Mid-May is the right moment to make the overwintering decision on chilli plants in southern Australia. The autumn temperatures have dropped enough that the productive growth is essentially over for the year, the late fruit is ripening on existing flowers, and the plant is heading into a dormant phase that the grower can either work with or ignore. The growers who plan the overwinter through May tend to have stronger early-season plants in September. The growers who leave the plants outside until the first frost tend to be starting from seed again in October.

The basic decision is whether the plant is worth overwintering. The honest answer is “sometimes.”

Annuums — the bell-and-jalapeno family, capsicum annuum — are technically perennial in mild climates but the second-year performance is generally not better than starting fresh from seed. The plants are messier in their second year, the fruit set is variable, and the disease load is higher. Most growers replant annuums each year and get a cleaner crop.

Chinenses — the habanero family, including most of the superhots — are worth overwintering in the southern climates because the time from seed to fruit is long enough that a second-year plant is fruiting in October-November while a fresh seedling is still in pots. The chinense overwinter pays back.

Frutescens (tabasco-type) and baccatum (aji-type) are in the worth-overwintering category for the same reason.

The May to August overwintering procedure that works in southern Australian conditions:

Prune the plant back hard. A second-year chinense should come down to a basic stem framework — main stem and three to five primary branches, cut back to the woody section. All leaves come off. All remaining fruit and flowers come off. The plant looks dead. It is not dead.

Repot in fresh, well-drained mix. The old soil has spent its season. The new mix should be free-draining, with a mild slow-release fertiliser. The pot size should be reduced rather than increased — overwintering plants want a small root mass, not a generous one.

Move to a sheltered, dry, cool position. The plant wants 5-15°C overnight, dry conditions, and minimal water. A glasshouse is ideal. A sheltered north-facing porch is workable. A bright windowsill in a cool room is acceptable. The plant should be watered sparingly — once a fortnight, just enough to keep the root ball from drying completely.

Watch for pests. The aphids and the spider mites that find their way to the overwintering plant in July are the biggest cause of overwinter failure. A regular inspection and a soap-spray treatment at first sign is the answer.

In August, the plant gets the wake-up. The light increases, the temperatures start climbing, and the plant should be moved to a brighter, slightly warmer position with a small increase in watering. The first new growth typically appears by late August. The plant should be back to full feeding by mid-September.

Three common mistakes:

Leaving the plant outside through winter in expectation of mild weather. The plant is fine until the first hard frost, at which point it is dead. The overwintering plan needs to be inside.

Overwatering during the dormant phase. The leading cause of overwinter failure is root rot from too much water in too cool a pot.

Forgetting to prune. The unpruned plant either does not survive or comes through with an awkward, leggy shape that the grower spends the spring trying to correct.

The 2026 climate context in southern Australia is that the autumns have been mild and the winters have been variable. The plants that come inside in mid-May survive cleanly. The plants left out until June are gambling.

The overwintering chilli is a good plant. The varieties that take three years to mature into proper bushes — some of the chinense lineages — are worth the work. The growers with three- and four-year-old plants are getting fruit set and flavour that no one-year plant can match.