A carrot row that stays bare, or comes up patchy, is almost always a moisture problem, not a seed problem — carrot seed is sown shallow and takes two to three weeks to emerge, and it has no reserves to fall back on if the surface dries out even briefly during that stretch. Soil crusting, sowing too deep, cold soil, and old seed are the other real culprits, roughly in that order.

What's most likely going on

  • A dry spell during germination. Carrot's long germination window is the thing that trips people up — a day or two without water partway through can kill seed that's already partly germinated, with nothing visible above ground to show for it either way.
  • A crusted or compacted soil surface. Heavy or poorly worked soil can cap over after rain or watering, and carrot's thread-fine seedlings often can't physically push through it even when the seed itself has germinated underneath.
  • Sown too deep. Carrot seed only needs about 6mm of cover. Buried deeper than that, the emerging shoot can run out of energy before it reaches daylight.
  • Soil still too cold. Carrot wants soil reliably above roughly 10°C. Sown into ground that hasn't warmed yet, it germinates slowly and unevenly — or rots before it sprouts if the soil's also wet.
  • Old or poorly stored seed. Carrot seed is only rated for about a year of reliable viability in normal home storage, dropping further the second year — a row sown from a two-year-old leftover packet can simply have too few live seeds left in it.

What temperate frost dates change

Our carrot calendar doesn't change by zone — direct sow September to May, harvest December to August, per Egmont's culture guide. What does change is how fast the ground actually warms once you're into that window. A temperate garden's soil clears the roughly 10°C carrot threshold sooner than a colder garden's does, so more of the sowing window is usable at full pace here without cold soil itself being the reason a sowing fails. The moisture and crusting risks above are about weather and soil structure on the day, not climate, so they need exactly the same attention in a temperate garden as anywhere else — don't assume a mild zone is forgiving of a dry week.

What to do about it

  • Keep the surface consistently moist for the whole two-to-three-week window, not just at sowing — water little and often rather than heavily and infrequently.
  • Cover the row after sowing to hold moisture in, and check it daily. Newspaper, cardboard, or shade cloth all work, but remove the cover the instant the first green shoots appear — light-starved seedlings under a cover left too long die just as fast as dry ones do.
  • Prepare the bed before sowing, not after. Dig deep, break up clods, and work in compost ahead of time on heavier soil so the surface doesn't cap over once it's watered.
  • Sow shallow and firm lightly — about 6mm of cover — then water in gently so seed isn't washed out or driven deeper.
  • Sow fresh seed each season rather than carrying over an old packet, and if you're unsure of a packet's age, run a quick damp-paper-towel germination test before committing a whole row to it.

Cultivar notes

The Koanga Institute cultivars sourced for this zone — Akaroa Long Red, Juwarot, Kuroda, Oxheart, Paris Market, Touchon and White Belgium — repeat the same practical instruction across the board: scatter-sow, lightly cover with soil, then cover the bed with an old sheet or 70% shade cloth while germinating, removing it once about 70% of seedlings show their first two leaves. That's a real supplier practice independently confirming the same principle above — protect the seedbed's moisture, but don't leave the cover on past the point the seedlings need light.

Next season

Once a row does come up reliably, the next real concern for carrots in a temperate garden is protecting the seedlings from carrot rust fly — see Carrot Rust Fly in NZ — Protecting Your Carrot Crop for identification and control, including why sowing thinly (so you don't need to thin the row later) matters for keeping flies away in the first place.

More on this zone: see the full NZ Temperate Planting Calendar →.