When to Plant Komatsuna in Melbourne, Cool Temperate Guide

Sow now in Cool Temperate Soil 18.5°C, best 7–23°C

Soil temperature is modelled from Open-Meteo forecast (Melbourne), not a live sensor.

What this month normally looks like in Cool Temperate

In October the Cool Temperate zone normally runs 19°C by day and 8°C overnight, with about 67 mm of rain over 9 or 10 wet days. The coldest October night on record across the zone was -3.0°C, so a late frost is not out of the question. Averages 1991 to 2026, 28 postcodes, SILO.

Jump to section
  1. Planting calendar
  2. How to grow
  3. Local tips and varieties
  4. Pests and problems
  5. Harvesting
  6. Storing and preserving
  7. Other zones and related crops
  8. Common questions

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This Komatsuna guide is written for the Cool Temperate zone, which takes in Melbourne, Hobart and Geelong. Somewhere else? Your postcode picks the right one.

Not your zone? Cairns Brisbane Sydney Canberra Alice Springs Perth

Also handy: will it frost this week? and what grows in shade.

Planting window
Mar to May, Aug to Nov
Days to harvest
35 days
Sun
Full sun to part shade
Water
Moderate
Spacing
20 cm apart
Soil pH
6.0–7.5

Komatsuna (Japanese mustard spinach) is a fast, mild leafy brassica that is ready in about 35 days and can be picked at any stage (Direct Compost Solutions).

Komatsuna

Photo: Wikimedia Commons

Planting Calendar for Cool Temperate

  • Jan -
  • Feb -
  • Mar D
  • Apr D
  • May D
  • Jun -
  • Jul -
  • Aug D
  • Sep D
  • Oct D
  • Nov D
  • Dec -

S = Seed Tray   T = Transplant   D = Direct Sow

Want a nudge when it is sowing time?

One email a week with what is worth planting in the Cool Temperate zone right now, Komatsuna included, plus which veg has jumped in price at the supermarket. Free, and you can stop it in one click.

How to Grow Komatsuna in Cool Temperate Australia

Soil
Well drained soil with compost, pH 6.0 to 7.5 (Direct Compost Solutions).
Salt
Moderately sensitive. Copes with a little salt, but the harvest drops on salty bore water.
pH Range
6.0-7.5
Sunlight
Full sun to part shade (The Seed Collection, Direct Compost Solutions).
Spacing
20cm apart, 40cm between rows
Watering
Moderate, steady water (Direct Compost Solutions).
Good companions
Lettuce, Carrot, Radish
Grow before it
Legumes (Beans - Dwarf, Peas, Broad Beans)
Grow after it
Fruiting crops (Tomato, Capsicum, Zucchini)

Give the bed 3 turns before brassicas go back in. The cabbage family is hungry for nitrogen and shares club root and other soil diseases.

Members see the exact salt threshold, how much harvest it loses as salt rises, and what to grow instead. See what members get

Cool Temperate Growing Tips for Komatsuna

Recommended Varieties

  • Komatsuna

Key Challenges

  • Cold seedlings in winter

Pro Tips

  • Autumn sowings stand through frost (The Seed Collection)

Pests and problems for Komatsuna in Cool Temperate

Members see each pest score and pest risk alerts for your area. See what members get

Browse the full pest library →

Harvesting Komatsuna

When ready: Any stage from baby leaf; full leaves about 30 cm long (Direct Compost Solutions).

How to harvest: Pick outer leaves and let the plant keep growing, or cut whole (Direct Compost Solutions).

Storing and preserving komatsuna

How to keep it
  • Blanching and freezing. Blanch 2 minutes, cool, drain, pack (NCHFP). Keeps: 8-12 months.

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What members get

  • Soil and weather from your nearest station
  • An email when it's time to sow
  • Your own garden plan, including planning from a photo
  • Price history and price alerts
  • Pest risk alerts for your area
  • Full salt and canning detail

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Common Questions About Komatsuna

When do you plant komatsuna in Australia?

It depends on your climate zone, not the calendar month alone. Planting months by zone:

Can you grow komatsuna all year round in Melbourne?

No. In the Cool Temperate zone the planting months are Mar to May, Aug to Nov. Outside that window it either bolts, sulks or gets cut down by the weather.

When should I plant Komatsuna in Melbourne?

Sow direct March to May and August to November, the spring and autumn seasons The Seed Collection gives. Mature plants are frost hardy and survive winter; young seedlings are cold sensitive, so avoid midwinter sowing (The Seed Collection). Months derived from that advice.

What soil temperature do Komatsuna need?

Komatsuna germinate best when soil temperature is between 7°C and 23°C.

How do I know when Komatsuna are ready to harvest?

Any stage from baby leaf; full leaves about 30 cm long (Direct Compost Solutions).

What are the best Komatsuna varieties for Melbourne?

Recommended varieties for the Cool Temperate zone include: Komatsuna.

What grows well with Komatsuna?

Good companion plants for Komatsuna include: Lettuce, Carrot, Radish.

Are komatsuna salt tolerant?

Only a little. Komatsuna are moderately sensitive to salt, so the harvest drops on salty bore water. Mix salty water with rainwater, and mulch the bed.

Which zone am I in?

Type your postcode into the box near the top of the page and it tells you, and links this crop in your own zone if it differs. Or look it up on the grow zone map. This page is the Cool Temperate zone, Melbourne is its reference city.