What to Sow in September: Vegetables for Every Australian Zone

The short version: September is spring proper across most of Australia, and for many gardens it brings the longest sowing list of the year. Leafy crops, roots and peas can go in almost everywhere, while beans, sweetcorn and the cucurbits need warm soil first, commonly quoted from about 16°C and higher again for zucchini and pumpkin. Let the last frost and the feel of the ground set the timing, not the date.

There is a morning in early September when the garden smells different. The soil gives off that damp, faintly sweet smell it keeps to itself all winter, and the bed looks like it is waiting.

That is a good cue to read. The trick is knowing which half of the seed box the morning means, because September asks for two different kinds of sowing at once.

Soil warmth decides the date, not the calendar

Put a hand flat on the bed before you open a packet. Cold ground stalls a warm-season seed no matter how bright the day looks above it.

Beans, sweetcorn and cucumber are commonly listed as sowing from a soil temperature of around 16°C, while zucchini and pumpkin want warmer ground, often quoted from about 20 to 21°C. Below those figures seed tends to sit, and in cold wet soil it can rot rather than sprout.

Cool-season crops work the other way. Peas, lettuce, beetroot and carrot are usually given starting temperatures from around 7 to 8°C, so they go in weeks before anything in the bean seeds or corn seeds range is worth risking.

Frost is the other half of the answer, and it is stubbornly local. Two gardens in one suburb can differ by a fortnight, and a low-lying bed holds frost long after the town has finished. The Bureau of Meteorology's potential frost days maps are a good check on your own patch.

Cool zones: the frost still has the last word

In cool and tableland gardens, September is a direct-sowing month for hardy crops and an undercover month for the rest. Hobart, Canberra, Ballarat, Katoomba and Armidale sit here.

Direct sow beetroot, carrot, kale, lettuce, peas, radish, rocket, silverbeet, spinach, spring onion, swede and turnip. Undercover, start tomato, capsicum, chilli and eggplant, and by late September get cucumber, zucchini and pumpkin going in pots.

Hold back beans, sweetcorn and the cucurbits until the frosts finish and the ground genuinely warms, often October rather than September.

Temperate zones: the longest list of the year

Temperate gardens get the widest September list in the country, and it opens in two waves. Sydney, Melbourne, Adelaide, Geelong, Newcastle and Perth sit here.

• Early September: beetroot, carrot, celery, lettuce, radish, rocket, silverbeet and spring onion.
• Mid to late September, once frost is behind you: beans.
• Late September: cucumber, pumpkin, sweetcorn and zucchini.
• Tomato, capsicum, chilli and eggplant undercover early, out or direct late.

Perth and southern WA are worth calling out. Winter rain tails off and summer arrives dry, so September sowings do better with mulch and steady watering than with a hopeful glance at the sky.

Hold the cucurbits back in colder pockets and inland districts. A week of patience beats replacing a punnet of zucchini seeds.

Subtropical zones: everything at once, briefly

Subtropical gardens can sow almost the whole warm-season list in September, the busiest month of their year. Brisbane, the Gold Coast, the Sunshine Coast and Coffs Harbour sit here.

Beans, beetroot, capsicum, chilli, carrot, cucumber, eggplant, lettuce, melons, pumpkin, radish, rosella, silverbeet, spring onion, squash, sweetcorn, tomato and zucchini can all go in, with okra worth leaving until late. Anything empty suits a warm-season cover crop.

Hold back peas and other cool-season crops, which bolt once the humidity settles in.

Tropical zones: shorter lists as the build-up begins

Tropical gardens shift to heat-tolerant crops in September, usually the first month the build-up makes itself felt. Darwin, Cairns and Townsville sit here, and warmer nights with higher afternoon humidity are the giveaway.

Snake beans, capsicum, chilli, cucumber, eggplant, okra, pumpkin, radish, rosella and sweetcorn all suit the month, with melons better sown early. Mulch and shade cloth matter more now than any extra crop.

Hold back anything long and leafy that must survive the wet.

Arid zones: a second big window, and it closes fast

Arid and semi-arid gardens get a genuine second sowing window in September, but the heat arrives fast behind it. Alice Springs, Broken Hill, Mildura and Kalgoorlie are the markers.

Beetroot, carrot, cucumber, lettuce, radish, silverbeet and spring onion go in early, beans from about mid September once frost has passed, and melons, pumpkin, sweetcorn and zucchini late. Tomato, capsicum and chilli are usually planted out in late September.

Hold back slow crops that would still be sizing up when the heat hits.

Seed potatoes are in their window too

September is a good seed potato month across much of the country, though timing shifts by zone. Cool gardens can plant chitted tubers as the frosts ease, usually late September into October. Temperate gardens are in their prime, subtropical gardens at last call.

Due to quarantine restrictions and our shipping policy, we cannot send seed potatoes to Western Australia, Tasmania or Kangaroo Island. Elsewhere, our guide to chitting seed potatoes covers the sprouting-on-the-windowsill stage.

Sow in waves, not in one afternoon

The most common September regret is not sowing too late, it is sowing everything on the same warm Saturday. A bed that goes in at once comes ready at once, and the kitchen pays for it in January. Splitting your vegetable seeds into two or three sowings a fortnight apart usually gives steadier picking, and a soft landing if a late frost takes the first round. Our guide to spring sowing in Australia sets out the timing zone by zone, and our zone finder takes your postcode.

Frequently asked questions

Is September too late to sow peas?

In cool and temperate gardens September is usually still fine, though the window closes as the weather warms. In subtropical and tropical zones, leave peas until autumn.

What soil temperature do beans and sweetcorn need?

Both are commonly listed as sowing from around 16°C soil temperature. Zucchini and pumpkin want warmer ground, often quoted from about 20 to 21°C, so they usually come a few weeks later.

Can I sow tomatoes outside in September?

In warmer zones, yes. In temperate gardens tomatoes are often started undercover early and moved out late, and in cool gardens they stay undercover until the frosts finish.

Why did my September beans fail to come up?

Cold, wet soil is the usual cause. Bean seed sown below its preferred range can rot rather than germinate, so a resow once the soil warms often does better.

Does September work for Perth gardens?

Yes. Perth and southern WA sit in the temperate group and get the full September list. The difference is what follows, since summer arrives dry, so mulch and steady watering count.

How do I know when my last frost has passed?

Local knowledge is the best guide, backed by the Bureau of Meteorology's frost maps. Frost is highly localised, so a neighbour two streets away can have a different answer.