September is spring's second big sowing month, and the sowing list grows longer than at any other time of year. Peas, lettuce, spinach and carrots all reopen in every region, and onion, shallot and citrus make their last call. What divides the country is frost. In Northland and Auckland, the frost season ends this month, and the summer crops — courgette, pumpkin, climbing beans — start going outside. Everywhere else, frost runs until November, and the tender crops stay indoors for now.

Quick Answer: Plant These Anywhere in NZ

Twenty-seven crops are inside their planting window in every NZ growing zone this September.

Opening this month:

  • Peas (sow September–February)
  • Lettuce (sow September–March)
  • Spinach (sow September–February)
  • Carrot (sow September–May)
  • Brussels sprouts and mustard greens (sow September–October only)
  • Basil (sow September–February; open since July in the sub-tropical zone)
  • Feijoa and lime (plant September–November, as potted nursery stock)

Last month to sow or plant:

  • Onion (July–September) and shallot (August–September)
  • Lemon, mandarin and orange (April–September)

Still open from August: beetroot, broad beans, broccoli, kale, silverbeet, radish, pak choy, mizuna, turnip, coriander, and tomato, capsicum and eggplant in trays.

Notes from the planting data

  • Peas are direct sown and fix their own nitrogen, so the bed doesn't need heavy feeding. For variety choice, see Best Peas for NZ Spring.
  • Lettuce is best sown in short succession rows every two to three weeks.
  • Spinach is frost-hardy and bolts in heat, not cold, so this cool end of its window is the easy one.
  • Carrot is direct sow only. Germination is slow in cool soil, so keep the seedbed moist.
  • Brussels sprouts have a short window. Raise them in trays, transplant at four to six weeks, and net against white butterfly from the start.
  • Mustard greens can be tray-raised and transplanted at 6–8cm, or direct sown for a quicker baby-leaf harvest.
  • Basil is frost-tender. Outside the far north, start it indoors and transplant only after the last frost.

Broccoli and kale sown in August can be transplanted now (broccoli until December, kale until November). Net them as soon as they're planted — see White Butterfly and Cabbage Moth on NZ Brassicas. For feijoa and lime variety choice, see the feijoa and lime guides.

On the harvest side, coriander, mizuna and turnip start cropping in every zone, along with pak choy (September–June). Pull turnips as they size up, since they turn woody once summer heat arrives. Mandarin finishes this month. Lemon and orange carry on until November.

Not sure which zone you're in? The NZ frost dates guide covers it by town.

Sub-Tropical: Northland, Auckland and Coastal Taranaki

September is the far north's biggest month: 34 crops are in their window. The frost season here ends in September, so the frost-tender summer crops start going outside:

  • Courgette (sow September–December) — the planting-window notes advise at least two plants, a metre apart, for reliable pollination.
  • Pumpkin (sow September–November) — a long-season crop at roughly 100–160 days.
  • Climbing beans (sow September–December) — put the support structure in before sowing.
  • Passionfruit (September–November) — this zone has the only outdoor window for it in NZ. See passionfruit varieties.
  • Jerusalem artichoke and yacon (both September–October) — plant tubers and crown divisions after the last frost. Yacon goes in about 40cm apart, in compost-enriched soil.

Tomato, capsicum and eggplant make their last call for sowing this month (June–September). Their transplant window runs until October. Cucumber and basil seedlings can go out now too (cucumber September–December, basil September–February). Tamarillo trees can be planted from September to November, and the tamarillo harvest continues until November.

Temperate: Most of the Country

The 27 crops above are the September list. Frost season here runs until the end of November, so a mild September week is not the last frost. Keep basil and the tomato family indoors until the risk has properly passed.

Courgette, cucumber and pumpkin aren't open yet here. Cucumber opens in October, and courgette and pumpkin in November. September is the month for climbing peas, so get a trellis up before the plants start scrambling. Onion and shallot both close at the end of the month. If you miss them now, you wait until next winter.

Cool/Mountain: Central Otago, Queenstown and the Central Plateau

In cool/mountain gardens, the 27-crop list is identical, but spring arrives colder and later here. Frost runs until the end of November, and returns as early as March. Two things follow:

  • Direct-sown seed is slow. A carrot or pea row can sit a fortnight before showing. Peas are recorded as frost-tender, so young plants benefit from a cloche in the hardest-frost gardens.
  • Tender crops get a short season. Basil's harvest here runs only January to March, so start it early under cover. Then it's ready to go out the moment the last frost passes.

Broccoli and kale can be transplanted, but in the coldest gardens hold them back if hard frosts are still coming through. A transplant checked by cold recovers slowly. Brussels sprouts and kale both improve in flavour after frost, which this zone delivers reliably.

Recommended Cultivars

These cultivar picks for September's sowings come from NZ suppliers:

  • Peas — Snow Goliath, Snow Shiraz (Kings Seeds NZ); Southland Sno (Koanga Institute)
  • Lettuce — Parris Island Cos, Salad Bowl Green, Salad Bowl Red (Kings Seeds NZ)
  • Spinach — Bloomsdale, Winter Upright F1 (Kings Seeds NZ); Japanese (AKA Lands End) (Koanga Institute)
  • Carrot — Tendersweet (Kings Seeds NZ); White Belgium, Oxheart (Koanga Institute)
  • Broccoli — Summer Green F1, Sprouting Winter Rudolph (Kings Seeds NZ); de Cicco (Koanga Institute)
  • Kale — Tuscan Black, Westerland, Squire (Kings Seeds NZ)
  • Broad beans — Scottish, Red Seeded (Koanga Institute)
  • Basil — Thai Siam Queen, Mrs Burns Lemon (Kings Seeds NZ)
  • Tomato — Baxters Early Bush, Ananas Noire (Kings Seeds NZ)
  • Sub-tropical summer crops — Courgette: Cocozelle (Kings Seeds NZ). Pumpkin: Queensland Blue (Kings Seeds NZ). Climbing beans: Dutch, Crystal French (Koanga Institute).

There are no approved cultivar picks yet for Brussels sprouts, mustard greens, onion, shallot, capsicum, eggplant or the fruit trees.

September Garden Jobs, Anywhere in NZ

These are general spring jobs, not zone-sourced planting data:

  • Harden off seedlings for a week or so before they go outside.
  • Put supports in first. Trellises for peas and climbing beans are far easier to install before sowing than around tangled plants.
  • Net brassicas at transplanting, not at the first sign of caterpillars.
  • Plant out by the calendar, not the weather. One warm week isn't the end of frost season anywhere outside the far north.

Next Steps

For month-by-month sowing and harvest timing in your area, see the full planting calendar for your zone: