March is the hinge month in New Zealand's temperate garden — summer crops are still cropping hard, but the sowing window is narrowing fast. Frost isn't a factor yet here (the temperate zone's frost-risk period doesn't start until April), but a handful of crops close their sowing windows this month regardless.

The NZ Temperate March Growing Context

Soil is still warm from summer, which keeps germination quick, but nights are noticeably cooler than in January and February. That combination — warm soil, shorter days — actually favours several autumn crops over a midsummer sowing, since seedlings aren't fighting heat stress or bolting.

Typical March conditions in temperate gardens:

  • Warm soil, cooling nights
  • Shortening days slowing summer crops
  • Still frost-free — the temperate zone's frost risk runs April through November
  • Heavy ongoing harvests from tomatoes, courgettes and cucumbers
  • Last realistic window for a few key sowings

What to Sow This Month

Beetroot

Beetroot's sowing window runs August through May in the temperate zone, so March is comfortably inside it. Direct sow and thin seedlings to around 10cm apart — beetroot dislikes being transplanted, so don't raise it in trays. It tolerates light frost, which matters less this month but helps it carry into the cooler weeks ahead.

Cultivar pick: Bulls Blood (Kings Seeds NZ) — deep red foliage as well as roots, suited to both autumn and spring sowing.

Carrot

Carrot's window runs September through May, so there's still time for an autumn sowing. Direct sow only — carrots don't transplant — and keep the seedbed evenly moist until germination, which is the single biggest factor in getting an even stand rather than a patchy one.

Cultivar picks: Amsterdam Sprint (Kings Seeds NZ), a fast, reliable all-rounder; or Akaroa Long Red (Koanga Institute), a heritage long-rooted type worth trying if your soil is deep and loose.

Lettuce — last call this season

Lettuce's sowing window closes at the end of March in the temperate zone, so this is the final succession sowing before the gap until spring. Direct sow or raise in trays, and keep up the every-2-to-3-week succession rhythm one last time rather than sowing a single large batch.

Cultivar picks: Buttercrunch or Coral Red (both Kings Seeds NZ) — both cope well with the cooler end of the sowing window.

Silverbeet

Silverbeet's window runs August through May, so it's a safe autumn choice — it's one of the few crops here that will genuinely grow through winter once established. Direct sow, or raise in trays if you'd rather transplant into gaps left by finished summer crops.

Cultivar picks: Ford Hook Giant (Kings Seeds NZ) for a heavy-cropping standard; Bright Yellow (Kings Seeds NZ) if you want colour in the bed as well as the plate.

Not yet: Broccoli, Kale and Garlic

All three are on gardeners' minds by March, but the data doesn't support sowing any of them yet. Broccoli's window opens in August, kale's in August, and garlic doesn't go in until April — next month. Sowing brassicas this early means they mature into the shortest, coldest weeks of winter instead of establishing steady growth first. Hold off.

What to Harvest This Month

March brings a wide harvest, spanning both the last of summer and the first of the newer sowings:

  • Tomatoes — pick every few days; cooler nights slow ripening, so bring on any close to colour if a cold snap is forecast.
  • Courgettes and cucumbers — pick young and often while still cropping.
  • Beans (climbing) and peas — both harvest through to May; keep picking regularly.
  • Pumpkin — harvest window opens this month. Leave until the skin resists a thumbnail, then cure in the sun 1–2 weeks before storing.
  • Basil — still producing until around April; pick before flowering.
  • Beetroot, carrot, silverbeet, spinach — all within their long harvest windows.
  • Broccoli — heads from an August–November sowing are still cropping; keep cutting side shoots.

Garden Jobs for March

Prepare beds for April garlic

Garlic goes in next month. Use March to clear finished summer crops and work in compost rather than leaving soil prep until planting day.

Watch tomatoes for late blight pressure

Cooler nights and heavier autumn dew increase blight risk. Water at the base rather than overhead, and remove affected foliage promptly.

Clear spent crops as they finish

Pull courgettes, cucumbers and beans as they tail off rather than leaving half-productive plants taking up space autumn sowings could use.

Common March Mistakes

Missing the last lettuce sowing

Once March closes out, the sowing window doesn't reopen until spring. Waiting until the current crop is eaten before sowing again often means missing the window entirely.

Sowing brassicas or garlic too early

Broccoli, kale and garlic all have sowing windows that start later — August for the brassicas, April for garlic. Getting ahead of the data costs more than it saves.

Leaving pumpkins on the vine without curing

Pumpkins need curing in the sun before storage, not immediate harvest and storage — skipping it shortens how long they'll keep.

Looking Ahead

April brings the start of the frost-risk period in the temperate zone and the opening of the garlic sowing window — the two are related, since garlic actually benefits from cooler soil to establish before winter dormancy. Use the last of March's warm soil to get autumn crops in before that shift.

Ready for next month? See *What to Plant in NZ Temperate in April*, or explore the full NZ Temperate Planting Calendar →.