Short answer: December is the first month all year with no new sowing or transplant window opening — everything sowable now has been sowable since October or November. What it lacks in new starts it makes up for in harvest: tomato, broccoli, carrot, peas and broad beans all come into harvest for the first time, on top of garlic, kale, coriander and mustard greens already cropping.

The NZ Temperate December Growing Context

The frost period closed at the end of November, so December is the first fully frost-free month on the calendar. That's exactly why nothing new opens this month — the crops that needed frost risk to clear (courgette, pumpkin, beans, the perennial tubers) already started sowing in November, and everything else has been open since spring.

Typical December conditions in temperate gardens:

  • Fully frost-free — the growing season's most settled stretch
  • No new sowing or transplant windows this month
  • Three crops close their sowing windows: Jerusalem artichoke, mizuna, yacon
  • Broccoli's transplant window also closes this month
  • Sixteen crops in active harvest, the widest list of the year

What to Sow This Month

Nothing new opens in December, but plenty is still sowable from earlier windows: basil, climbing beans, beetroot, carrot, courgette, cucumber, lettuce, pak choy, peas, pumpkin, radish, silverbeet and spinach all remain open. Quick crops like radish, lettuce, pak choy and spinach are worth succession sowing into any bed space freed up as earlier crops finish.

Last call: Jerusalem Artichoke, Mizuna and Yacon

  • Jerusalem Artichoke and Yacon — both perennial tuber crops, sown as tubers or crown divisions rather than seed, close their planting windows at the end of December. Get them in now if you haven't already; both are frost-anchored judgment calls rather than precisely sourced dates, since Koanga Institute is the only supplier with any record of either crop.
  • Mizuna — sowing closes at month end, open since August. Egmont lists a second Feb–Mar window if you miss this one.

Transplant This Month

Basil and cucumber, both transplanting since November, continue through to February. Broccoli's transplant window closes this month — if you still have seedlings in trays from an August or September sowing, get them into the ground now rather than waiting into January.

What to Harvest This Month

Five crops come into harvest for the first time this month:

  • Tomato — first fruit from the October transplant, cropping through to autumn frost.
  • Broccoli — heads from the August–November sowing, central head first, then side shoots.
  • Carrot, Peas — both entering harvest for the first time from earlier sowings.
  • Broad Beans — from an autumn sowing, cropping through to February.

Continuing from earlier months: beetroot, coriander, lettuce, mizuna, pak choy, radish, silverbeet and spinach are all comfortably within their harvest windows.

Last call for harvest: garlic and mustard greens both close their harvest windows at the end of December. Lift any remaining garlic promptly — bulbs left in warm December soil are prone to splitting rather than gaining further size.

Garden Jobs for December

Finish lifting garlic before it splits

Garlic's harvest window closes this month. Warm soil doesn't help mature bulbs get bigger — it just increases the risk of splitting or rot the longer they sit.

Get support under the heavy crops

Tomato, cucumber, pumpkin and climbing beans are all bulking up fast now. Check stakes, cages and trellis are still holding rather than waiting for something to collapse under its own weight.

Refill beds as the last-call crops finish

Jerusalem artichoke, mizuna and yacon all close their sowing windows this month, and garlic and mustard greens finish harvest. Use the freed space for a quick succession crop — radish, lettuce or pak choy — rather than leaving it bare over summer.

Common December Mistakes

Assuming "nothing new to sow" means nothing to do

No new windows opening doesn't mean the garden is on autopilot — beds vacated by garlic, mustard greens and the closing sowing windows still need refilling, and everything already growing needs regular watering as the first proper frost-free heat arrives.

Leaving garlic in the ground too long

Once the harvest window closes at month end, mature bulbs left in warm soil split or rot rather than improving. Lift promptly and cure in a dry, airy spot.

Looking Ahead

January brings courgette into harvest for the first time, joining everything already ripening this month, while kale reaches the last month of its own harvest window. Basil, beans, beetroot, carrot, courgette, cucumber, lettuce, pak choy, peas, pumpkin, radish, silverbeet and spinach all keep going regardless, still inside the same sowing windows that opened in October and November.

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