How to grow Rockmelon in Australia

Where to plant

Rockmelons need the sunniest, warmest spot you have, plenty of room for the vines, and soil that drains freely. A low mound of compost and manure gives the roots rich soil and keeps the crown dry in wet weather. Seed needs warm soil to come up; in cold soil it germinates slowly and much of it rots.

The ripening fruit needs dry, hot weather to build sugar. Wet weather at ripening gives split, bland melons.

• South East Queensland and the Northern Rivers: sow from September to January.
• Sydney: sow from September to December, or start seedlings indoors in late August and plant out once the soil warms.
• Adelaide and Perth: sow from September (under cover) or October to November once the soil is warm. The hot summers ripen sweet melons; water deeply rather than often.
• Melbourne and Canberra: the season is short. Sow in October and November in Melbourne and in November in Canberra, choose early varieties and the warmest spot.
• Hobart: not reliable outdoors, as cool summers do not ripen melons. Grow it in a greenhouse.
• North Queensland and Darwin: sow in the dry season, from April to August, as wet season fruit splits and loses sweetness.

How to plant

1. Wait until the soil is warm, ideally above 18 to 20°C. Rockmelon seed rots in cold, wet soil.
2. Build low mounds of soil mixed with compost and well-rotted manure, about 1 m apart.
3. Sow two or three seeds about 2 cm deep in each mound, then keep the strongest seedling once they have a few leaves.
4. Or raise seedlings in pots and plant them out without disturbing the roots once the weather warms.
5. Water in and mulch with straw, which also keeps developing fruit off wet soil.

Watering and feeding

Water deeply at the base of the plant while the vines are growing and the fruit is filling, and keep the leaves dry to reduce mildew. Uneven watering, a dry spell followed by a soaking, makes the fruit split.

Ease back on watering in the last week or so before harvest. Much of a melon's sugar is laid down in its final week, and heavy watering then gives watery, less sweet fruit. Do not let the vines wilt badly, though, or the fruit can sunburn or ripen early.

Feed with compost and a balanced fertiliser at planting. Once fruit sets, a feed higher in potassium suits them better than more nitrogen, which mostly makes leaves.

Pruning and care through the year

• Each vine has separate male and female flowers. Only the female flowers, which have a small swelling behind the petals, make fruit, and they open for just one morning. Bees do the pollinating, so plant flowers nearby and avoid spraying while the vines are in flower.
• If bees are scarce, hand pollinate early in the morning: pick a male flower, peel back the petals and dab its pollen onto the centre of an open female flower.
• Rest each developing melon on a tile, board or thick straw to keep it clean and dry.
• Check the leaves often for powdery mildew, and pick off the worst affected leaves.

Harvesting

A rockmelon is ripe when the skin under the netting turns from green to golden, the stem end smells sweet, the tendril nearest the fruit dries off, and a crack forms around the stalk so the fruit slips off the vine with gentle pressure. This is called full slip.

Melons do not get any sweeter once picked, so wait for these signs. Keep a ripe melon on the bench for a day or two, then in the fridge for three or four days.

Growing in pots

Rockmelons are not well suited to pots, as the vines are large and hungry. If you only have a pot, use the biggest you can (50 cm or more), choose a small-fruited variety, and grow it up a sturdy trellis with each fruit supported in a sling.

Using it

Eat rockmelon fresh, in fruit salads, with prosciutto, or blended into smoothies and sorbets. Wash the netted skin before cutting, as it can carry soil and bacteria onto the flesh.