When to plant capsicum and chilli in Australia and New Zealand

Planting months by climate zone

Both charts come from the same data as the planting calendar. Tap a zone for its full calendar and the towns it covers. In frost areas, the first weeks of each window are for sowing seed indoors or under cover. The seedlings go out only when the soil is warm and the frosts are past.

Capsicum

Chilli

sow or plantnot recommendedthis month

The tropical window, April to July, is the dry season, because fungal diseases thrive in the wet. In the subtropics the calendar allows most of the year except late autumn and early winter. In New Zealand, chillies go in from October everywhere, and capsicums from September everywhere except the cool south.

Start the seed early and warm

Pepper seed is slow and fussy about temperature. The classic germination table by J. F. Harrington of UC Davis, republished by Oregon State University Extension, shows how much warmth speeds it up:

The minimum for germination is about 16 °C and the best is about 29 °C, so a heat mat or a warm windowsill makes a real difference in late winter. Penn State Extension recommends starting peppers 8–10 weeks before they go into the garden. In a temperate zone with an October planting, that means sowing in early August.

Planting out

• Soil above 16 °C. Penn State's rule is soil above 60 °F, about 16 °C, which is the same threshold as the cucurbits. Seedlings planted into cold soil sit still and can be overtaken by later plantings.
• After the last frost. Both crops are frost-tender. When you pick your town in the planting calendar, it flags any month that still averages a frost there.
• Spacing. 40–60 cm apart for capsicum and 40–50 cm for chilli, as in the calendar. Penn State uses about 45 cm, in rows 60 cm apart. The plant spacing calculator turns that into a plant count for your bed.
• Pots. A full-size plant needs about 30–38 litres of mix and a pot 30–40 cm deep, according to University of Maryland Extension. That is more than a standard 400 mm pot. Dwarf varieties manage with 15–23 L. See the pot size guide.

Why the flowers drop

Peppers need mild nights to set fruit. Penn State gives the range as night temperatures of 60–75 °F, about 16–24 °C, and warns that days above 95 °F (35 °C) abort the blossoms. That explains most of the timing in the charts:

• Cool zones and the New Zealand south have a short run of warm nights, so plant as early as the frosts allow and pick early varieties.
• Arid inland gardens get summer days above 35 °C, when fruit set stops. That is why the calendar there has a spring window and a second one from late summer.
• Tropical gardens grow them in the dry season, April to July, when the days are milder and fungal diseases are less active.
• Temperate gardens plant in spring. The calendar allows 10–12 weeks from planting to the first picking, so October plantings start cropping in January.

Keeping chillies for another year

Chillies are perennials in their native tropics. The Australian seed company The Seed Collection notes that many varieties grow as evergreen perennials in the tropics and die back in autumn wherever there is a winter. They start going dormant once nights stay around 10 °C. Its advice for keeping them:

• Frost-free gardens: leave the plant in the ground, cut it back hard to about 10–15 cm of main stem, and water and feed very little until spring.
• Frosty gardens: grow chillies in pots and move them to a frost-free shed, greenhouse or cool room for the winter, with only occasional watering.
• The payoff: an overwintered plant typically gives about double the first year's crop in its second year, because it starts the season with a full root system.

Capsicums can be kept the same way in frost-free gardens, but most gardeners treat them as annuals and sow fresh each year.

Questions