Komatsuna care guide
Brassica rapa var. perviridis
Also known as: Japanese mustard spinach
Pets and children
We haven't been able to confirm how this plant affects pets or small children. If any is eaten, consult a veterinarian or a doctor.
How often to water Komatsuna
- Spring–Summer (Mar–Sep)
- Every 2 days
- Water thoroughly once the topsoil dries, as a guide; keep the seedbed moist until germination, and water in the morning in summer.
- Autumn (Oct–Nov)
- Every 2 days
- The easiest season: water about when the topsoil dries, as a guide, without keeping it soggy.
- Winter (Dec–Feb)
- Every 4 days
- Cold keeps the soil damp longer, so as a guide water in the morning about two to three days after it dries.
Light and placement for Komatsuna
A sunny, airy spot outdoors is about right; it can be sown most of the year, but from spring to autumn insects are generally a problem, so an insect net from sowing on prevents most losses.
Overwintering Komatsuna
Overwintering guide: −5°C (23°F) or above
Cold-hardy, and frost generally sweetens the leaves; it grows outdoors down to about −5°C, though slowly, and a fleece cover shortens the wait to harvest.
Fertilizing and repotting Komatsuna
Fertilizer
In soil with a base fertilizer, one dose of diluted liquid feed at the three-to-four-leaf stage is usually enough; it is harvested within about one to two months and needs little.
When to repot
Spring–Summer (Mar–Sep), Autumn (Oct–Nov)
Common problems with Komatsuna
- Cabbage worms, diamondback moths, and aphids riddle the leaves with holes.
- Thinned too late, the crowded plants end up spindly and small.
- Summer heat makes it bolt and the leaves turn tough.
Tips for growing Komatsuna
- An insect net put on right after sowing cuts pest damage dramatically.
- The thinnings are good to eat as baby greens.
- Harvest whole plants at about 20 to 25 cm tall, or pick the outer leaves as needed.
These are AI-generated general guidelines. They vary with the variety, the placement and the pot size. For effects on pets or children, consult a veterinarian or a doctor.
Keep your plant log going
Greenery is a free app that keeps your plant care going, with watering reminders and photo records. Available on iOS and Android.
