How to grow physalis (Cape gooseberries)

Physalis, also called Cape gooseberry or goldenberry, comes from the Andes and is killed by frost. It needs a long season to ripen its fruit, so start it indoors in March or April, much like tomatoes, and plant it out once the last frost is past: mid to late May in most of Germany, Austria, Switzerland and the UK.

In frost-free climates physalis is a perennial shrub. Here it is usually grown as an annual. In the very mildest parts of the UK it can survive winter outdoors if you cut back the frosted top and mulch the roots, but don't count on it.

Sow the tiny seeds thinly on moist seed compost and only just cover them, no deeper than about 0.2–0.4 in. Keep them warm at 68–77°F; they usually come up within 7 to 10 days. Prick the seedlings out into individual pots once they are big enough to handle, and keep them in a bright spot.

Harden the young plants off before planting them out after the last frost. Give them a sunny, warm, sheltered spot with free-draining soil; sandy loam is ideal. A cloche or fleece in the first weeks helps them settle in during cool spells.

Physalis grows into a branching bush about 3–5 ft tall, so give it plenty of room and don't squeeze it between other plants. It can also be grown in a greenhouse, which helps the fruit ripen in a cool summer.

Water in dry spells and keep the soil evenly moist, but not wet; physalis dislikes waterlogged roots.

Flowers appear through summer, and each one develops a green, lantern-shaped husk with a berry growing inside. Fruit ripens gradually from late summer, so you pick a few at a time over several weeks.

Physalis ripens from about August until the first frost. A fruit is ready when its husk has turned dry, papery and straw-coloured and the berry inside is golden orange. Ripe fruits often drop from the plant on their own, so check underneath too.

Only eat fully ripe berries. Unripe fruit, leaves, stems and flowers contain solanine and related alkaloids, and the husk itself is not edible either.

Left in their husks, the berries keep for several weeks at room temperature and often much longer somewhere cool and dry. Pick carefully so the husk stays intact.

Several plants share the papery lanterns. The Cape gooseberry, Physalis peruviana, is the one sold as "physalis" in shops, with sweet-sour golden berries.

The Chinese lantern, Physalis alkekengi, is a hardy ornamental perennial with bright orange-red lanterns that are popular in dried arrangements. Its green parts are mildly toxic, opinions on its berries differ, and its creeping roots can spread hard to control. Don't grow it as a fruit.

The tomatillo, Physalis philadelphica, has larger green or purple fruits that fill and often split their husks. It is used cooked, for example in salsa verde, and needs at least two plants to set fruit well.

Whitefly is the most common pest, especially in greenhouses; spider mites turn up in hot, dry conditions. Leaf spots, powdery mildew and root rot on wet soil can also occur.

Physalis belongs to the nightshade family with tomatoes, potatoes, peppers and aubergines, and shares some of their pests and diseases. Leave three to four years before any of them grows in the same bed again.

We found no reliable studies on companion plants for physalis. Treat any pairing lists as tradition.

The practical rule: give it a sunny, open spot of its own, and keep it apart from other nightshades in your rotation.