Garlic rejoins the sowing list this month, and the sourced timing is genuinely distinctive: sub-tropical gardeners plant it earliest of NZ's three zones, going in a full two months ahead of the cool/mountain zone. That's not an accident of the data — mild winters here give garlic less natural cold-chilling, so an early autumn start is what keeps rust risk down instead.

Quick Answer: What to Sow Now

Seven crops are open for sowing this March: beetroot, carrot, garlic, lettuce, pak choy, radish and silverbeet.

Garlic — This Zone's Earliest Start in NZ

Garlic's sowing window here runs March through April — a full two months ahead of the cool/mountain zone's May–June window, and a month ahead of temperate's April–May. The reasoning is specific to this zone's climate: mild winters don't give garlic the cold-chilling that colder zones provide naturally, so planting early in autumn is what substitutes for it and keeps rust risk manageable, rather than the crop needing the longest possible chill period the way it might further south.

Plant cloves 5cm deep, 15cm apart, for a roughly seven-month run through to an October–November harvest. Two Koanga Institute varieties are sourced for this zone: Elephant Garlic, spaced 15cm on the diagonal, with its flower heads worth removing while young to put the plant's energy into the bulb; and Rocombole Early Red, on tighter 10–12.5cm diagonal spacings. If garlic rust has been a problem in your garden before, Rust and White Rot in NZ Garlic is worth reading alongside this early-planting timing, since the two are directly connected here.

Because this is the earliest garlic goes in anywhere in the country, the bed needs to be ready now rather than scrambled together at planting time. Clear whatever summer crop was in that spot, work in compost ahead of planting, and choose a spot with good drainage — garlic planted into heavy, still-wet soil this early in the season is more exposed to the fungal pressure an early start is meant to reduce, not less.

The Rest of This Month's Sowing

Beetroot, carrot, radish and silverbeet are all well inside their long sowing windows and don't need anything special this month — direct sow all four, keeping carrot beds evenly moist through germination.

Lettuce and pak choy are past the worst of the summer bolting pressure that shaped January and February's sowings, though both still benefit from some shade while the heat properly breaks. Succession-sow lettuce every 2–3 weeks rather than committing a whole bed at once.

Where Sub-Tropical Is Wrapping Up

Climbing beans close out their harvest window here this month (December–March) — the opposite position to the temperate zone, where climbing bean harvest only opened in February and still has two more months to run. If you've got beans still on the vine, this is the month to clear them rather than expect much more.

Also Harvestable This Month

March also opens the harvest window for feijoa (running through to July) and keeps a long list of other crops cropping: basil, broccoli, capsicum, courgette, eggplant, onion, passionfruit, peas, pumpkin, spinach and tomato. Broccoli and onion are both nearing the end of their harvest windows this month, so prioritise picking over letting either sit.

Timing Notes for Sub-Tropical Gardens

This zone's frost risk doesn't open until May, so nothing in this month's sowing list is frost-limited — garlic's early start is about chilling and rust pressure, not cold protection. March generally reads as a transition month here: summer's bolting pressure is easing for the leafy greens, and garlic's arrival is the first real signal that autumn planting has begun in earnest.

Recommended Cultivars

  • Beetroot — Bull's Blood (Kings Seeds NZ, Koanga Institute)
  • Carrot — Akaroa Long Red (Koanga Institute), Amsterdam Sprint (Kings Seeds NZ)
  • Garlic — Elephant Garlic, Rocombole Early Red (both Koanga Institute)
  • Lettuce — Buttercrunch, Coral Red (both Kings Seeds NZ)
  • Silverbeet — Bright Yellow, Ford Hook Giant (both Kings Seeds NZ)

No approved cultivar picks are recorded yet for pak choy or radish in this zone's sourcing.

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