How to Grow Komatsunas
On this page
Komatsuna (Brassica rapa var. perviridis) — annual or biennial grown as an annual.
The short answer
- Site
- soil pH 5.5–6.8
- Biggest risk
- Downy mildew
Core growing advice on this page is checked against named horticultural sources — see References.
Komatsuna (Brassica rapa var. perviridis)
3 sources cited · Verified
At a Glance
Quick Facts
| Factor | Value |
|---|---|
| Soil pH | 5.5 - 6.8 |
| Soil texture | fertile, loamy (MorningChores) |
| Drainage | well-drained |
| Lifecycle | annual or biennial grown as an annual |
| Edible parts | leaves |
Soil & Growing Conditions
Water: moisture-retentive, well-draining (MorningChores)
Soil pH range
Span reflects genuine variation between the cited authorities, not a single agreed figure.
Growth Stages
| Stage | BBCH | Notes |
|---|---|---|
| Sowing | 0 | Sow 1/4-1/2in deep, 6in apart with 18-24in between rows, spring through late summer; successive sowings every two weeks (MorningChores). |
| Thinning | 3 | Thin to 4in apart for baby leaves, or 8in for mature plants (Seedy Farm). |
| Leaf growth | 4 | Nitrogen-rich fertiliser at planting, liquid feed 15-20 days after germination; full sun with afternoon shade in harsh climates (MorningChores). |
| Harvest | 8 | Matures in 30-40 days; cut leaving at least 2in of stem for regrowth, usually good for at least two cuttings (MorningChores, Seedy Farm). |
Harvest & Storage
When to pick: Matures in 30-40 days; harvest leaves at any stage. Cut with shears or a sharp knife leaving at least 2 inches of stem so the plant regenerates -- usually at least two cuttings are possible. Pluck any flowers to maintain productivity (MorningChores, Seedy Farm).
Diseases
Pests
Komatsuna, Leaf to Table
Plan your Komatsunas planting
Timing for Komatsunas follows soil temperature and frost, not the calendar date. The Global vegetable planting calendar explains the method. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.
Growing Komatsuna in another region
Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.
Sources
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A secondary gardening reference rather than a university or horticultural authority, used as the primary source: no RHS page or university extension publication could be located for komatsuna specifically, so this well-sourced grower guide is used with that gap explicitly noted rather than left unsourced. Optimal temperature range 45-80°F; bolts in heat but can't handle a hard frost either -- some cold-tolerant hybrids tolerate below 10°F. Full sun, with afternoon shade in harsh climates. Soil pH 5.6-7.5, moisture-retentive, fertile, loamy, well-draining; nitrogen-rich fertiliser at planting, liquid feed 15-20 days after germination. Sow 1/4-1/2in deep, spaced 6in apart with 18-24in between rows; sow spring to late summer (year-round for some hybrids), every two weeks for a constant supply. Matures in 30-40 days; harvest leaves at any stage, the plant regenerates for continuous picking; pluck flowers to maintain productivity. PESTS: flea beetles, cabbage loopers, aphids. DISEASES: leaf spot, downy mildew (grey fluff on leaves, treat with organic fungicide and improve spacing for airflow), black leg.
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A secondary gardening reference rather than a university or horticultural authority, used only for sowing succession and harvest-cut detail not covered above, not contradicted by it. Direct sow in shallow furrows 0.5-1cm deep, rows 15-20cm apart in a garden bed or 10-15cm in a planter. Thin to 4in (10cm) apart for baby leaves used like spinach, or 8in (20cm) for mature plants. Harvest with shears or a sharp knife, slicing outer leaves away as needed, leaving at least 2 inches of stem above ground so the plant continues producing; usually at least two cuttings possible before the plant is spent.
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Mirrors FAO Ecocrop. Fetched and parsed directly for the numeric soil pH range.
These 3 sources are specific to this region. The full list of 3 sources behind this guide (MorningChores, Seedy Farm, Useful Temperate Plants) is in the references of our UK guide to komatsuna; they describe the plant itself, which is the same wherever it grows.
Frequently Asked Questions
What soil pH does komatsuna need?
A pH of about 5.5–6.8. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.
What problems affect komatsuna?
Our data links 2 diseases and 3 pests to this crop. See the sections above for each one and how to manage it.
Plan next season before the problems start
This page gives you the thresholds; the planner turns them into your own calendar. It works from what you can observe and measure in your garden rather than from dates written for somebody else’s latitude.
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How this guide is put together
The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against international horticultural research and extension sources. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.
Related Problem Guides
Last verified 2026-09-02
Related guides
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Where To Go From Here
Take this crop from reading into a written plan for your own beds.
Keep going
Plan the next step
Use the printable SoilCommander planner for your region to turn this guide into sowing dates, bed layouts and weekly garden tasks.