May 1 is the sourced first-frost date for Wellington's inland valley suburbs — Johnsonville, Ngaio, Brooklyn — while the coastal suburbs stay effectively frost-free right through. That split is the real story of a Wellington May: the temperate zone's frost period has technically been open since April, but this is the month it actually shows up here, and only in half the city.

It also happens to be the last-call month for four of this zone's longest-running sowing windows — garlic, beetroot, carrot and silverbeet all close out at the end of May.

The Wellington May Growing Context

Soil is cooling and growth has slowed across the board, same as anywhere in the temperate zone this time of year. What's different here is where and how that cooling actually bites:

  • Coastal Wellington suburbs are protected from frost by the same wind that made March a battle for staking — moving air stops the still, cold conditions frost needs.
  • Inland and valley suburbs lose that protection and see their first frost right around May 1, per Wellington's regional frost data.
  • The Wairarapa, on the other side of the Remutaka Range, sees genuine mid-continental frosts and a shorter effective season than the rest of the region.
  • Four sowing windows — garlic, beetroot, carrot, silverbeet — close at the end of this month regardless of which side of the frost line you're on.

If you're in a coastal suburb, treat May 1 as someone else's deadline. If you're inland, it's real, and it lands squarely inside this month.

What to Sow Now — Last Call for the Regulars

Garlic closes its April–May sowing window at the end of this month — miss it and the window doesn't reopen until next April. Plant cloves 5cm deep, 15cm apart; the roughly seven-month run to harvest lands in November–December regardless of when in this window you plant. Best Garlic Varieties for NZ Temperate Gardeners covers the cultivar picks in more depth than fits here.

Beetroot, carrot and silverbeet all close their windows this month too (Beetroot and Silverbeet run August–May, Carrot September–May). Direct sow all three — none transplant well — and keep the seedbed evenly moist, since cooling soil slows germination more than it did even a month ago. Growing Silverbeet Year-Round in NZ is worth a look if you want silverbeet cropping through the winter ahead rather than just this last sowing.

Pak choy is still inside its August–May window and, unlike the four crops above, isn't up against a hard May deadline — a useful backstop if you've missed the others.

New This Season: Citrus Trees

Lemon, mandarin and orange are all inside their April–September planting window now, going in as potted nursery stock rather than sown seed. This is where Wellington's wind matters again, in a different way than it did for March's seedlings: all three are only frost-tolerant, not frost-hardy, and a young citrus tree in an inland valley is walking straight into that May 1 frost date on top of the wind exposure that varies block to block across this city. A sheltered, sunny spot does double duty here — cutting wind stress and softening the tree's first frost exposure at once. Best Lemon, Best Mandarin and Best Orange Varieties cover which cultivar suits which situation.

What's Already Cropping

Climbing beans, lettuce and peas all close out their harvest windows this month — pick everything usable before they finish. Feijoa (harvest March–July) and Jerusalem artichoke (April–August) are both mid-season, and pumpkin runs through to June — test the skin with a thumbnail and cut once it stops denting, then cure it in the sun before storing. Radish is still going too, on its long October–June window.

Garden Jobs for a Wellington May

Treat the sowing deadline as real, not a suggestion. Garlic, beetroot, carrot and silverbeet are off the table island-wide once May ends, regardless of coastal or valley conditions.

Frost-check new citrus plantings specifically if you're inland. A young tree in Johnsonville or Ngaio is meeting real frost risk for the first time this year right now — a frost cloth on forecast cold nights costs little and protects an investment that takes years to establish.

Clear finished beans, lettuce and pea plants as they close out rather than leaving spent plants tying up bed space a winter mulch or cover crop could use instead.

The Wellington-Specific Mistake

Applying one frost date to the whole city is the easiest mistake to make this month. The zone-level frost window opened back in April, but for a coastal Wellington garden that's largely academic — it's the inland valleys where May 1 is a real, specific date worth planning around, whether that's holding off a citrus planting a fortnight or having frost cloth ready before the first cold night hits.

Ready for the full picture? See the NZ Temperate Planting Calendar → for every crop's sow, transplant and harvest windows.