How to Grow Cape Gooseberries in Australia

Cape gooseberry (Physalis peruviana) is a soft-stemmed perennial in the nightshade family, Solanaceae, grown for sweet, tangy golden berries that ripen inside papery husks. It was among the first fruits the early colonists grew in New South Wales, and one sowing can crop for months. The mistake most gardeners make is growing it in soil that is too rich.

Three mistakes that matter

1. Feeding too richly. Very fertile soil and heavy nitrogen build a big, leafy bush whose fruit are slow to colour and ripen. Grow it in average soil and shift to potassium from first flowers, as Care by growth stage sets out.
2. Eating fruit before it is ripe. Unripe berries are poisonous, and the husk is bitter and inedible. Wait until the husk is papery and light brown and the berry inside is golden, as Harvesting Fruit describes.
3. Leaving windfalls on the ground. Fallen fruit can breed fruit fly, and seed from them comes up everywhere, including in nearby bushland. Gather fallen fruit every few days and deal with it as Pests and diseases describes.

When to plant

Frost decides the date. Seed germinates from about 15 to 30°C and fastest near 25°C. Start it in trays somewhere warm six to eight weeks before the last frost, then plant out once frost has passed. In frost-free zones, time sowings so fruit sets in the milder months, because summer heat slows fruit set. One sowing is usually enough, since each plant keeps flowering and fruiting while it grows.

At the early edge of a window, keep trays on a seedling heat mat. At the late edge in frosty zones, choose the Dwarf or Cossack Pineapple, which fit a pot you can move somewhere warmer.

Site, soil and setup

Rotate beds: avoid ground where potatoes grew recently, because potato moth carries over, and do not follow tomato, capsicum or eggplant, which share root-knot nematode.

Container growing

The Dwarf and the Cossack Pineapple crop well in pots. Grow one plant per pot of at least 20 L and about 35 cm across. A 45 L pot about 40 cm across dries out more slowly. Use a pot with drainage holes and a premium potting mix that meets the Australian Standard.

• Water: check daily in hot weather and water when the top few centimetres dry, because a dry plant stops growing. See watering pots in summer.
• Feed: mix a controlled release granular for containers into the potting mix at planting, at the label rate. From first flowers, give fish and seaweed blend at 25 mL per 9 L fortnightly.
• Position: full sun, out of strong wind; move the pot to a warm wall when frost threatens.

Sowing Seeds

Raise cape gooseberry in trays as you would tomato, then plant out after frost; in frost-free gardens you can also sow direct.

Starting in trays

• Sow seed about 4 mm deep in seed raising mix and keep it moist and warm, ideally near 25°C.
• Seedlings appear in 6 to 28 days, often within 2 weeks in warmth.
• Once the first true leaves show, pot each seedling into its own small pot.
• Harden off (accustom seedlings to sun and wind outdoors) for about a week.
• Plant out at 15 to 20 cm tall, at the spacing in the variety table, then water in and mulch.

Sowing direct

Where frost is rare, sow two or three seeds 4 mm deep at each planting spot in warm, moist soil. Keep the soil surface damp until seedlings appear, then keep the strongest one.

Care by growth stage

Steady moisture and a light hand with nitrogen decide the crop. Weeks count from sowing and stretch in cool weather.

In frosty zones, pull plants out once frost kills them. Where frost is light or absent, plants often reshoot and crop again, though older plants are more prone to root rots and viruses.

Companion planting

Cape gooseberry shares pests with its nightshade relatives and sprawls over anything small beside it.

Grows well with

• French marigold, planted through the bed, whose roots disrupt the life cycle of root-knot nematode.
• Sunn hemp, or a suitable oat variety, grown as a cover crop in the bed beforehand to reduce guava root-knot nematode.

Keep apart

• Potato, which hosts potato moth that moves into cape gooseberry stems.
• Tomato, capsicum and eggplant, which share tomato potato psyllid, fruit fly and root-knot nematode.
• Low vegetables and seedlings, which the spreading stems smother.

Harvesting Fruit

The first fruit usually ripen 3 to 6 months after sowing. Pick when the husk turns papery and light brown and the berry inside is clear golden yellow.

• Snap ripe fruit off by the husk, and gather fruit that has dropped, every few days.
• Pick when plants are dry; spread rain-wet fruit in the sun to dry before storing.
• Discard any fruit with a discoloured husk, which usually means the berry has broken down.
• Leave green husks on the plant: unripe berries are poisonous, and so are the leaves.

Stored in their husks somewhere cool and dry, ripe fruit keep for several weeks, and dry fruit in a sealed container can keep for months. Peel back the husk and eat the berries fresh or in fruit salad. They also cook into pies, tarts and jam, which sets well because the fruit is rich in pectin.

Common problems

Seed slow to come up. Cold mix is the usual cause, since seed germinates best near 25°C; move trays somewhere warmer and keep them moist. Read more

Plants stall or set little fruit in summer. Dry soil sends cape gooseberry dormant, and hot weather slows fruit set, so water deeply under mulch and expect more fruit as it cools.

Birds take the ripe fruit. Birds love the berries and spread the seed; cover plants with white, wildlife-safe netting pulled taut, with mesh too small for a finger. Read more

Seedlings come up everywhere. Cape gooseberry is naturalised across eastern and southern Australia, including south-west Western Australia. It is listed as an environmental weed in Western Australia, New South Wales and Victoria. Pull seedlings you did not sow, and check your council's weed list before keeping them.

Pests and diseases

Cape gooseberry shares most of its pests with tomato and potato, and any spray used must name the crop or its situation on the label.

Queensland fruit fly (Bactrocera tryoni). Found through eastern Australia, it lays eggs in ripening fruit and its maggots tunnel in the flesh, which rots. In Western Australia, Mediterranean fruit fly (Ceratitis capitata) does the same. Gather fallen fruit and destroy fly-struck fruit by sealing it in black plastic bags in the sun or freezing it for at least 24 hours. Read more

Potato moth (Phthorimaea operculella). Caterpillars mine the leaves and tunnel into the stems, so leaves on the affected branches wilt. It is worst on ground recently used for potatoes, so choose the site as Site, soil and setup describes.

Two-spotted mite (Tetranychus urticae). Yellow mottling spreads from the veins on the leaf undersides, often from midsummer, and heavy attack yellows and drops leaves. Numbers climb in hot, dry weather, so keep plants watered and avoid broad-spectrum sprays that kill predatory mites and ladybirds. Read more

Tomato potato psyllid (Bactericera cockerelli). Established in Western Australia and Victoria, this tiny sap-sucker feeds under the leaves and leaves white, sugary granules. Heavy feeding yellows and curls leaves upwards and stunts plants. Check leaf undersides weekly, and elsewhere report suspected psyllids to your state agriculture department.

Root-knot nematode (Meloidogyne species). These microscopic soil worms cause galls (lumpy growths) on the roots, and plants turn yellow, stunted and wilt. Guava root-knot nematode, found around Darwin and in Queensland, infects cape gooseberry. Bag and bin affected plants rather than composting them. Read more

Prevention first

• Gather fallen and overripe fruit every few days, through the whole season.
• Check leaf undersides weekly for mites, psyllids and leaf mines.
• Raise your own seedlings and clean boots and tools, so no infested soil comes in.
• Spare the bees: if you must use pyrethrum, spray late in the day, away from open flowers.

Tips

1. In Perth and similar dry summers, unwatered plants go semi-dormant, then regrow with the autumn rain and crop through winter and spring.
2. Where frost is light, cut old plants back after a flush of fruit to keep them going. Replace them from seed every two or three years.
3. Leave the husk on as a handle when dipping berries into melted chocolate.