use on Asian melons in Australia, however off-label use permits are available. It is necessary to check with the relevant state department for current permits.

For further information on diseases and insect pest of cucurbits and their management refer to the NSW DPI Primefacts Diseases of cucurbit vegetables  and Insect pests of cucurbit vegetables .

Hairy melons are preferred small, solid and green. The hairy surface of hairy melon should not be washed off as it is a gauge of the melon’s freshness. The fruit should be stored carefully at around 10–12.5°C as it is susceptible to chilling injury, the packaging should be well ventilated to avoid the build-up of ethylene which can enhance ripening of the fruit.

Luffas need to be handled gently if they are to be picked for eating. It is important to remove the field heat from the melons as rapidly as possible once they have been picked; the retained field heat may be reduced if the melons are picked in the cool of the day. The melons can be stored for 2–3 weeks at 12–16°C.

Sponges are harvested from smooth luffas at maturity, 4–5 months after planting. Smooth luffas can produce up to 20–25 fruits per plant whilst angled luffas can produce 12–20. Both types of melons weigh between 0.2–0.8kg per fruit.

If processing a luffa to produce a sponge, the fruit is immersed in water until the rind dissolves and the pulp and seeds are washed out. The remaining fibrous material is bleached with hydrogen peroxide and dried in the sun.

Some producers of Asian melons choose to participate in Freshcare, which is currently the largest Australian on-farm assurance program for fresh produce for on-farm food safety and quality and environmental certification services.

When processing raw product into value-added food products, consideration should be given to food standards regulations. Further information can be found at the websites of Freshcare, HACCP and Food Standards Australia New Zealand.

Quarantine issues may need to be addressed if Asian melons are marketed interstate.

Another regulatory consideration relates to the use of pesticides as there are currently no pesticides registered for use on Asian melons in Australia, however off-label use permits are available. It is necessary to check with the relevant state department for current permits.

Other resources

Freshcare is an industry owned, not-for-profit on-farm assurance program, established and maintained to service the Australian fresh produce industry.

HACCP Australia  is a leading food science organisation specialising in the HACCP Food Safety Methodology and its applications within the food and related non-food industries.

Food Standards Australia New Zealand is a bi-national Government agency. It develops and administers the Australia New Zealand Food Standards Code, which lists requirements for foods such as additives, food safety, labelling and GM foods. Enforcement and interpretation of the Code is the responsibility of state and territory departments and food agencies within Australia and New Zealand.

Northern Territory Farmers Association is the peak body for the Plant Industry in the Northern Territory and is an amalgam of the former Northern Territory Agricultural and Horticultural Associations.