September is easily the biggest month of the year here — 34 sowing windows are open at once, more than any other month this site tracks for this zone. It's also the month this zone's frost risk closes for the year, and the one month feijoa, lime and passionfruit all get their planting window.

Quick Answer: What to Sow Now

Thirty-four crops are open for sowing this September: basil, beans (climbing), beetroot, broad beans, broccoli, brussels sprouts, capsicum, carrot, coriander, courgette, cucumber, eggplant, feijoa, jerusalem artichoke, kale, lemon, lettuce, lime, mandarin, mizuna, mustard greens, onion, orange, pak choy, passionfruit, peas, pumpkin, radish, shallot, silverbeet, spinach, tomato, turnip and yacon.

New This Month: Feijoa, Lime and Passionfruit

Feijoa and lime both move into their September–November planting window this month, going in as potted nursery stock — Best Feijoa and Best Lime Varieties cover cultivar choice. Passionfruit sows this month too, and it's a genuinely different case: it's one of only two crops in this project's data with no outdoor growing window in NZ's other zones at all, so this September window is unique to this zone rather than simply earlier than everywhere else. Best Passionfruit Varieties has the cultivar detail.

The Last Frost-Tender Direct Sows

Courgette, pumpkin and climbing beans all open this month, direct sown once frost risk has passed. Courgette (sowing September–December) needs at least two plants for reliable pollination, spaced a metre apart — Black Beauty (Kings Seeds NZ) is the sourced cultivar. Pumpkin (September–November) is a long-season crop at 100–160 days, with Atlantic Giant (Kings Seeds NZ) and Austrian Hulless (Koanga Institute) both sourced. Climbing beans (September–December) need a support structure in place before sowing — America (Koanga Institute) and Anasazi (Kings Seeds NZ) are the sourced picks.

The Classic Spring Trio

Peas, spinach, lettuce and carrot all open their sowing windows this month, alongside basil (already running since July). Peas run September through February, direct sown, fixing their own nitrogen. Spinach runs the same window, bolting in heat rather than minding the cold. Lettuce reopens after closing in March, running all the way through to next March — succession sow every 2–3 weeks rather than one large batch. Carrot opens its own September–May window too; direct sow only, since transplanted carrots fork.

New Brassicas: Brussels Sprouts and Mustard Greens

Both open a short September–October window only. Brussels sprouts need raising in trays and netting against white butterfly from transplanting. Mustard greens can go the same route or be direct sown for a quicker baby-leaf harvest.

Perennial Tubers Go Back In

Jerusalem artichoke and yacon both open their planting window this month — a different moment to the harvest windows covered in earlier months' articles. Plant Jerusalem artichoke tubers once soil warms past 15–16°C; plant yacon crown divisions roughly 40cm apart into compost-enriched soil, both after frost risk has passed.

Last Call This Month

Onion (open since July) and shallot (since August) both close their sowing windows at the end of September. So do capsicum, eggplant and tomato — all three started back in June, making this their final month to go in if you haven't already.

Everything Else Still Running

Beetroot, broad beans, broccoli, coriander, cucumber, kale, lemon, mandarin, mizuna, orange, pak choy, radish, silverbeet and turnip all remain open with nothing new to flag this month.

Also Harvestable This Month

Tamarillo is the only crop harvestable now that isn't also sowable, cropping through to November.

Timing Notes for Sub-Tropical Gardens

September closes out this zone's May–September frost window — the same bookend, in reverse, as May's opening. That's exactly why onion, shallot, capsicum, eggplant and tomato all make their last call this month, and why feijoa, lime and passionfruit are timed to go in as frost risk properly clears rather than earlier.

Recommended Cultivars

  • Basil — Cinnamon (Kings Seeds NZ), Genovese (Koanga Institute)
  • Beans (Climbing) — America (Koanga Institute), Anasazi (Kings Seeds NZ)
  • Beetroot — Bull's Blood (Kings Seeds NZ, Koanga Institute)
  • Broad Beans — Coles Prolific (Kings Seeds NZ), Red Seeded (Koanga Institute)
  • Broccoli — Belstar F1 (Kings Seeds NZ), de Cicco (Koanga Institute)
  • Carrot — Akaroa Long Red (Koanga Institute), Amsterdam Sprint (Kings Seeds NZ)
  • Coriander — NZH (Koanga Institute), Picante (Kings Seeds NZ)
  • Courgette — Black Beauty (Kings Seeds NZ)
  • Cucumber — Amira F1, Crunchy F1 (both Kings Seeds NZ)
  • Kale — Blue Ridge F1 (Kings Seeds NZ), Borecole (Koanga Institute)
  • Lettuce — Buttercrunch, Coral Red (both Kings Seeds NZ)
  • Peas — Alderman Tall Climbing (Kings Seeds NZ), Amish Snap (Koanga Institute)
  • Pumpkin — Atlantic Giant (Kings Seeds NZ), Austrian Hulless (Koanga Institute)
  • Silverbeet — Bright Yellow, Ford Hook Giant (both Kings Seeds NZ)
  • Spinach — Bloomsdale (Kings Seeds NZ), Japanese/Lands End (Koanga Institute)
  • Tomato — Albenga Oxheart (Kings Seeds NZ), Alma (Koanga Institute)

The remaining sowable crops this month — brussels sprouts, capsicum, eggplant, jerusalem artichoke, lemon, lime, mandarin, mizuna, mustard greens, onion, orange, pak choy, passionfruit, radish, shallot, turnip and yacon — don't yet have a sourced cultivar recommendation for this zone.

Know your zone? Explore the full NZ Sub-Tropical Planting Calendar for month-by-month sowing and harvest timing.